/* Colors come from Telegram's theme (--tg-theme-*), set by telegram-web-app.js.
   The fallbacks are for a plain browser during local development. */
:root {
  --fb-bg: #ffffff;
  --fb-card: #f2f2f6;
  --fb-text: #111111;
  --fb-hint: #8a8a8e;
  --fb-link: #2481cc;
  --fb-button: #2481cc;
  --fb-button-text: #ffffff;
  --bg: var(--tg-theme-bg-color, var(--fb-bg));
  --card: var(--tg-theme-secondary-bg-color, var(--fb-card));
  --text: var(--tg-theme-text-color, var(--fb-text));
  --hint: var(--tg-theme-hint-color, var(--fb-hint));
  --link: var(--tg-theme-link-color, var(--fb-link));
  --button: var(--tg-theme-button-color, var(--fb-button));
  --button-text: var(--tg-theme-button-text-color, var(--fb-button-text));
  --ok: #2e9e4f;
  --bad: #d64545;
  --warn: #c98a00;
}
@media (prefers-color-scheme: dark) {
  :root {
    --fb-bg: #17212b;
    --fb-card: #232e3c;
    --fb-text: #f5f5f5;
    --fb-hint: #708499;
    --fb-link: #6ab3f3;
    --fb-button: #5288c1;
  }
}
html { color-scheme: light dark; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
main { padding: 16px 16px 32px; max-width: 640px; margin: 0 auto; }
h1 { font-size: 22px; margin: 8px 0 12px; }
h2 { font-size: 17px; margin: 0 0 8px; }
a { color: var(--link); }
code { font-size: 14px; }
.muted { color: var(--hint); font-size: 14px; }
.error { color: var(--bad); }
/* A failed request (glue.js §8): pinned above the page, out of htmx's way. */
.trouble { position: sticky; top: 0; z-index: 10; margin: 0; padding: 12px 16px; background: var(--card);
           border-bottom: 2px solid var(--bad); display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.trouble[hidden] { display: none; }
.trouble p { margin: 0; flex: 1 1 100%; }
.trouble button { border: 0; border-radius: 8px; padding: 8px 14px; font-size: 15px; background: var(--button); color: var(--button-text); }
.trouble button[hidden] { display: none; }
/* The demo bar of local development (shell.html, glue.js §10). */
.demo { position: fixed; left: 0; right: 0; bottom: 0; z-index: 20; padding: 8px 12px 10px; background: var(--card);
        border-top: 2px dashed var(--warn); font-size: 14px; }
.demo button { margin: 2px; padding: 5px 10px; border: 1px solid var(--hint); border-radius: 8px; background: var(--bg); color: var(--text); font: inherit; }
.demo button.active { background: var(--button); border-color: var(--button); color: var(--button-text); }
.demo p { margin: 4px 0 0; color: var(--hint); }
.demo p button { padding: 2px 8px; }
body.has-demo main { padding-bottom: 130px; }
/* While a request is in flight its buttons can't be tapped again. */
.htmx-request button, button.htmx-request { opacity: 0.6; pointer-events: none; }
.ok { color: var(--ok); font-weight: 600; }
.bad { color: var(--bad); font-weight: 600; }
.hint { color: var(--warn); }
.card { background: var(--card); border-radius: 12px; padding: 12px 14px; margin: 12px 0; }
.button {
  display: inline-block; box-sizing: border-box;
  background: var(--button); color: var(--button-text);
  border: 0; border-radius: 10px; padding: 12px 16px;
  font: inherit; font-weight: 600; text-align: center; text-decoration: none; cursor: pointer;
}
.button.wide { display: block; width: 100%; }
.button.danger { background: var(--bad); color: #fff; }
.delete-link { margin-top: 32px; text-align: center; }
.delete-link a { color: var(--hint); }

/* Math: three fonts side by side for the device check. */
@font-face { font-family: "Noto Sans Math nef"; src: url("/static/fonts/NotoSansMath-nef.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "NewCM Math nef"; src: url("/static/fonts/NewCMMath-nef.woff2") format("woff2"); font-display: swap; }
/* Full-size fractions inside text, as on the printed exam: TeX's inline default
   shrinks them to script size, which is unreadable on a phone. */
math { font-size: 1.15em; math-style: normal; }
.font-system math { font-family: math; }
.font-noto math { font-family: "Noto Sans Math nef", math; }
.font-newcm math { font-family: "NewCM Math nef", math; }
.sample { padding: 8px 0; border-top: 1px solid color-mix(in srgb, var(--hint) 30%, transparent); }
.sample .label { font-size: 13px; color: var(--hint); margin-bottom: 4px; }
.variant { display: flex; align-items: center; gap: 10px; min-height: 36px; overflow-x: auto; }
.tag { flex: none; width: 20px; font-size: 12px; color: var(--hint); }

