/* BYTE Academy – "smart casual" theme: warm neutrals, one confident indigo accent,
   soft depth, generous spacing. Light/dark follows Telegram (data-theme on <html>). */

:root {
  --bg: #ffffff;            /* card surface */
  --bg2: #f5f3ef;           /* page background / inset fields */
  --surface-3: #ebe8e1;
  --text: #1c1b22;
  --hint: #75737d;
  --link: #4f46e5;
  --btn: #4f46e5;
  --btn-2: #7c3aed;
  --btn-text: #ffffff;
  --accent-soft: color-mix(in srgb, var(--btn) 10%, transparent);
  --line: rgba(28, 27, 34, .07);
  --ok: #16a34a;
  --bad: #dc2626;
  --warn: #d97706;
  --code-bg: #17161d;
  --code-text: #e8e6f0;
  --shadow: 0 1px 2px rgba(28, 27, 34, .04), 0 6px 20px -6px rgba(28, 27, 34, .10);
  --shadow-lg: 0 14px 34px -12px rgba(79, 70, 229, .45);
  --radius: 18px;
  --radius-sm: 12px;
  --font: "Plus Jakarta Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Consolas, monospace;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #1a1a22; --bg2: #111117; --surface-3: #262631;
    --text: #ecebf3; --hint: #9b99a8; --link: #a5b4fc;
    --btn: #6366f1; --btn-2: #8b5cf6;
    --line: rgba(255, 255, 255, .07);
    --ok: #4ade80; --bad: #f87171; --warn: #fbbf24;
    --code-bg: #0c0c11;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px -10px rgba(0, 0, 0, .6);
    --shadow-lg: 0 14px 34px -12px rgba(99, 102, 241, .55);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #1a1a22; --bg2: #111117; --surface-3: #262631;
  --text: #ecebf3; --hint: #9b99a8; --link: #a5b4fc;
  --btn: #6366f1; --btn-2: #8b5cf6;
  --line: rgba(255, 255, 255, .07);
  --ok: #4ade80; --bad: #f87171; --warn: #fbbf24;
  --code-bg: #0c0c11;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px -10px rgba(0, 0, 0, .6);
  --shadow-lg: 0 14px 34px -12px rgba(99, 102, 241, .55);
  color-scheme: dark;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--bg2);
  color: var(--text);
  font: 15px/1.5 var(--font);
  letter-spacing: -.005em;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
}

main { padding: 20px 16px 104px; max-width: 720px; margin: 0 auto; animation: fade-in .25s ease; }
@keyframes fade-in { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

h1 { font-size: 26px; line-height: 1.2; font-weight: 800; letter-spacing: -.02em; margin: 4px 0 14px; }
h2 {
  font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: .08em;
  color: var(--hint); margin: 26px 4px 10px;
}
h3 { font-size: 16px; font-weight: 700; letter-spacing: -.01em; margin: 0 0 4px; }
p { margin: 6px 0; }
b { font-weight: 700; }
.muted { color: var(--hint); font-size: 13px; }

/* ---------- surfaces ---------- */
.card {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 12px;
  box-shadow: var(--shadow);
}
.card.clickable { cursor: pointer; transition: transform .15s ease, box-shadow .15s ease; }
.card.clickable:active { transform: scale(.985); }
@media (hover: hover) { .card.clickable:hover { transform: translateY(-1px); } }

/* Home hero */
.hero {
  position: relative; overflow: hidden;
  border-radius: 22px; padding: 20px 18px 18px; margin-bottom: 14px;
  color: #fff;
  background:
    radial-gradient(120% 90% at 100% 0%, rgba(255, 255, 255, .22), transparent 55%),
    linear-gradient(135deg, var(--btn), var(--btn-2));
  box-shadow: var(--shadow-lg);
}
.hero::after {
  content: ""; position: absolute; right: -40px; bottom: -60px;
  width: 180px; height: 180px; border-radius: 50%;
  background: rgba(255, 255, 255, .08);
}
.hero .eyebrow { font-size: 12px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; opacity: .8; }
.hero h1 { margin: 4px 0 14px; color: #fff; }
.hero .level-row { display: flex; justify-content: space-between; font-size: 13px; opacity: .9; }
.hero .bar { background: rgba(255, 255, 255, .22); }
.hero .bar > div { background: #fff; }

.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.stat {
  background: var(--bg); border: 1px solid var(--line); box-shadow: var(--shadow);
  border-radius: var(--radius-sm); padding: 14px 6px 12px; text-align: center;
}
.stat b { display: block; font-size: 20px; font-weight: 800; letter-spacing: -.02em; font-variant-numeric: tabular-nums; }
.stat span { color: var(--hint); font-size: 12px; font-weight: 500; }
.stat small { font-size: 13px; color: var(--hint); font-weight: 500; }
.stats + .stats { margin-top: 10px; }

.bar { height: 8px; background: var(--surface-3); border-radius: 99px; overflow: hidden; margin-top: 10px; }
.bar > div {
  height: 100%; border-radius: 99px;
  background: linear-gradient(90deg, var(--btn), var(--btn-2));
  transition: width .6s cubic-bezier(.2, .8, .2, 1);
}

.row { display: flex; align-items: center; gap: 12px; }
.row .grow { flex: 1; min-width: 0; }

.badge {
  font-size: 12px; font-weight: 600; padding: 4px 10px; border-radius: 99px;
  background: var(--accent-soft); color: var(--link); white-space: nowrap;
}
.badge.ok { background: color-mix(in srgb, var(--ok) 14%, transparent); color: var(--ok); }
.badge.warn { background: color-mix(in srgb, var(--warn) 16%, transparent); color: var(--warn); }
.badge.bad { background: color-mix(in srgb, var(--bad) 14%, transparent); color: var(--bad); }

/* ---------- lessons ---------- */
.lesson-item {
  display: flex; align-items: center; gap: 12px; padding: 11px 4px;
  border-top: 1px solid var(--line); cursor: pointer; border-radius: 10px;
  transition: background .15s;
}
.lesson-item:first-of-type { border-top: 0; }
.lesson-item:active { background: var(--bg2); }
.lesson-item .num {
  width: 30px; height: 30px; border-radius: 10px; flex: none;
  background: var(--surface-3); display: grid; place-items: center;
  font-size: 13px; font-weight: 700; color: var(--hint);
}
.lesson-item.done .num { background: color-mix(in srgb, var(--ok) 16%, transparent); color: var(--ok); }
.lesson-body { line-height: 1.65; }
.lesson-body ul { padding-left: 20px; margin: 6px 0; }

/* ---------- buttons ---------- */
button, .btn {
  font: inherit; font-weight: 600;
  border: 0; border-radius: var(--radius-sm);
  padding: 12px 16px;
  background: linear-gradient(135deg, var(--btn), var(--btn-2));
  color: var(--btn-text);
  cursor: pointer;
  box-shadow: 0 6px 16px -8px color-mix(in srgb, var(--btn) 70%, transparent);
  transition: transform .12s ease, opacity .15s ease, filter .15s ease;
}
button:active { transform: scale(.97); }
@media (hover: hover) { button:hover { filter: brightness(1.06); } }
button:disabled { opacity: .5; transform: none; }
button.secondary { background: var(--surface-3); color: var(--text); box-shadow: none; }
button.small { padding: 7px 12px; font-size: 13px; border-radius: 10px; }
button.danger { background: color-mix(in srgb, var(--bad) 14%, transparent); color: var(--bad); box-shadow: none; }
.btn-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.back { background: none; box-shadow: none; color: var(--link); padding: 0; margin-bottom: 10px; font-weight: 600; }

/* ---------- code ---------- */
code {
  font-family: var(--mono); font-size: 13px;
  background: var(--accent-soft); color: var(--link);
  padding: 1px 6px; border-radius: 6px;
}
pre {
  background: var(--code-bg); color: var(--code-text);
  padding: 14px; border-radius: var(--radius-sm);
  overflow-x: auto; margin: 10px 0; white-space: pre;
  font: 13px/1.6 var(--mono);
  border: 1px solid rgba(255, 255, 255, .06);
}
pre code { background: none; padding: 0; color: inherit; }

textarea.editor {
  width: 100%; min-height: 240px; resize: vertical;
  background: var(--code-bg); color: var(--code-text);
  border: 1px solid rgba(255, 255, 255, .06); border-radius: var(--radius-sm);
  padding: 14px; outline: none; tab-size: 4; white-space: pre;
  font: 13px/1.6 var(--mono);
  box-shadow: var(--shadow);
}
textarea.editor:focus { border-color: color-mix(in srgb, var(--btn) 60%, transparent); }
.output { min-height: 48px; max-height: 260px; overflow: auto; white-space: pre-wrap; word-break: break-word; }
.output.error { color: #ff8a8a; }

/* ---------- forms ---------- */
select, input[type=text], input[type=email], input[type=password], textarea.input {
  font: inherit; color: var(--text);
  background: var(--bg2);
  border: 1.5px solid transparent; border-radius: var(--radius-sm);
  padding: 11px 12px; outline: none;
  transition: border-color .15s, background .15s;
}
select:focus, input:focus, textarea.input:focus {
  border-color: var(--btn); background: var(--bg);
  box-shadow: 0 0 0 4px var(--accent-soft);
}
textarea.input { width: 100%; resize: none; }
::placeholder { color: var(--hint); opacity: .8; }

