/* ЕГЭ-тренажёр — в духе Apple: системный шрифт, стекло, крупные заголовки, карточки. Тёмная тема по умолчанию. */
:root {
  --bg: #f5f5f7;
  --bg-elev: #ffffff;
  --bg-elev-2: #f2f2f7;
  --bg-elev-3: #e8e8ed;
  --text: #1d1d1f;
  --text-2: #6e6e73;
  --text-3: #86868b;
  --sep: rgba(0, 0, 0, 0.08);
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --accent-soft: rgba(0, 113, 227, 0.1);
  --green: #248a3d;
  --green-soft: rgba(52, 199, 89, 0.14);
  --red: #d70015;
  --red-soft: rgba(255, 59, 48, 0.12);
  --orange: #c93400;
  --yellow: #b25000;
  --nav: rgba(250, 250, 252, 0.72);
  --shadow: 0 2px 6px rgba(0, 0, 0, 0.04), 0 12px 32px rgba(0, 0, 0, 0.06);
  --code-bg: #f5f5f7;
  --radius: 22px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Inter", "Segoe UI", Roboto, sans-serif;
  --mono: "SF Mono", ui-monospace, "JetBrains Mono", Menlo, Consolas, monospace;
  color-scheme: light;
}
:root[data-theme="dark"] {
  --bg: #000000;
  --bg-elev: #1c1c1e;
  --bg-elev-2: #2c2c2e;
  --bg-elev-3: #3a3a3c;
  --text: #f5f5f7;
  --text-2: #a1a1a6;
  --text-3: #6e6e73;
  --sep: rgba(255, 255, 255, 0.08);
  --accent: #0a84ff;
  --accent-hover: #409cff;
  --accent-soft: rgba(10, 132, 255, 0.16);
  --green: #30d158;
  --green-soft: rgba(48, 209, 88, 0.14);
  --red: #ff453a;
  --red-soft: rgba(255, 69, 58, 0.14);
  --orange: #ff9f0a;
  --yellow: #ffd60a;
  --nav: rgba(22, 22, 23, 0.72);
  --shadow: none;
  --code-bg: #111113;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text); font-family: var(--font);
  font-size: 17px; line-height: 1.47; letter-spacing: -0.01em; -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}
a { color: var(--accent); text-decoration: none; }
button { font: inherit; }

/* ---------- навигация ---------- */
.nav {
  position: sticky; top: 0; z-index: 20; background: var(--nav);
  backdrop-filter: saturate(180%) blur(20px); -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--sep);
}
.nav-inner { max-width: 1040px; margin: 0 auto; padding: 0 16px; height: 52px; display: flex; align-items: center; gap: 16px; }
.brand { display: flex; align-items: center; gap: 8px; color: var(--text); font-weight: 600; font-size: 17px; }
.brand-mark { background: var(--accent); color: #fff; border-radius: 8px; padding: 2px 7px; font-size: 13px; font-weight: 700; letter-spacing: 0.02em; }
.brand-text { color: var(--text-2); font-weight: 500; }
.tabs { display: flex; gap: 4px; margin-left: auto; overflow-x: auto; scrollbar-width: none; }
.tabs::-webkit-scrollbar { display: none; }
.tabs a { color: var(--text-2); font-size: 14px; padding: 6px 12px; border-radius: 999px; white-space: nowrap; transition: color .2s, background .2s; }
.tabs a:hover { color: var(--text); }
.tabs a.active { color: var(--text); background: var(--bg-elev-2); }
.icon-btn { background: none; border: 0; color: var(--text-2); width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center; cursor: pointer; flex: none; }
.icon-btn:hover { background: var(--bg-elev-2); color: var(--text); }

/* ---------- раскладка ---------- */
.container { max-width: 1040px; margin: 0 auto; padding: 32px 16px 96px; }
.hero { margin: 8px 0 28px; }
.eyebrow { color: var(--accent); font-size: 14px; font-weight: 600; letter-spacing: 0; margin-bottom: 6px; }
h1.large { font-size: clamp(34px, 6vw, 56px); line-height: 1.07; letter-spacing: -0.03em; font-weight: 700; margin: 0; }
h2 { font-size: 28px; letter-spacing: -0.02em; margin: 40px 0 16px; font-weight: 700; }
h3 { font-size: 21px; letter-spacing: -0.015em; margin: 0 0 8px; font-weight: 600; }
.subtitle { color: var(--text-2); font-size: clamp(19px, 2.4vw, 24px); line-height: 1.3; margin-top: 10px; font-weight: 500; letter-spacing: -0.015em; }
.muted { color: var(--text-2); }
.small { font-size: 14px; }
.grid { display: grid; gap: 16px; }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.spacer { flex: 1; }