.figure svg { display: block; width: 100%; max-width: 320px; height: auto; margin: 8px auto; color: var(--text); }

/* Answer input with an on-screen keypad. */
.answer {
  width: 100%; box-sizing: border-box;
  font-size: 24px; padding: 10px 12px; text-align: center;
  border-radius: 10px; border: 1px solid var(--hint);
  background: var(--bg); color: var(--text);
}
.keypad { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin: 10px 0; }
/* Keys stand out from the page and from a card, in light and dark themes. */
.keypad button { font-size: 22px; padding: 12px 0; border-radius: 10px; border: 1px solid color-mix(in srgb, var(--hint) 45%, transparent); background: var(--card); color: var(--text); touch-action: manipulation; }
.keypad button:active { background: color-mix(in srgb, var(--button) 20%, var(--card)); }
.keypad .submit { grid-column: span 2; font-size: 17px; background: var(--button); color: var(--button-text); border-color: var(--button); }

.swatches { display: flex; flex-wrap: wrap; gap: 6px; }
.swatch { width: 28px; height: 28px; border-radius: 6px; border: 1px solid var(--hint); }
label.check { display: flex; gap: 8px; align-items: flex-start; margin: 8px 0; }
label.field { display: block; margin: 12px 0; }
select, textarea {
  display: block; width: 100%; box-sizing: border-box; margin-top: 6px;
  font: inherit; border-radius: 10px; padding: 8px;
  background: var(--bg); color: var(--text); border: 1px solid var(--hint);
}
textarea { min-height: 64px; margin-bottom: 12px; }

/* App screens */
.tabs { display: flex; gap: 4px; margin: -4px 0 12px; border-bottom: 1px solid color-mix(in srgb, var(--hint) 30%, transparent); }
.tabs a { flex: 1; text-align: center; padding: 10px 4px; color: var(--hint); text-decoration: none; font-weight: 600; font-size: 15px; border-bottom: 2px solid transparent; }
.tabs a.active { color: var(--text); border-bottom-color: var(--button); }
.notice { background: color-mix(in srgb, var(--button) 15%, transparent); border-radius: 10px; padding: 10px 12px; }
.card-title { font-weight: 700; margin-bottom: 4px; }
.link-card { display: block; color: inherit; text-decoration: none; }
.back { display: inline-block; margin: 4px 0; color: var(--link); text-decoration: none; }
.stack { display: grid; gap: 10px; }
.choice { display: block; width: 100%; text-align: left; padding: 14px; border-radius: 12px; border: 1px solid color-mix(in srgb, var(--hint) 40%, transparent); background: var(--card); color: var(--text); font: inherit; cursor: pointer; }
.choice strong { display: block; font-size: 17px; margin-bottom: 2px; }
.choice span { color: var(--hint); font-size: 14px; }
.bar { height: 6px; border-radius: 3px; background: color-mix(in srgb, var(--hint) 25%, transparent); overflow: hidden; margin: 6px 0 12px; }
.bar span { display: block; height: 100%; background: var(--button); }
.button.secondary { background: color-mix(in srgb, var(--button) 15%, transparent); color: var(--link); }
.link-button { background: none; border: 0; padding: 8px 0; color: var(--link); font: inherit; cursor: pointer; }
.link-button.danger { color: var(--bad); }

/* Practice: task numbers */
.numbers { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 8px; }
.numbers form { margin: 0; }
.number { display: flex; flex-direction: column; gap: 2px; width: 100%; height: 100%; box-sizing: border-box; padding: 10px; border-radius: 12px; border: 0; background: var(--card); color: var(--text); font: inherit; text-align: left; cursor: pointer; }
.number b { font-size: 20px; }
a.number { text-decoration: none; }
.number span { font-size: 13px; color: var(--hint); }
.number.disabled { opacity: 0.5; cursor: default; }
.number em { font-size: 12px; font-style: normal; color: var(--hint); }