.field { display: block; margin-bottom: 14px; }
.field span { display: block; font-size: 13px; font-weight: 600; color: var(--hint); margin: 0 2px 6px; }
.field input, .field select { width: 100%; font-size: 16px; }
.form-error {
  color: var(--bad); font-size: 14px; margin: 0 0 10px;
  background: color-mix(in srgb, var(--bad) 10%, transparent);
  padding: 8px 12px; border-radius: 10px;
}

/* ---------- quiz ---------- */
.option {
  display: block; width: 100%; text-align: left; margin-top: 8px;
  background: var(--bg2); color: var(--text); font-weight: 500;
  border: 1.5px solid transparent; box-shadow: none;
}
.option.selected { border-color: var(--btn); background: var(--accent-soft); }
.option.correct { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 14%, transparent); }
.option.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 14%, transparent); }

/* ---------- AI tutor ---------- */
.ai-box { background: var(--accent-soft); border-radius: var(--radius-sm); padding: 12px 14px; margin-top: 12px; }
.ai-box pre { font-size: 12px; }

.chat { display: flex; flex-direction: column; gap: 10px; margin-bottom: 84px; }
.msg {
  max-width: 86%; padding: 10px 14px; border-radius: 18px 18px 18px 6px;
  background: var(--bg); border: 1px solid var(--line); box-shadow: var(--shadow);
  word-wrap: break-word;
}
.msg.user {
  align-self: flex-end; border-radius: 18px 18px 6px 18px; border: 0;
  background: linear-gradient(135deg, var(--btn), var(--btn-2)); color: var(--btn-text);
}
.msg.user code { background: rgba(255, 255, 255, .2); color: inherit; }
.msg pre { font-size: 12px; }
.chat-input {
  position: fixed; left: 12px; right: 12px; bottom: calc(84px + env(safe-area-inset-bottom));
  display: flex; gap: 8px; padding: 8px;
  max-width: 696px; margin: 0 auto;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--line); border-radius: 20px; box-shadow: var(--shadow);
}
.chat-input textarea { flex: 1; max-height: 120px; background: transparent; }
.chat-input textarea:focus { box-shadow: none; border-color: transparent; background: transparent; }

/* ---------- floating tab bar ---------- */
#tabs {
  position: fixed; left: 12px; right: 12px;
  bottom: calc(10px + env(safe-area-inset-bottom));
  max-width: 560px; margin: 0 auto;
  display: flex; padding: 6px;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(18px) saturate(1.4); -webkit-backdrop-filter: blur(18px) saturate(1.4);
  border: 1px solid var(--line); border-radius: 22px;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, .25);
  z-index: 5;
}
#tabs button {
  flex: 1; min-width: 0;
  background: none; box-shadow: none; color: var(--hint);
  border-radius: 16px; padding: 7px 0 6px;
  font-size: 11px; font-weight: 600;
  display: flex; flex-direction: column; align-items: center; gap: 3px;
  transition: color .2s, background .2s;
}
#tabs button svg { width: 22px; height: 22px; }
#tabs button.active { color: var(--btn); background: var(--accent-soft); }

#toast {
  position: fixed; left: 50%; top: 16px; transform: translateX(-50%);
  background: color-mix(in srgb, #1c1b22 92%, transparent); color: #fff;
  backdrop-filter: blur(10px);
  padding: 11px 18px; border-radius: 99px; z-index: 10;
  max-width: 90%; text-align: center; font-weight: 600; font-size: 14px;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, .4);
  animation: toast-in .25s ease;
}
@keyframes toast-in { from { opacity: 0; transform: translate(-50%, -8px); } }

.spinner {
  display: inline-block; width: 16px; height: 16px; vertical-align: middle;
  border: 2px solid var(--surface-3); border-top-color: var(--btn); border-radius: 50%;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- leaderboard ---------- */
.lb-row { display: flex; align-items: center; gap: 12px; padding: 11px 0; border-top: 1px solid var(--line); }
.lb-row:first-child { border-top: 0; }
.lb-row .pos {
  width: 30px; height: 30px; border-radius: 10px; flex: none;
  display: grid; place-items: center; font-weight: 700; font-size: 13px;
  background: var(--bg2); font-variant-numeric: tabular-nums;
}
.lb-row.me { color: var(--btn); font-weight: 700; }
.lb-row.me .pos { background: var(--accent-soft); }

/* ---------- sign in / sign up ---------- */
.auth { max-width: 420px; margin: 28px auto 0; }
.auth h1 { margin-bottom: 4px; }
.auth-logo {
  width: 72px; height: 72px; margin: 0 auto 14px;
  display: grid; place-items: center; font-size: 34px;
  border-radius: 24px;
  background: linear-gradient(135deg, var(--btn), var(--btn-2)); color: var(--btn-text);
  box-shadow: var(--shadow-lg);
}
.segmented {
  display: flex; padding: 4px; margin-bottom: 14px;
  background: var(--surface-3); border-radius: 14px;
}
.segmented button { flex: 1; background: none; box-shadow: none; color: var(--hint); padding: 9px; border-radius: 11px; }
.segmented button.active { background: var(--bg); color: var(--text); box-shadow: var(--shadow); }
.auth a { color: var(--link); text-decoration: none; font-weight: 700; }

/* ---------- profile ---------- */
.avatar {
  width: 48px; height: 48px; border-radius: 16px; flex: none;
  display: grid; place-items: center; font-weight: 800; letter-spacing: .02em;
  background: linear-gradient(135deg, var(--btn), var(--btn-2)); color: var(--btn-text);
}
.profile-grid {
  display: grid; grid-template-columns: auto 1fr; gap: 8px 16px;
  margin-top: 14px; padding-top: 14px; border-top: 1px solid var(--line);
}
.profile-grid span:nth-child(even) { overflow-wrap: anywhere; font-weight: 500; }
[hidden] { display: none !important; }

/* ---------- admin panel ---------- */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 10px; }
.filters input { flex: 1 1 100%; }
.filters select { flex: 1 1 calc(50% - 4px); min-width: 0; }
.student-row { display: flex; gap: 12px; padding: 12px 0; border-top: 1px solid var(--line); cursor: pointer; }
.student-row:first-child { border-top: 0; }
.student-row:active { opacity: .7; }
.student-name { font-weight: 700; }
.student-nums { display: flex; flex-direction: column; align-items: flex-end; text-align: right; white-space: nowrap; font-size: 13px; }
.ellipsis { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.meter { padding: 10px 0; }
.meter-value { font-variant-numeric: tabular-nums; color: var(--hint); font-size: 13px; }
.course-label { font-weight: 700; margin: 14px 0 2px; }
.course-label:first-child { margin-top: 0; }
.lesson-result { display: flex; align-items: center; gap: 10px; padding: 9px 0; border-top: 1px solid var(--line); }
.student-row.static { cursor: default; }
.student-row.static:active { opacity: 1; }
.review-buttons { display: flex; flex-direction: column; gap: 6px; justify-content: center; }
.rank {
  flex: none; align-self: center; min-width: 36px; text-align: center;
  font-weight: 800; font-variant-numeric: tabular-nums; color: var(--hint);
}
.clickable-meter { cursor: pointer; border-top: 1px solid var(--line); }
.clickable-meter:first-child { border-top: 0; }
.clickable-meter:active { opacity: .7; }
details.card summary { cursor: pointer; }
details summary { list-style-position: inside; }

/* ---------- admin login ---------- */
.admin-logo { background: linear-gradient(135deg, #1f2937, #374151); box-shadow: 0 14px 34px -12px rgba(0, 0, 0, .4); }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

/* ---------- top bar (brand + profile button) ---------- */
#topbar {
  position: sticky; top: 0; z-index: 6;
  display: flex; align-items: center; justify-content: space-between;
  max-width: 720px; margin: 0 auto; padding: 10px 16px;
  background: color-mix(in srgb, var(--bg2) 85%, transparent);
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
}
#topbar + main { padding-top: 6px; }
.brand { display: flex; align-items: center; gap: 8px; color: var(--text); text-decoration: none; font-weight: 800; letter-spacing: -.01em; }
.brand-mark {
  width: 28px; height: 28px; border-radius: 9px; display: grid; place-items: center;
  font-size: 15px; color: #fff; background: linear-gradient(135deg, var(--btn), var(--btn-2));
}
.avatar-btn {
  width: 38px; height: 38px; padding: 0; border-radius: 50%;
  font-size: 13px; font-weight: 800; letter-spacing: .02em;
  box-shadow: 0 0 0 2px var(--bg2), 0 0 0 4px transparent;
  transition: box-shadow .2s;
}
.avatar-btn.active { box-shadow: 0 0 0 2px var(--bg2), 0 0 0 4px var(--btn); }