/* ---------- карточки ---------- */
.card { background: var(--bg-elev); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); border: 1px solid var(--sep); }
.card.tight { padding: 18px 20px; }
.card + .card { margin-top: 16px; }
.grid > .card + .card { margin-top: 0; }  /* в сетке отступы задаёт gap, иначе карточки съезжают */
.card.success { background: linear-gradient(0deg, var(--green-soft), var(--green-soft)), var(--bg-elev); border-color: transparent; }
.card.fail { background: linear-gradient(0deg, var(--red-soft), var(--red-soft)), var(--bg-elev); border-color: transparent; }
.card-link { display: block; color: inherit; transition: transform .2s ease; }
.card-link:hover { transform: translateY(-2px); }

/* ---------- кнопки ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  background: var(--accent); color: #fff; border: 0; border-radius: 999px;
  padding: 12px 22px; font-size: 17px; font-weight: 500; cursor: pointer; transition: background .2s, transform .1s, opacity .2s;
}
.btn:hover { background: var(--accent-hover); }
.btn:active { transform: scale(0.98); }
.btn:disabled { opacity: .45; cursor: default; }
.btn.secondary { background: var(--bg-elev-2); color: var(--text); }
.btn.secondary:hover { background: var(--bg-elev-3); }
.btn.ghost { background: transparent; color: var(--accent); padding: 12px 14px; }
.btn.ghost:hover { background: var(--accent-soft); }
.btn.small { padding: 8px 16px; font-size: 15px; }
.btn.big { padding: 16px 28px; font-size: 19px; }

/* сегментированный переключатель */
.segmented { display: inline-flex; background: var(--bg-elev-2); border-radius: 10px; padding: 2px; }
.segmented button { border: 0; background: transparent; color: var(--text); padding: 6px 16px; border-radius: 8px; font-size: 14px; font-weight: 500; cursor: pointer; }
.segmented button.on { background: var(--bg-elev); box-shadow: 0 1px 3px rgba(0,0,0,.18); }
:root[data-theme="dark"] .segmented button.on { background: var(--bg-elev-3); }

.chips { display: flex; gap: 8px; flex-wrap: wrap; }
.chip { border: 1px solid var(--sep); background: var(--bg-elev-2); color: var(--text); border-radius: 999px; padding: 7px 14px; font-size: 15px; cursor: pointer; transition: all .15s; }
.chip:hover { border-color: var(--text-3); }
.chip.on { background: var(--accent); color: #fff; border-color: transparent; }
.chips.shake { animation: shake .35s; }
@keyframes shake { 25% { transform: translateX(-6px); } 75% { transform: translateX(6px); } }

/* ---------- прогноз ---------- */
.stat { font-size: clamp(48px, 9vw, 80px); font-weight: 700; letter-spacing: -0.04em; line-height: 1; }
.stat small { font-size: .35em; color: var(--text-2); font-weight: 600; letter-spacing: -0.01em; }
.bar { height: 8px; background: var(--bg-elev-2); border-radius: 999px; overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--accent); border-radius: 999px; transition: width .6s cubic-bezier(.2,.8,.2,1); }
.bar.green > i { background: var(--green); }
.ring { --p: 0; width: 56px; height: 56px; border-radius: 50%; flex: none; display: grid; place-items: center; font-size: 14px; font-weight: 600;
  background: radial-gradient(closest-side, var(--bg-elev) 78%, transparent 80% 100%), conic-gradient(var(--c, var(--accent)) calc(var(--p) * 1%), var(--bg-elev-2) 0); }

/* статус навыков */
.skill { display: flex; align-items: center; gap: 10px; padding: 8px 0; border-bottom: 1px solid var(--sep); font-size: 15px; }
.skill:last-child { border-bottom: 0; }
.dot { width: 10px; height: 10px; border-radius: 50%; flex: none; background: var(--bg-elev-3); }
.dot.mastered { background: var(--green); }
.dot.shaky { background: var(--yellow); }
.dot.gap { background: var(--red); }
.dot.misconception { background: var(--orange); box-shadow: 0 0 0 3px rgba(255,159,10,.25); }
.legend { display: flex; gap: 16px; flex-wrap: wrap; font-size: 13px; color: var(--text-2); }
.legend span { display: inline-flex; align-items: center; gap: 6px; }