/* Solving */
.item-head { margin: 4px 0 10px; color: var(--hint); font-size: 14px; }
.badge { display: inline-block; background: var(--button); color: var(--button-text); border-radius: 6px; padding: 1px 7px; font-weight: 700; margin-right: 4px; }
.statement { font-size: 17px; line-height: 1.55; margin-bottom: 12px; }
.statement math[display="block"], .solution math[display="block"] { margin: 8px 0; overflow-x: auto; overflow-y: hidden; }
/* A long display formula comes cut into pieces that wrap on narrow screens. */
.math-lines { display: block; margin: 8px 0; text-align: center; }
.nowrap { white-space: nowrap; }
.result { border-radius: 10px; padding: 10px 12px; margin: 12px 0; }
.ok-box { background: color-mix(in srgb, var(--ok) 15%, transparent); }
.bad-box { background: color-mix(in srgb, var(--bad) 13%, transparent); }
.solution { background: var(--card); border-radius: 12px; padding: 12px 14px; line-height: 1.55; }
.actions { display: grid; gap: 8px; margin-top: 12px; }
.actions form { margin: 0; }
.keypad .button.submit { padding: 12px 0; }

/* Teacher: invite and results */
.link-text { word-break: break-all; font-size: 14px; background: var(--bg); border-radius: 8px; padding: 8px; }
.qr { display: flex; justify-content: center; margin: 10px 0; }
.qr svg { width: 176px; height: 176px; border-radius: 8px; }
.checks { display: grid; gap: 2px; margin-bottom: 8px; }
label.check.disabled { color: var(--hint); }
label.field input { display: block; width: 100%; box-sizing: border-box; margin-top: 6px; font: inherit; border-radius: 10px; padding: 10px; background: var(--bg); color: var(--text); border: 1px solid var(--hint); }
.table-wrap { overflow-x: auto; }
table.results, table.stats { border-collapse: collapse; width: 100%; font-size: 14px; }
.results th, .results td, .stats th, .stats td { padding: 6px 6px; text-align: center; border-bottom: 1px solid color-mix(in srgb, var(--hint) 20%, transparent); white-space: nowrap; }
.results tbody th { text-align: left; font-weight: 600; max-width: 140px; overflow: hidden; text-overflow: ellipsis; }
.stats td:nth-child(2), .stats th:nth-child(2) { text-align: left; white-space: normal; }
.c-good { color: var(--ok); font-weight: 700; }
.c-mid { color: var(--warn); font-weight: 700; }
.c-part { color: var(--link); }
.c-none { color: var(--hint); }
.member { display: flex; justify-content: space-between; align-items: center; border-bottom: 1px solid color-mix(in srgb, var(--hint) 20%, transparent); }
.member form { margin: 0; }
main ul { padding-left: 20px; }

/* M2: assignments, reports, parent links */
h2.section { font-size: 17px; margin: 18px 0 4px; }
.counts { display: grid; gap: 6px; margin-bottom: 8px; }
.count { display: flex; justify-content: space-between; align-items: center; gap: 8px; }
.count span { font-size: 14px; }
.count select { width: auto; margin: 0; min-width: 64px; }
input[type="date"] { display: block; width: 100%; box-sizing: border-box; margin-top: 6px; font: inherit; border-radius: 10px; padding: 8px; background: var(--bg); color: var(--text); border: 1px solid var(--hint); }
.member-block { border-bottom: 1px solid color-mix(in srgb, var(--hint) 20%, transparent); padding-bottom: 4px; }
.member-block .member { border-bottom: 0; }
.member-block form { margin: 0; }
.parent-link { margin: 4px 0 8px; }
details.report { margin-top: 18px; color: var(--hint); font-size: 14px; }
details.report summary { cursor: pointer; padding: 6px 0; }
details.report textarea { margin-top: 8px; }

/* Teacher: names, a student's answers */
.results td a, .results th a, .member a, .homework td a { color: inherit; text-decoration: underline; text-underline-offset: 2px; }
.c-bad { color: var(--bad); font-weight: 700; }