/* ---------- tab badge ---------- */
#tabs button { position: relative; }
#tabs .dot {
  position: absolute; top: 5px; left: calc(50% + 8px);
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--bad); box-shadow: 0 0 0 2px var(--bg);
}

/* ---------- home tiles ---------- */
.tiles { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.tile {
  display: flex; flex-direction: column; align-items: flex-start; gap: 2px; text-align: left;
  background: var(--bg); color: var(--text); border: 1px solid var(--line);
  box-shadow: var(--shadow); border-radius: var(--radius); padding: 14px;
}
.tile span { font-size: 24px; margin-bottom: 6px; }
.tile small { color: var(--hint); font-weight: 500; font-size: 12px; }

/* ---------- profile ---------- */
.profile-head { text-align: center; }
.profile-head h1 { margin: 10px 0 2px; }
.profile-head .level-row { display: flex; justify-content: space-between; font-size: 13px; color: var(--hint); margin-top: 14px; }
.avatar.big { width: 76px; height: 76px; border-radius: 26px; font-size: 26px; margin: 0 auto; }
.avatar.sm { width: 40px; height: 40px; border-radius: 13px; font-size: 14px; }
.avatar.group { background: var(--accent-soft); }
.profile-grid.flat { margin-top: 0; padding-top: 0; border-top: 0; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { padding: 6px 12px; border-radius: 99px; background: var(--bg2); font-size: 13px; font-weight: 600; }

/* ---------- search & lists ---------- */
.search-box { position: relative; margin-bottom: 12px; }
.search-box svg { position: absolute; left: 14px; top: 50%; width: 18px; height: 18px; transform: translateY(-50%); color: var(--hint); }
.search-box input { width: 100%; padding-left: 42px; font-size: 16px; background: var(--bg); border-color: var(--line); }
.list-card { padding-top: 4px; padding-bottom: 4px; }
.person-row { display: flex; align-items: center; gap: 12px; padding: 11px 0; border-top: 1px solid var(--line); cursor: pointer; }
.person-row:first-child { border-top: 0; }
.person-row .grow { flex: 1; }
.person-row:active { opacity: .7; }
.person-row.static { cursor: default; }
.person-row.static:active { opacity: 1; }
.person-row .badge { font-size: 11px; padding: 2px 8px; }

/* ---------- clubs & quizzes ---------- */
.club-icon {
  width: 44px; height: 44px; border-radius: 14px; flex: none;
  display: grid; place-items: center; font-size: 22px; background: var(--bg2);
}
.club-icon.big { width: 56px; height: 56px; border-radius: 18px; font-size: 28px; }
.quiz-summary { display: flex; align-items: center; gap: 12px; margin: 0 4px 14px; }
.quiz-summary .bar { flex: 1; margin-top: 0; }
#quiz.locked .option { cursor: default; }

/* ---------- sign-up: role choice ---------- */
.role-card {
  display: flex; align-items: center; gap: 14px; width: 100%; text-align: left; margin-bottom: 10px;
  background: var(--bg); color: var(--text); border: 1.5px solid var(--line);
  box-shadow: var(--shadow); border-radius: var(--radius); padding: 16px;
}
.role-card:active { border-color: var(--btn); }
.role-card .grow { flex: 1; min-width: 0; }
.role-card b { display: block; font-size: 16px; }
.role-card small { display: block; color: var(--hint); font-weight: 500; font-size: 13px; line-height: 1.4; margin-top: 2px; }
.role-icon {
  width: 48px; height: 48px; border-radius: 16px; flex: none;
  display: grid; place-items: center; font-size: 26px; background: var(--accent-soft);
}
.role-chip {
  display: block; margin: 0 auto 12px; padding: 6px 14px; font-size: 13px;
  background: var(--accent-soft); color: var(--link); box-shadow: none; border-radius: 99px;
}
.form-section {
  font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: .08em;
  color: var(--hint); margin: 22px 2px 12px; padding-top: 16px; border-top: 1px solid var(--line);
}
.field textarea.input { font-size: 16px; }

/* ---------- mentor panel ---------- */
body[data-role="mentor"] #tabs [data-tab="quizzes"] { display: none; }
.notice { background: color-mix(in srgb, var(--warn) 12%, var(--bg)); border-color: color-mix(in srgb, var(--warn) 30%, transparent); }
.answer-input { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.answer-input input[type=text] { flex: 1; min-width: 0; font-size: 16px; }
.answer-input input[type=radio] { width: 22px; height: 22px; flex: none; accent-color: var(--ok); margin: 0; }
.question-card .answers { list-style: none; padding: 0; margin: 10px 0 12px; display: grid; gap: 6px; }
.question-card .answers li { padding: 7px 12px; border-radius: 10px; background: var(--bg2); font-size: 14px; }
.question-card .answers li.correct { background: color-mix(in srgb, var(--ok) 14%, transparent); color: var(--ok); font-weight: 600; }
.question-card .badge { flex: none; }
.mentor-card { background: var(--accent-soft); border-color: transparent; box-shadow: none; }
.student-name .badge { font-size: 11px; padding: 2px 8px; margin-left: 4px; vertical-align: 1px; }

/* =====================================================================
   REFINED LAYER — calm, premium look: cool neutrals, one indigo accent,
   hairline borders, line icons instead of emoji, restrained motion.
   ===================================================================== */
:root {
  --bg: #ffffff; --bg2: #f4f5f8; --surface-3: #e9ebf1;
  --text: #0f1222; --hint: #6b7084; --link: #4338ca;
  --btn: #4f46e5; --btn-2: #4f46e5; --btn-text: #fff;
  --accent-soft: rgba(79, 70, 229, .08);
  --line: rgba(15, 18, 34, .08);
  --ink: #0e1020;                     /* hero / dark panels */
  --shadow: 0 1px 2px rgba(15, 18, 34, .04), 0 4px 16px -8px rgba(15, 18, 34, .10);
  --shadow-lg: 0 20px 40px -24px rgba(15, 18, 34, .55);
  --focus: 0 0 0 3px rgba(79, 70, 229, .18);
  --radius: 16px; --radius-sm: 12px;
}
:root[data-theme="dark"] {
  --bg: #141724; --bg2: #0b0d16; --surface-3: #1f2333;
  --text: #eceef6; --hint: #8d92a8; --link: #a5b4fc;
  --btn: #6366f1; --btn-2: #6366f1;
  --accent-soft: rgba(129, 140, 248, .12);
  --line: rgba(255, 255, 255, .07);
  --ink: #161a2c;
  --shadow: 0 1px 2px rgba(0, 0, 0, .35), 0 6px 20px -10px rgba(0, 0, 0, .6);
  --focus: 0 0 0 3px rgba(129, 140, 248, .25);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #141724; --bg2: #0b0d16; --surface-3: #1f2333;
    --text: #eceef6; --hint: #8d92a8; --link: #a5b4fc;
    --btn: #6366f1; --btn-2: #6366f1;
    --accent-soft: rgba(129, 140, 248, .12);
    --line: rgba(255, 255, 255, .07);
    --ink: #161a2c;
    --shadow: 0 1px 2px rgba(0, 0, 0, .35), 0 6px 20px -10px rgba(0, 0, 0, .6);
    --focus: 0 0 0 3px rgba(129, 140, 248, .25);
  }
}

/* soft accent wash at the top of the page, static */
body::before {
  content: ""; position: fixed; inset: 0 0 auto; height: 320px; z-index: -1; pointer-events: none;
  background: radial-gradient(70% 100% at 50% 0%, var(--accent-soft), transparent 70%);
}

/* ---------- typography ---------- */
h1 { font-size: 26px; font-weight: 800; letter-spacing: -.025em; }
h2 {
  display: flex; align-items: baseline; justify-content: space-between;
  font-size: 15px; font-weight: 700; letter-spacing: -.01em; text-transform: none;
  color: var(--text); margin: 26px 2px 10px;
}
.h2-note { font-size: 12px; font-weight: 600; color: var(--hint); }
.form-section { text-transform: none; letter-spacing: -.01em; font-size: 15px; color: var(--text); }
.field span { font-size: 13px; }

/* gentle entrance for each new screen */
main > * { animation: rise .3s ease-out backwards; }
main > :nth-child(2) { animation-delay: .03s; }
main > :nth-child(3) { animation-delay: .06s; }
main > :nth-child(n+4) { animation-delay: .09s; }
@keyframes rise { from { opacity: 0; transform: translateY(6px); } }

/* ---------- icons ---------- */
.ic { width: 20px; height: 20px; flex: none; display: block; }

/* ---------- top bar ---------- */
#topbar { border-bottom: 1px solid transparent; }
.brand { gap: 10px; }
.brand-mark {
  width: 30px; height: 30px; border-radius: 9px; font-size: 15px; font-weight: 800;
  background: var(--ink); color: #fff; box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .08);
}
.brand-mark i { display: none; }
.brand-word { font-weight: 800; letter-spacing: -.02em; font-size: 16px; }
.brand-word em { font-style: normal; font-weight: 500; color: var(--hint); }
.avatar-btn { background: var(--ink); }

/* ---------- buttons: solid, quiet ---------- */
button, .btn { background: var(--btn); box-shadow: 0 1px 2px rgba(15, 18, 34, .12); }
@media (hover: hover) { button:hover { filter: brightness(1.08); } }
button.secondary { background: var(--bg); color: var(--text); border: 1px solid var(--line); box-shadow: var(--shadow); }
select:focus, input:focus, textarea.input:focus { box-shadow: var(--focus); }

/* ---------- hero ---------- */
.hero {
  background: var(--ink); color: #fff;
  border-radius: 22px; padding: 20px;
  border: 1px solid rgba(255, 255, 255, .06);
  box-shadow: var(--shadow-lg);
}
.hero::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background:
    radial-gradient(60% 80% at 100% 0%, rgba(99, 102, 241, .35), transparent 70%),
    linear-gradient(rgba(255, 255, 255, .035) 1px, transparent 1px) 0 0 / 24px 24px,
    linear-gradient(90deg, rgba(255, 255, 255, .035) 1px, transparent 1px) 0 0 / 24px 24px;
}
.hero::after { display: none; }
.hero > * { position: relative; }
.hero-main { display: flex; align-items: center; gap: 16px; }
.hero-main .grow, .task .grow { flex: 1; min-width: 0; }
@media (max-width: 380px) { .hero h1 { font-size: 21px; } .ring { width: 72px; height: 72px; } }
.hero .eyebrow { font-size: 12px; font-weight: 600; letter-spacing: .02em; text-transform: none; opacity: .6; }
.hero h1 { font-size: 24px; line-height: 1.2; margin: 6px 0 12px; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 6px; }
.pill {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 12px; font-weight: 600; padding: 5px 10px 5px 8px; border-radius: 99px;
  background: rgba(255, 255, 255, .08); border: 1px solid rgba(255, 255, 255, .08);
}
.pill .ic { width: 14px; height: 14px; opacity: .8; }
.hero .level-row { margin-top: 18px; font-size: 12px; opacity: .7; font-variant-numeric: tabular-nums; }
.hero .bar { height: 6px; margin-top: 8px; background: rgba(255, 255, 255, .1); }
.hero .bar > div { background: linear-gradient(90deg, #818cf8, #c7d2fe); }

/* level ring */
.ring { position: relative; width: 84px; height: 84px; flex: none; }
.ring svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.ring circle { fill: none; stroke-width: 6; }
.ring-track { stroke: rgba(255, 255, 255, .1); }
.ring-fill { stroke: #818cf8; stroke-linecap: round; transition: stroke-dashoffset .8s cubic-bezier(.2, .8, .2, 1); }
.ring-inner { position: absolute; inset: 0; display: grid; place-content: center; text-align: center; line-height: 1; }
.ring-inner b { font-size: 26px; font-weight: 800; letter-spacing: -.03em; }
.ring-inner small { font-size: 9px; font-weight: 700; letter-spacing: .12em; opacity: .55; margin-top: 3px; }

/* ---------- stats ---------- */
.stat {
  display: flex; flex-direction: column; align-items: flex-start; gap: 2px;
  text-align: left; padding: 14px; border-radius: var(--radius);
}
.stat .ic { width: 18px; height: 18px; color: var(--btn); margin-bottom: 6px; }
.stat b { font-size: 20px; font-weight: 800; }
.stat b small { font-size: 13px; font-weight: 600; }
.stat span { font-size: 12px; }

/* ---------- cards ---------- */
.card { border-radius: var(--radius); }
.card.clickable { transition: transform .15s ease, box-shadow .2s ease, border-color .2s; }
@media (hover: hover) { .card.clickable:hover { transform: none; border-color: color-mix(in srgb, var(--btn) 30%, var(--line)); } }

/* today checklist */
.task-list { padding: 6px; }
.task { display: flex; align-items: center; gap: 12px; padding: 10px; border-radius: 12px; }
.task + .task { border-top: 1px solid var(--line); border-radius: 0 0 12px 12px; }
.task.clickable { cursor: pointer; transition: background .15s; }
.task.clickable:active { background: var(--bg2); }
@media (hover: hover) { .task.clickable:hover { background: var(--bg2); } }
.task .grow { min-width: 0; }
.task b { display: block; font-size: 15px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.task .muted { font-size: 12.5px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.task-icon {
  width: 38px; height: 38px; border-radius: 11px; flex: none; display: grid; place-items: center;
  background: var(--accent-soft); color: var(--btn);
}
.task.done .task-icon { background: color-mix(in srgb, var(--ok) 12%, transparent); color: var(--ok); }
.task.done b { color: var(--hint); }

/* course progress strip (horizontal scroll) */
.course-strip {
  display: flex; gap: 10px; overflow-x: auto; scroll-snap-type: x mandatory;
  margin: 0 -16px; padding: 2px 16px 6px; scrollbar-width: none;
}
.course-strip::-webkit-scrollbar { display: none; }
.course-card {
  flex: 0 0 168px; scroll-snap-align: start;
  display: flex; flex-direction: column; align-items: flex-start; gap: 2px; text-align: left;
  background: var(--bg); color: var(--text); border: 1px solid var(--line); box-shadow: var(--shadow);
  border-radius: var(--radius); padding: 14px;
}
.course-card b { font-size: 14px; line-height: 1.3; }
.course-card small { color: var(--hint); font-size: 12px; font-weight: 500; }
.course-card .bar { width: 100%; height: 5px; margin-top: 10px; }
.course-mono {
  width: 34px; height: 34px; border-radius: 10px; margin-bottom: 10px;
  display: grid; place-items: center; font-size: 13px; font-weight: 800; letter-spacing: -.02em;
  background: var(--ink); color: #fff; text-transform: capitalize;
}

/* tip of the day */
.tip-card { margin-top: 14px; border-left: 3px solid var(--btn); }
.tip-label { display: flex; align-items: center; gap: 6px; font-size: 12px; font-weight: 700; color: var(--btn); }
.tip-label .ic { width: 15px; height: 15px; }
.tip-card p { margin: 6px 0 0; line-height: 1.55; }

/* explore tiles */
.tile { padding: 14px; transition: border-color .2s; }
.tile span {
  width: 38px; height: 38px; border-radius: 11px; display: grid; place-items: center;
  margin-bottom: 10px; background: var(--accent-soft); color: var(--btn);
}
@media (hover: hover) { .tile:hover { filter: none; border-color: color-mix(in srgb, var(--btn) 30%, var(--line)); } }

/* ---------- bottom tabs ---------- */
#tabs { border-radius: 20px; box-shadow: 0 12px 32px -14px rgba(15, 18, 34, .35); }
#tabs button { border-radius: 14px; }
#tabs button.active { color: var(--btn); background: var(--accent-soft); }

/* ---------- profile ---------- */
.profile-head { background: var(--ink); color: #fff; border-color: rgba(255, 255, 255, .06); box-shadow: var(--shadow-lg); }
.profile-head .muted, .profile-head .level-row { color: rgba(255, 255, 255, .6); }
.profile-head h1 { color: #fff; }
.profile-head .bar { background: rgba(255, 255, 255, .1); height: 6px; }
.profile-head .bar > div { background: linear-gradient(90deg, #818cf8, #c7d2fe); }
.avatar, .avatar-btn { background: var(--ink); color: #fff; }
.avatar.big { background: linear-gradient(135deg, #6366f1, #4338ca); box-shadow: 0 0 0 4px rgba(255, 255, 255, .08); }
.avatar.group { background: var(--accent-soft); color: var(--btn); }

/* ---------- lists ---------- */
.club-icon { background: var(--bg2); box-shadow: inset 0 0 0 1px var(--line); }
@media (hover: hover) { .person-row:not(.static):hover, .lesson-item:hover { background: var(--bg2); } }
.lb-row:nth-child(1) .pos { background: #fef3c7; }
.lb-row:nth-child(2) .pos { background: #e5e7eb; }
.lb-row:nth-child(3) .pos { background: #fde2cf; }
.lb-row.me { background: var(--accent-soft); margin: 0 -10px; padding: 11px 10px; border-radius: 12px; border-top-color: transparent; }

/* ---------- code & AI ---------- */
pre, textarea.editor { border-radius: 12px; }
.option { border: 1px solid var(--line); background: var(--bg); }
.option.selected { border-color: var(--btn); }
.msg.user { background: var(--btn); }
.chat-input:focus-within { box-shadow: var(--shadow), var(--focus); }

/* ---------- auth ---------- */
.auth-logo {
  width: 64px; height: 64px; border-radius: 18px;
  background: var(--ink); box-shadow: var(--shadow-lg), inset 0 0 0 1px rgba(255, 255, 255, .08);
}
.logo-b { font-size: 30px; font-weight: 800; color: #fff; letter-spacing: -.03em; }
.admin-logo { background: #1f2937; }
.role-icon { background: var(--bg2); }