/* A student's card: the daily sets of 14 days as dots */
.dots { display: flex; flex-wrap: wrap; gap: 4px; margin: 6px 0 10px; }
.dot { display: inline-block; width: 16px; height: 16px; border-radius: 50%; box-sizing: border-box; border: 2px solid currentColor; vertical-align: -3px; }
.dot.c-good { background: var(--ok); color: var(--ok); }
.dot.c-mid { background: var(--warn); color: var(--warn); }
.dot.c-part { background: linear-gradient(90deg, currentColor 50%, transparent 50%); color: var(--link); }
.dot.c-none { color: var(--hint); }
.dot.c-off { color: color-mix(in srgb, var(--hint) 40%, transparent); border-style: dashed; }
.dot.c-pre { color: color-mix(in srgb, var(--hint) 25%, transparent); border-style: dotted; }
.legend .dot { margin: 0 2px 0 6px; }
.homework td:first-child { text-align: left; white-space: normal; }
details.kinds-number { margin: 10px 0 0; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; margin: 8px 0 12px; }
.chip { padding: 4px 12px; border-radius: 14px; background: var(--card); color: var(--text); text-decoration: none; font-size: 14px; }
.chip.active { background: var(--button); color: var(--button-text); }
.quick { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; margin: 8px 0; }
.quick .button { padding-left: 4px; padding-right: 4px; }
details.kinds-number summary { font-weight: 600; cursor: pointer; }
.kind .actions { grid-template-columns: 1fr 1fr; }
.homework td:last-child { text-align: right; white-space: normal; }
details.rename summary, details.more summary { cursor: pointer; color: var(--link); padding: 6px 0; font-size: 15px; }
details.more { margin-top: 8px; }
.card .solution { background: var(--bg); }
.plain-box { background: color-mix(in srgb, var(--hint) 12%, transparent); }

/* «Вариант части 1»: its tasks by number, and its result. */
.steps { display: flex; flex-wrap: wrap; gap: 6px; margin: 10px 0; }
.step { min-width: 36px; padding: 6px 0; text-align: center; border-radius: 8px; border: 1px solid color-mix(in srgb, var(--hint) 40%, transparent); color: var(--text); text-decoration: none; font-weight: 600; }
.step.done { background: var(--button); border-color: var(--button); color: var(--button-text); }
.step.current { outline: 2px solid var(--link); outline-offset: 1px; }
.score { font-size: 22px; font-weight: 700; margin: 4px 0 8px; }
.exam-row { display: flex; flex-wrap: wrap; gap: 2px 8px; align-items: baseline; padding: 8px 0; border-bottom: 1px solid color-mix(in srgb, var(--hint) 20%, transparent); color: var(--text); text-decoration: none; }

/* «Цель недели»: the week on «Сегодня». */
.week { background: var(--card); border-radius: 12px; padding: 10px 14px; margin: 12px 0; }
.week.met { box-shadow: inset 0 0 0 2px var(--ok); }
.week p { margin: 8px 0 0; }
.week-days { display: flex; gap: 4px; }
.week-day { flex: 1; text-align: center; padding: 6px 0; border-radius: 8px; font-size: 13px; color: var(--hint); border: 1px solid color-mix(in srgb, var(--hint) 30%, transparent); }
.week-day.done { background: var(--ok); border-color: var(--ok); color: #fff; }
.week-day.today { border: 2px solid var(--link); color: var(--text); font-weight: 600; }
.week-day.future { opacity: 0.45; }
.day-closed .stamp { font-weight: 700; font-size: 18px; color: var(--ok); margin: 0 0 4px; }
@media (prefers-reduced-motion: no-preference) {
  .day-closed .stamp { animation: stamp 0.5s ease-out; }
}
@keyframes stamp { from { transform: scale(1.4); opacity: 0; } to { transform: scale(1); opacity: 1; } }
.level-up { font-weight: 700; color: var(--ok); }

/* «Уровни по номерам»: the 13 tiles. */
.levels { display: grid; grid-template-columns: repeat(auto-fill, minmax(84px, 1fr)); gap: 6px; margin: 8px 0 14px; }
.level { border-radius: 10px; padding: 6px 8px; background: var(--card); display: flex; flex-direction: column; gap: 2px; font-size: 13px; }
.level b { font-size: 17px; }
.level em { font-style: normal; font-size: 11px; color: var(--warn); }
.level.lv1 { box-shadow: inset 3px 0 0 color-mix(in srgb, var(--hint) 60%, transparent); }
.level.lv2 { box-shadow: inset 3px 0 0 var(--warn); }
.level.lv3 { box-shadow: inset 3px 0 0 var(--link); }
.level.lv4 { background: color-mix(in srgb, var(--ok) 22%, var(--card)); box-shadow: inset 3px 0 0 var(--ok); }
.level.off { opacity: 0.45; }
.level-detail { background: var(--card); border-radius: 12px; padding: 8px 12px; margin: 8px 0; }
.level-detail summary { cursor: pointer; }