/* ---------- loading: skeleton blocks instead of a lone spinner line ---------- */
main > p.muted:only-child:has(.spinner) {
  font-size: 0; color: transparent; margin: 0;
  height: 380px; border-radius: 22px;
  background:
    linear-gradient(90deg, transparent, color-mix(in srgb, var(--bg) 70%, transparent), transparent) -200px 0 / 200px 100% no-repeat,
    linear-gradient(var(--surface-3), var(--surface-3)) 0 0 / 100% 150px no-repeat,
    linear-gradient(var(--surface-3), var(--surface-3)) 0 166px / 31% 76px no-repeat,
    linear-gradient(var(--surface-3), var(--surface-3)) 50% 166px / 31% 76px no-repeat,
    linear-gradient(var(--surface-3), var(--surface-3)) 100% 166px / 31% 76px no-repeat,
    linear-gradient(var(--surface-3), var(--surface-3)) 0 262px / 100% 118px no-repeat;
  animation: shimmer 1.2s ease-in-out infinite;
}
main > p.muted:only-child:has(.spinner) .spinner { display: none; }
@keyframes shimmer { to { background-position: calc(100% + 200px) 0, 0 0, 0 166px, 50% 166px, 100% 166px, 0 262px; } }


/* ---------- language switch (EN / RU / UZ) ---------- */
.topbar-right { display: flex; align-items: center; gap: 10px; }
.lang-switch {
  display: inline-flex; padding: 3px; gap: 2px; border-radius: 11px;
  background: var(--bg); border: 1px solid var(--line); box-shadow: var(--shadow);
}
.lang-switch button {
  padding: 5px 8px; font-size: 11px; font-weight: 700; letter-spacing: .03em; border-radius: 8px;
  background: none; color: var(--hint); box-shadow: none;
}
.lang-switch button.active { background: var(--ink); color: #fff; }
.auth-lang { display: flex; width: max-content; margin: 0 0 18px auto; }

/* ---------- courses list: collapsible cards ---------- */
details.course { padding: 14px; }
details.course > summary { list-style: none; cursor: pointer; gap: 12px; }
details.course > summary::-webkit-details-marker { display: none; }
details.course .course-mono { margin: 0; flex: none; }
details.course h3 { margin: 0; font-size: 15px; }
details.course .bar { height: 5px; margin-top: 7px; }
details.course[open] > summary { padding-bottom: 8px; border-bottom: 1px solid var(--line); margin-bottom: 4px; }
details.course > summary::after {
  content: ""; width: 8px; height: 8px; flex: none; margin-left: 2px;
  border-right: 2px solid var(--hint); border-bottom: 2px solid var(--hint);
  transform: rotate(45deg) translateY(-2px); transition: transform .2s;
}
details.course[open] > summary::after { transform: rotate(-135deg) translate(-2px, 0); }
.course-mono { font-size: 12px; }

/* ---------- messages button in the top bar ---------- */
.icon-btn {
  position: relative; width: 38px; height: 38px; border-radius: 12px; display: grid; place-items: center;
  color: var(--text); background: var(--bg); border: 1px solid var(--line); box-shadow: var(--shadow);
}
.icon-btn svg { width: 20px; height: 20px; }
#chat-badge {
  position: absolute; top: -5px; right: -5px; min-width: 18px; height: 18px; padding: 0 5px;
  border-radius: 99px; background: var(--bad); color: #fff; font-size: 10.5px; font-weight: 800;
  display: grid; place-items: center; box-shadow: 0 0 0 2px var(--bg2);
}
@media (max-width: 380px) { .brand-word em { display: none; } .topbar-right { gap: 6px; } }

/* ---------- contact actions & direct messages ---------- */
.contact-actions { margin-top: 14px; }
.contact-actions > button { width: 100%; }
.contact-actions .btn-row button { flex: 1; }
.profile-head .contact-actions button.secondary { background: rgba(255, 255, 255, .1); color: #fff; border-color: rgba(255, 255, 255, .15); }
.chat-head {
  position: sticky; top: 58px; z-index: 4; padding: 10px 12px; margin-bottom: 12px;
  background: color-mix(in srgb, var(--bg) 90%, transparent); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); cursor: pointer;
}
.chat.dm .msg { position: relative; padding-bottom: 20px; min-width: 64px; }
.msg-time { position: absolute; right: 12px; bottom: 5px; font-size: 10px; opacity: .55; }
.lesson-item .grow { flex: 1; min-width: 0; }

/* ---------- preferences: background swatches ---------- */
.swatches { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; }
.swatch {
  display: flex; flex-direction: column; align-items: center; gap: 6px; padding: 8px 4px;
  background: none; box-shadow: none; color: var(--text); border-radius: var(--radius-sm);
  font-size: 12px; font-weight: 600;
}
.swatch i {
  width: 38px; height: 38px; border-radius: 50%; background: var(--sw-light);
  border: 1px solid var(--line); box-shadow: inset 0 0 0 1px rgba(0, 0, 0, .06);
}
:root[data-theme="dark"] .swatch i { background: var(--sw-dark); box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .12); }
.swatch.active i { outline: 2px solid var(--btn); outline-offset: 3px; }
.swatch.active span { color: var(--link); }

/* ---------- code practice ---------- */
.practice-progress { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-bottom: 14px; }
.practice-progress .stat small { color: var(--hint); }
.practice-row { cursor: pointer; }
.practice-num {
  min-width: 38px; height: 30px; padding: 0 6px; border-radius: 9px; display: grid; place-items: center;
  background: var(--bg2); font: 600 12px/1 var(--mono); color: var(--hint);
}
.practice-row.solved .practice-num { background: color-mix(in srgb, var(--ok) 15%, transparent); color: var(--ok); }
.level-easy { color: var(--ok); }
.level-medium { color: var(--warn); }
.level-hard { color: var(--bad); }
.badge.level-easy, .badge.level-medium, .badge.level-hard { background: color-mix(in srgb, currentColor 13%, transparent); }
.practice-task { white-space: pre-wrap; }
.practice-task code, .practice-expected { font-family: var(--mono); }
.practice-expected {
  white-space: pre-wrap; background: var(--code-bg); color: var(--code-text); padding: 10px 12px;
  border-radius: var(--radius-sm); font-size: 13px; margin: 6px 0 0;
}

/* ---------- focus mode (full screen for quizzes and problems) ---------- */
.focus-head { margin-bottom: 14px; align-items: flex-start; }
.focus-btn { white-space: nowrap; flex: none; }
body.focus #topbar, body.focus #tabs, body.focus .focus-btn { display: none !important; }
body.focus main { max-width: 960px; padding: 76px 24px 40px; }
#focus-bar {
  position: fixed; z-index: 9; top: calc(12px + env(safe-area-inset-top)); left: 50%; transform: translateX(-50%);
  display: flex; align-items: center; gap: 12px;
  padding: 6px 6px 6px 16px; border-radius: 99px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--line); box-shadow: var(--shadow);
  font-size: 13px; font-weight: 700; white-space: nowrap;
}
#focus-bar[hidden] { display: none; }
#focus-time { font-family: var(--mono); color: var(--hint); font-variant-numeric: tabular-nums; }
@media (max-width: 480px) {
  #focus-bar .focus-label { display: none; }
  body.focus main { padding: 68px 16px 32px; }
}

/* ---------- appearance sheet (🎨 in the top bar) ---------- */
#theme-sheet { position: fixed; inset: 0; z-index: 50; }
.sheet-backdrop { position: absolute; inset: 0; background: rgba(0, 0, 0, .35); animation: fade-in .2s ease; }
.sheet {
  position: absolute; left: 0; right: 0; bottom: 0; max-width: 720px; margin: 0 auto;
  background: var(--bg2); border-radius: 22px 22px 0 0; padding: 16px 16px calc(20px + env(safe-area-inset-bottom));
  box-shadow: 0 -10px 40px rgba(0, 0, 0, .25); animation: sheet-up .25s ease;
}
.sheet .card { margin-bottom: 0; }
@keyframes sheet-up { from { transform: translateY(30px); opacity: 0; } to { transform: none; opacity: 1; } }
@media (max-width: 380px) { .swatches { grid-template-columns: repeat(4, 1fr); gap: 4px; } .swatch i { width: 32px; height: 32px; } }

/* ---------- focus mode on laptops / desktops: split screen ---------- */
.split-only, .focus-keys { display: none; }
@media (min-width: 1000px) {
  body.focus main { max-width: 1440px; padding: 84px 32px 40px; }
  body.focus .split { display: grid; grid-template-columns: minmax(340px, 2fr) 3fr; gap: 24px; align-items: start; }
  body.focus .split-left {
    position: sticky; top: 84px; max-height: calc(100vh - 104px); overflow: auto;
    padding-right: 4px; scrollbar-width: thin;
  }
  body.focus .split-left h1 { margin-top: 0; }
  body.focus .split-right > h2:first-child { margin-top: 0; }
  body.focus .split-right textarea.editor { min-height: 52vh; font-size: 14.5px; }
  body.focus .split-right .output { max-height: 32vh; overflow: auto; }
  body.focus .split-only { display: flex; margin-bottom: 12px; }
  body.focus .practice-nav { display: none; }
  body.focus .focus-keys {
    display: flex; flex-direction: column; gap: 6px; font-size: 13px; color: var(--hint);
  }
  body.focus .focus-keys b { color: var(--text); }
  kbd {
    font: 600 11.5px/1 var(--mono); padding: 3px 6px; border-radius: 6px; color: var(--text);
    background: var(--bg2); border: 1px solid var(--line); box-shadow: 0 1px 0 var(--line);
  }
  /* club quizzes: questions in two columns */
  body.focus #quiz { display: grid; grid-template-columns: 1fr 1fr; column-gap: 28px; }
  body.focus #quiz > :is(#submit-quiz, #quiz-result) { grid-column: 1 / -1; }
  body.focus .split-right #quiz { display: block; }
}
.focus-keys-inline { color: var(--hint); font-weight: 500; }
@media (max-width: 999px) { .focus-keys-inline { display: none; } }

/* =====================================================================
   SIGNATURE LAYER — BYTE's own look: an indigo → violet → cyan gradient,
   a terminal cursor in the logo, glass cards over a slow aurora on the
   sign-in screens. Builds on the layers above; light / dark both work.
   ===================================================================== */
:root {
  --grad: linear-gradient(135deg, #6366f1 0%, #8b5cf6 55%, #22d3ee 100%);
  --grad-btn: linear-gradient(135deg, #5b5bf0 0%, #7c4dff 100%);
  --glow: 0 10px 30px -10px rgba(99, 102, 241, .65);
  --glass: color-mix(in srgb, var(--bg) 78%, transparent);
  --aurora-1: rgba(99, 102, 241, .42);
  --aurora-2: rgba(168, 85, 247, .34);
  --aurora-3: rgba(34, 211, 238, .30);
}
:root[data-theme="dark"] {
  --grad-btn: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
  --glass: color-mix(in srgb, var(--bg) 70%, transparent);
  --aurora-1: rgba(99, 102, 241, .38);
  --aurora-2: rgba(139, 92, 246, .30);
  --aurora-3: rgba(34, 211, 238, .18);
}

.grad-text {
  background: var(--grad); -webkit-background-clip: text; background-clip: text;
  color: transparent; -webkit-text-fill-color: transparent;
}

/* ---------- buttons: gradient with a soft glow and a light sweep ---------- */
button, .btn { background: var(--grad-btn); box-shadow: var(--glow); }
button.secondary { box-shadow: var(--shadow); }
/* quiet buttons: no glow */
.back, .segmented button, .lang-switch button, #tabs button:not(.active), .option, .swatch { box-shadow: none; }

/* big call-to-action buttons: a light sweep now and then */
button.cta {
  position: relative; overflow: hidden; isolation: isolate;
  padding: 15px 18px; font-size: 16px; font-weight: 700; border-radius: 16px; letter-spacing: -.01em;
}
button.cta:not(.secondary):not(:disabled)::after {
  content: ""; position: absolute; inset: 0; z-index: -1; pointer-events: none;
  background: linear-gradient(105deg, transparent 35%, rgba(255, 255, 255, .3) 50%, transparent 65%);
  transform: translateX(-120%); animation: sweep 3.6s ease-in-out 1.2s infinite;
}
@keyframes sweep { 0%, 70% { transform: translateX(-120%); } 100% { transform: translateX(120%); } }

/* ---------- brand ---------- */
.brand-mark { background: var(--grad); box-shadow: var(--glow); }
.avatar-btn { background: var(--grad); box-shadow: var(--glow); }

/* the "B" + blinking cursor */
.logo-caret {
  display: inline-block; width: 3px; height: .9em; margin-left: 3px; border-radius: 2px;
  background: currentColor; vertical-align: -.08em; animation: caret 1.05s steps(1) infinite;
}
@keyframes caret { 50% { opacity: 0; } }

/* ---------- home hero: deeper glow, gradient progress ---------- */
.hero::before {
  background:
    radial-gradient(55% 75% at 100% 0%, rgba(139, 92, 246, .45), transparent 70%),
    radial-gradient(45% 60% at 0% 100%, rgba(34, 211, 238, .22), transparent 70%),
    linear-gradient(rgba(255, 255, 255, .035) 1px, transparent 1px) 0 0 / 24px 24px,
    linear-gradient(90deg, rgba(255, 255, 255, .035) 1px, transparent 1px) 0 0 / 24px 24px;
}
.hero, .profile-head { box-shadow: 0 24px 50px -26px rgba(79, 70, 229, .7); }
.hero .bar > div, .profile-head .bar > div { background: var(--grad); }
.ring-fill { stroke: #a78bfa; filter: drop-shadow(0 0 6px rgba(167, 139, 250, .6)); }
.avatar.big { background: var(--grad); }

/* <html> carries the page colour; a transparent <body> lets the backdrop layers below show through */
body { background: transparent; }

/* page wash: two soft colours instead of one */
body::before {
  height: 380px; opacity: .55;
  background:
    radial-gradient(60% 90% at 15% 0%, var(--aurora-1), transparent 70%),
    radial-gradient(50% 80% at 90% 0%, var(--aurora-3), transparent 70%);
}

/* ---------- tabs: glass bar, gradient active pill ---------- */
#tabs { background: var(--glass); }
#tabs button.active { color: #fff; background: var(--grad-btn); box-shadow: var(--glow); }

/* cards lift a little on hover */
@media (hover: hover) {
  .card.clickable:hover, .tile:hover, .course-card:hover {
    transform: translateY(-2px); box-shadow: var(--shadow), 0 14px 30px -20px rgba(79, 70, 229, .5);
  }
}
.task-icon, .tile span { background: color-mix(in srgb, #8b5cf6 12%, transparent); color: #7c3aed; }
:root[data-theme="dark"] :is(.task-icon, .tile span) { color: #c4b5fd; }

/* =========================== sign-in screens =========================== */
body.auth-mode::before {
  inset: -20%; height: auto; opacity: 1; filter: blur(40px);
  background:
    radial-gradient(32% 26% at 28% 24%, var(--aurora-1), transparent 72%),
    radial-gradient(28% 24% at 76% 30%, var(--aurora-2), transparent 72%),
    radial-gradient(34% 26% at 50% 82%, var(--aurora-3), transparent 72%);
  animation: aurora 18s ease-in-out infinite alternate;
}
body.auth-mode::after {
  content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background:
    linear-gradient(color-mix(in srgb, var(--text) 5%, transparent) 1px, transparent 1px) 0 0 / 28px 28px,
    linear-gradient(90deg, color-mix(in srgb, var(--text) 5%, transparent) 1px, transparent 1px) 0 0 / 28px 28px;
  -webkit-mask-image: radial-gradient(80% 60% at 50% 20%, #000, transparent 75%);
  mask-image: radial-gradient(80% 60% at 50% 20%, #000, transparent 75%);
}
@keyframes aurora {
  0% { transform: translate(0, 0) rotate(0deg) scale(1); }
  50% { transform: translate(3%, -2%) rotate(6deg) scale(1.05); }
  100% { transform: translate(-3%, 2%) rotate(-4deg) scale(1); }
}

.auth { position: relative; max-width: 440px; margin: 8px auto 0; }
.auth .auth-lang { margin-bottom: 8px; }
.auth-back { position: absolute; top: 2px; left: 0; z-index: 1; margin: 0; font-size: 15px; }
.auth-title { text-align: center; font-size: 28px; margin: 0 0 4px; }
.auth-sub { text-align: center; font-size: 14px; margin: 0 0 18px; }
.auth .card {
  background: var(--glass); backdrop-filter: blur(18px) saturate(1.3); -webkit-backdrop-filter: blur(18px) saturate(1.3);
  border: 1px solid color-mix(in srgb, var(--text) 8%, transparent); border-radius: 22px; padding: 18px;
  box-shadow: 0 20px 50px -30px rgba(15, 18, 34, .45);
}
.auth .field input, .auth .field select, .auth textarea.input { padding: 13px 14px; border-radius: 14px; }
.auth-logo {
  position: relative; isolation: isolate; width: 68px; height: 68px; border-radius: 22px; margin: 0 auto 16px;
  display: flex; align-items: center; justify-content: center;
  background: var(--grad); color: #fff; font-size: 30px;
  box-shadow: var(--glow), inset 0 1px 0 rgba(255, 255, 255, .25);
}
.auth-logo::before {
  content: ""; position: absolute; inset: -6px; border-radius: 26px; z-index: -1;
  background: var(--grad); filter: blur(16px); opacity: .45;
}
.auth-logo .logo-b { font-size: 32px; line-height: 1; }
.auth-logo .logo-caret { height: 26px; vertical-align: 0; }
.auth-logo.big { width: 88px; height: 88px; border-radius: 28px; }
.auth-logo.big .logo-b { font-size: 42px; }
.auth-logo.big .logo-caret { height: 34px; width: 4px; }
.auth-logo .ic { width: 32px; height: 32px; }
.auth-logo.admin-logo { background: linear-gradient(135deg, #1f2937, #111827); }
.auth-logo.admin-logo::before { background: #6366f1; opacity: .3; }
.auth-logo.blocked-logo { background: linear-gradient(135deg, #ef4444, #b91c1c); }
.auth-logo.blocked-logo::before { background: #ef4444; }

/* sign-up progress */
.steps { display: flex; align-items: center; justify-content: center; gap: 6px; margin: 4px 0 18px; min-height: 26px; }
.steps i { width: 22px; height: 6px; border-radius: 99px; background: color-mix(in srgb, var(--text) 12%, transparent); transition: all .3s; }
.steps i.done { background: color-mix(in srgb, #8b5cf6 55%, transparent); }
.steps i.active { width: 38px; background: var(--grad); box-shadow: 0 0 12px rgba(139, 92, 246, .6); }
.steps span { margin-left: 8px; font-size: 12px; font-weight: 700; color: var(--hint); }

/* role choice */
.role-card {
  background: var(--glass); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border-radius: 20px; transition: transform .15s, border-color .2s, box-shadow .2s;
}
.role-card .role-icon { background: var(--grad); box-shadow: var(--glow); }
@media (hover: hover) { .role-card:hover { transform: translateY(-2px); border-color: color-mix(in srgb, #8b5cf6 45%, transparent); } }
.role-card:active { transform: scale(.98); border-color: #8b5cf6; }
.role-chip { background: color-mix(in srgb, #8b5cf6 14%, transparent); box-shadow: none; }

/* ---------- welcome ---------- */
.welcome { display: flex; flex-direction: column; min-height: calc(100vh - 140px); }
.welcome-hero { text-align: center; padding-top: 6px; }
.welcome-eyebrow {
  display: inline-block; margin: 0 0 10px; padding: 5px 12px; border-radius: 99px;
  font-size: 12px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase;
  color: var(--link); background: color-mix(in srgb, #8b5cf6 12%, transparent);
  border: 1px solid color-mix(in srgb, #8b5cf6 22%, transparent);
}
.welcome-title { font-size: 34px; line-height: 1.12; letter-spacing: -.035em; margin: 0 0 22px; }
@media (max-width: 380px) { .welcome-title { font-size: 28px; } }

.terminal {
  max-width: 330px; margin: 0 auto 22px; text-align: left; border-radius: 16px; overflow: hidden;
  background: #0d1020; color: #e6e8f5; border: 1px solid rgba(255, 255, 255, .08);
  box-shadow: 0 24px 50px -24px rgba(79, 70, 229, .65);
  animation: float 6s ease-in-out infinite;
}
.terminal-bar { display: flex; align-items: center; gap: 6px; padding: 9px 12px; background: rgba(255, 255, 255, .04); }
.terminal-bar i { width: 9px; height: 9px; border-radius: 50%; background: #ff5f57; }
.terminal-bar i:nth-child(2) { background: #febc2e; }
.terminal-bar i:nth-child(3) { background: #28c840; }
.terminal-bar span { margin-left: auto; font: 500 11px var(--mono); opacity: .5; }
.terminal pre { margin: 0; padding: 12px 14px 4px; background: none; border: 0; font-size: 13.5px; }
.terminal-out { padding: 4px 14px 14px; font: 13.5px var(--mono); color: #86efac; }
.tk-fn { color: #c4b5fd; }
.tk-str { color: #67e8f9; }
@keyframes float { 50% { transform: translateY(-6px); } }

.feature-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 20px; }
.feature {
  display: flex; flex-direction: column; gap: 2px; padding: 14px; border-radius: 18px;
  background: var(--glass); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border: 1px solid color-mix(in srgb, var(--text) 7%, transparent);
}
.feature .ic {
  width: 34px; height: 34px; padding: 7px; margin-bottom: 8px; border-radius: 11px;
  color: #fff; background: var(--grad); box-shadow: var(--glow);
}
.feature b { font-size: 14.5px; }
.feature small { color: var(--hint); font-size: 12.5px; line-height: 1.35; }
.welcome-actions { display: grid; gap: 10px; margin-top: auto; }
.welcome-actions .muted { margin: 2px 0 0 !important; }

/* code-entry field */
#verify-code { font-family: var(--mono); font-weight: 700; }

/* staggered entrance for the welcome blocks */
.welcome > * { animation: rise .5s cubic-bezier(.2, .8, .2, 1) backwards; }
.welcome > :nth-child(2) { animation-delay: .08s; }
.welcome > :nth-child(3) { animation-delay: .16s; }
.welcome > :nth-child(4) { animation-delay: .24s; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

/* ---------- home: practice card ---------- */
.practice-levels { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.practice-level .row { justify-content: space-between; gap: 6px; }
.practice-level b { font-size: 13.5px; }
.practice-level small { font-size: 12px; font-variant-numeric: tabular-nums; }
.practice-level .bar { height: 6px; margin-top: 6px; }
.practice-home .level-bar-easy > div { background: linear-gradient(90deg, #22c55e, #86efac); }
.practice-home .level-bar-medium > div { background: linear-gradient(90deg, #f59e0b, #fcd34d); }
.practice-home .level-bar-hard > div { background: linear-gradient(90deg, #ef4444, #fca5a5); }
.practice-up-next {
  margin: 16px 0 2px; font-size: 12px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--hint);
}
.practice-home .practice-num { background: color-mix(in srgb, #8b5cf6 12%, transparent); color: var(--link); }
@media (hover: hover) { .practice-home .practice-row:hover { background: var(--bg2); margin: 0 -10px; padding: 11px 10px; border-radius: 12px; } }

/* ---------- focus mode: shortcut hint on the button, playground ---------- */
.btn-kbd {
  margin-left: 6px; padding: 1px 6px; border-radius: 5px; font: 700 11px/1.4 var(--mono);
  color: var(--hint); background: var(--bg2); border: 1px solid var(--line);
}
.focus-head { flex-wrap: wrap; }
.focus-head select { max-width: 46%; }
/* writing code full screen: the editor takes the room */
body.focus .playground textarea.editor { min-height: 62vh; font-size: 14.5px; }
body.focus .playground .output { max-height: 24vh; }
@media (min-width: 1000px) {
  body.focus main:has(.playground) { max-width: 1200px; }
  body.focus .playground textarea.editor { min-height: 66vh; }
}

.app-version { text-align: center; font-size: 11.5px; opacity: .7; margin-top: 12px; }

.field-hint { display: block; margin: 6px 2px 0; color: var(--hint); font-size: 12px; font-weight: 500; }

/* Practice problem: output format, worked example and the AI tutor menu */
.practice-format { margin: 8px 0 0; font-size: 14px; color: var(--hint); }
.practice-example { margin-top: 12px; border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 10px 12px; }
.practice-example-title { font-weight: 600; font-size: 14px; margin-bottom: 6px; }
.practice-example-title .muted { font-weight: 400; font-size: 12px; }
.practice-io { display: grid; grid-template-columns: 56px 1fr; gap: 8px; align-items: start; margin-top: 4px; }
.practice-io > span { font-size: 12px; color: var(--hint); padding-top: 7px; }
.practice-io pre { margin: 0; font-family: var(--mono); font-size: 13px; white-space: pre-wrap; word-break: break-word;
  background: var(--accent-soft); border-radius: 8px; padding: 6px 10px; }
.practice-tutor .btn-row { margin-top: 8px; }

/* =====================================================================
   STUDIO LAYER — grown-up and relaxed: Space Grotesk headlines, Inter text,
   JetBrains Mono code, calmer buttons, and a coding workspace for practice.
   ===================================================================== */
:root {
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --display: "Space Grotesk", "Inter", -apple-system, sans-serif;
  --ide-bg: #0f1117; --ide-bar: #161922; --ide-line: rgba(255, 255, 255, .07); --ide-text: #e6e8ef; --ide-dim: #8b90a3;
  --ex-bg: #f6f7fb;
}
:root[data-theme="dark"] { --ex-bg: rgba(255, 255, 255, .04); }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --ex-bg: rgba(255, 255, 255, .04); } }

html, body { font-family: var(--font); font-feature-settings: "cv11", "ss03"; letter-spacing: -.011em; }

/* ---------- lettering ---------- */
h1, h2, h3, .brand-word, .stat b, .hero h1, .welcome-title, .auth-title, .tile b, .pp-title {
  font-family: var(--display);
}
h1 { font-size: 28px; font-weight: 700; letter-spacing: -.035em; line-height: 1.12; }
h2 { font-size: 17px; font-weight: 600; letter-spacing: -.02em; }
h3 { font-weight: 600; letter-spacing: -.02em; }
.brand-word { font-weight: 700; letter-spacing: -.03em; }
.stat b { font-weight: 600; letter-spacing: -.03em; }
.hero h1 { font-weight: 600; letter-spacing: -.035em; }

/* ---------- calmer buttons: no glow, no sweep ---------- */
button, .btn { border-radius: 11px; box-shadow: 0 1px 2px rgba(15, 18, 34, .18); font-weight: 600; letter-spacing: -.01em; }
button.secondary { box-shadow: none; }
button.cta:not(.secondary):not(:disabled)::after { animation: none; opacity: 0; }
#tabs button.active { box-shadow: none; }
button .ic { width: 17px; height: 17px; }
button:has(> .ic) { display: inline-flex; align-items: center; justify-content: center; gap: 7px; }

/* ---------- top bar fits a 390px phone ---------- */
@media (max-width: 430px) {
  .brand-word em { display: none; }
  .topbar-right { gap: 6px; }
}

/* ---------- stats: tidy numbers ---------- */
.stat b { font-size: 21px; font-variant-numeric: tabular-nums; white-space: nowrap; }

/* ---------- practice: header ---------- */
.pp-top { display: flex; align-items: center; gap: 8px; margin: 2px 0 10px; font: 500 13px/1 var(--mono); color: var(--hint); }
.pp-crumb { color: var(--hint); text-decoration: none; }
.pp-top .focus-btn { font-family: var(--font); letter-spacing: -.01em; }
.pp-crumb:hover { color: var(--text); }
.pp-sep { opacity: .5; }
.pp-num { color: var(--text); }
.pp-title { margin: 0 0 10px; font-size: 30px; }
.pp-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin-bottom: 14px; }
.pp-level, .pp-tag {
  display: inline-flex; align-items: center; gap: 6px; height: 26px; padding: 0 10px;
  border-radius: 8px; font-size: 12.5px; font-weight: 600; border: 1px solid var(--line); background: var(--bg);
}
.pp-level i { width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
.pp-tag { color: var(--hint); }
.pp-tag.ok { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 35%, transparent); }

/* ---------- practice: task panel ---------- */
.pp-panel { padding: 18px; }
.pp-label {
  display: flex; align-items: baseline; gap: 8px; margin: 0 0 8px;
  font: 600 11px/1 var(--display); letter-spacing: .12em; text-transform: uppercase; color: var(--hint);
}
.pp-label small { font: 500 12px/1 var(--font); letter-spacing: 0; text-transform: none; opacity: .85; }
.pp-label-ex { margin-top: 18px; }
.pp-panel .practice-task { margin: 0; font-size: 15.5px; line-height: 1.6; }
.pp-format {
  display: flex; align-items: center; gap: 8px; margin-top: 12px; padding: 9px 12px;
  border-radius: 10px; background: var(--accent-soft); color: var(--link); font-size: 13.5px; font-weight: 600;
}
.pp-format .ic { width: 17px; height: 17px; }
.pp-example { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
@media (max-width: 420px) { .pp-example { grid-template-columns: 1fr; } }
.pp-io { border: 1px solid var(--line); border-radius: 12px; background: var(--ex-bg); overflow: hidden; }
.pp-io-label {
  padding: 7px 12px; border-bottom: 1px solid var(--line);
  font: 600 11px/1 var(--display); letter-spacing: .1em; text-transform: uppercase; color: var(--hint);
}
.pp-io pre {
  margin: 0; padding: 10px 12px; background: none; border: 0; border-radius: 0;
  color: var(--text); font: 500 13.5px/1.55 var(--mono); white-space: pre-wrap; word-break: break-word;
}

/* ---------- practice: AI tutor ---------- */
.pp-tutor {
  margin-bottom: 12px; padding: 14px; border-radius: var(--radius);
  border: 1px solid color-mix(in srgb, var(--btn) 22%, var(--line));
  background:
    radial-gradient(120% 140% at 0% 0%, color-mix(in srgb, var(--btn) 9%, transparent), transparent 60%),
    var(--bg);
}
.pp-tutor-head { display: flex; align-items: center; gap: 10px; }
.pp-tutor-mark {
  width: 34px; height: 34px; border-radius: 10px; display: grid; place-items: center; flex: none;
  background: var(--grad, var(--btn)); color: #fff;
}
.pp-tutor-mark .ic { width: 18px; height: 18px; }
.pp-tutor-head b { display: block; font: 600 15px/1.2 var(--display); letter-spacing: -.02em; }
.pp-tutor-head small { color: var(--hint); font-size: 12.5px; }
.pp-tutor-actions { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; margin-top: 12px; }
.pp-tutor-actions button {
  flex-direction: column; gap: 6px; padding: 11px 6px; font-size: 12.5px; line-height: 1.2;
  border-radius: 12px; background: var(--bg); border: 1px solid var(--line);
}
.pp-tutor-actions button .ic { width: 19px; height: 19px; color: var(--link); }
@media (hover: hover) { .pp-tutor-actions button:hover { border-color: color-mix(in srgb, var(--btn) 40%, var(--line)); filter: none; } }
.pp-tutor .ai-box { margin-top: 12px; background: var(--bg2); border: 1px solid var(--line); line-height: 1.6; }
.pp-tutor .ai-box pre { font-size: 12.5px; }
.ai-box.ai-thinking { color: var(--hint); }

/* ---------- practice: the editor workspace ---------- */
.ide {
  border-radius: var(--radius); overflow: hidden; margin-bottom: 12px;
  background: var(--ide-bg); border: 1px solid var(--ide-line); box-shadow: var(--shadow);
}
.ide-bar {
  display: flex; align-items: center; gap: 10px; padding: 8px 8px 8px 12px;
  background: var(--ide-bar); border-bottom: 1px solid var(--ide-line);
}
.ide-tab { display: inline-flex; align-items: center; gap: 7px; flex: 1; min-width: 0; font: 500 13px/1 var(--mono); color: var(--ide-text); }
.ide-tab .ic { width: 16px; height: 16px; color: #a5b4fc; }
.ide-bar select {
  width: auto; max-width: 52%; height: 32px; padding: 0 28px 0 10px; border-radius: 8px; font-size: 13px;
  background-color: rgba(255, 255, 255, .06); color: var(--ide-text); border: 1px solid var(--ide-line);
}
.ide textarea.editor {
  display: block; margin: 0; border: 0; border-radius: 0; box-shadow: none; min-height: 260px;
  background: var(--ide-bg); color: var(--ide-text); font-size: 13.5px; padding: 14px 16px;
}
.ide textarea.editor:focus { box-shadow: inset 0 0 0 1px rgba(165, 180, 252, .35); }
.ide .btn-row { margin: 0; padding: 10px; gap: 8px; background: var(--ide-bar); border-top: 1px solid var(--ide-line); }
.ide .btn-row button { padding: 10px 16px; }
.ide #pr-run { background: rgba(255, 255, 255, .08); color: var(--ide-text); box-shadow: none; }
.ide #pr-submit { background: #22c55e; color: #052e14; flex: 1; box-shadow: none; }
.ide .ide-reset { margin-left: auto; padding: 10px 12px; background: transparent; color: var(--ide-dim); border: 1px solid var(--ide-line); }
.ide .output {
  margin: 0; border: 0; border-top: 1px solid var(--ide-line); border-radius: 0;
  background: #0a0c11; color: var(--ide-text); min-height: 64px; font-size: 13px;
}
.ide .output .muted { color: var(--ide-dim); }
.ide .output.error { color: #fca5a5; }
.ide #pr-ai:empty { display: none; }
.pp-note { margin: 0 2px 12px; }
.pp-solution summary { display: flex; align-items: center; gap: 8px; cursor: pointer; }
.pp-solution summary .ic { width: 18px; height: 18px; color: var(--hint); }

/* ---------- practice: bottom navigation ---------- */
.pp-nav { display: grid; grid-template-columns: 1fr auto 1fr; gap: 8px; margin-top: 4px; }
.pp-nav button { padding: 11px 12px; font-size: 14px; }
.pp-nav #pr-next { justify-self: stretch; }
@media (max-width: 380px) { .pp-nav #pr-list span { display: none; } }

/* ---------- practice list: quieter difficulty labels ---------- */
.practice-row .badge.level-easy, .practice-row .badge.level-medium, .practice-row .badge.level-hard {
  background: none; padding: 0; font-weight: 600; font-size: 12.5px;
}
.practice-row .badge[class*="level-"]::before {
  content: ""; display: inline-block; width: 7px; height: 7px; margin-right: 6px; border-radius: 50%;
  background: currentColor; vertical-align: 1px;
}
.practice-num { font-family: var(--mono); border-radius: 8px; }

/* ---------- Telegram full screen (the whole app opens in it) ----------
   Keep content clear of the phone's status bar and Telegram's Close / ⋯ buttons, which float
   over the page. telegram-web-app.js keeps these --tg-* variables up to date. */
:root {
  --tg-top: calc(var(--tg-safe-area-inset-top, 0px) + var(--tg-content-safe-area-inset-top, 0px));
  --tg-bottom: max(env(safe-area-inset-bottom), var(--tg-safe-area-inset-bottom, 0px));
}
body.tg-fullscreen #topbar { padding-top: calc(10px + var(--tg-top)); }
body.tg-fullscreen #topbar[hidden] + main { padding-top: calc(20px + var(--tg-top)); }
body.tg-fullscreen.focus main { padding-top: calc(76px + var(--tg-top)); }
body.tg-fullscreen #focus-bar { top: calc(12px + var(--tg-top)); }
body.tg-fullscreen #tabs { bottom: calc(10px + var(--tg-bottom)); }
body.tg-fullscreen:not(.focus) main { padding-bottom: calc(104px + var(--tg-bottom)); }
body.tg-fullscreen .chat-input { bottom: calc(84px + var(--tg-bottom)); }