/* ---------- задание ---------- */
.task-head { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; flex-wrap: wrap; }
.badge { background: var(--accent-soft); color: var(--accent); border-radius: 999px; padding: 4px 12px; font-size: 13px; font-weight: 600; }
.badge.gray { background: var(--bg-elev-2); color: var(--text-2); }
.prompt { white-space: pre-wrap; font-size: 18px; line-height: 1.55; }
.instruction { color: var(--text-2); font-size: 15px; margin-bottom: 10px; }
.answer-row { display: flex; gap: 10px; margin-top: 22px; flex-wrap: wrap; }
.input {
  flex: 1; min-width: 180px; background: var(--bg-elev-2); border: 1px solid transparent; color: var(--text);
  border-radius: 14px; padding: 13px 16px; font-size: 18px; outline: none; transition: border-color .2s, box-shadow .2s;
}
.input:focus { border-color: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); }
textarea.input { font-family: var(--font); resize: vertical; min-height: 52px; }
.options { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 10px; margin-top: 20px; }
.option { background: var(--bg-elev-2); border: 1px solid var(--sep); color: var(--text); border-radius: 14px; padding: 14px; font-size: 18px; cursor: pointer; transition: all .15s; }
.option:hover { border-color: var(--accent); }
.progress-line { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; color: var(--text-2); font-size: 14px; }
.progress-line .bar { flex: 1; }

.tease { font-size: 22px; font-weight: 600; letter-spacing: -0.015em; margin-bottom: 6px; }
.result-answer { font-size: 17px; }
.result-answer b { font-family: var(--mono); font-size: 18px; }
ol.steps { margin: 12px 0 0; padding-left: 22px; }
ol.steps li { margin: 4px 0; }
.why { list-style: none; padding: 0; margin: 12px 0 0; }
.why li { padding: 6px 0; display: flex; gap: 8px; }

details { margin-top: 14px; }
details > summary { cursor: pointer; color: var(--accent); font-weight: 500; list-style: none; }
details > summary::-webkit-details-marker { display: none; }
details > summary::before { content: "›"; display: inline-block; margin-right: 8px; transition: transform .2s; }
details[open] > summary::before { transform: rotate(90deg); }
.rule { white-space: pre-wrap; color: var(--text-2); font-size: 15px; margin-top: 10px; }

pre, code { font-family: var(--mono); }
pre.code { background: var(--code-bg); border-radius: 14px; padding: 16px; overflow-x: auto; font-size: 14px; line-height: 1.5; margin: 10px 0 0; border: 1px solid var(--sep); }
.md p { margin: 0 0 10px; }
.md ul, .md ol { margin: 0 0 10px; padding-left: 22px; }
.md code { background: var(--bg-elev-2); border-radius: 6px; padding: 1px 6px; font-size: .9em; }
.md pre { background: var(--code-bg); border-radius: 14px; padding: 14px 16px; overflow-x: auto; border: 1px solid var(--sep); }
.md pre code { background: none; padding: 0; }

/* чат по объяснению */
.chat { margin-top: 16px; display: flex; flex-direction: column; gap: 10px; }
.bubble { max-width: 88%; padding: 10px 14px; border-radius: 18px; font-size: 16px; }
.bubble.me { align-self: flex-end; background: var(--accent); color: #fff; border-bottom-right-radius: 6px; }
.bubble.bot { align-self: flex-start; background: var(--bg-elev-2); border-bottom-left-radius: 6px; }
.bubble.bot .md p:last-child { margin-bottom: 0; }
.chat-input { display: flex; gap: 8px; margin-top: 12px; }
.typing { display: inline-flex; gap: 4px; padding: 14px 16px; }
.typing i { width: 7px; height: 7px; border-radius: 50%; background: var(--text-3); animation: blink 1.2s infinite; }
.typing i:nth-child(2) { animation-delay: .2s; } .typing i:nth-child(3) { animation-delay: .4s; }
@keyframes blink { 0%, 80%, 100% { opacity: .25; } 40% { opacity: 1; } }

/* ---------- редактор ---------- */
.editor-card { padding: 0; overflow: hidden; }
.editor-bar { display: flex; align-items: center; gap: 10px; padding: 10px 14px; border-bottom: 1px solid var(--sep); background: var(--bg-elev); }
.editor-bar .title { font-weight: 600; font-size: 15px; }
.traffic { display: flex; gap: 6px; }
.traffic i { width: 12px; height: 12px; border-radius: 50%; background: #ff5f57; } .traffic i:nth-child(2) { background: #febc2e; } .traffic i:nth-child(3) { background: #28c840; }
.CodeMirror { height: auto; min-height: 220px; font-family: var(--mono); font-size: 15px; line-height: 1.55; background: var(--code-bg); color: var(--text); }
.CodeMirror-scroll { min-height: 220px; max-height: 520px; }
.CodeMirror-gutters { background: var(--code-bg); border-right: 1px solid var(--sep); }
.CodeMirror-linenumber { color: var(--text-3); }
.CodeMirror-cursor { border-left: 2px solid var(--accent); }
.CodeMirror-selected, .CodeMirror-focused .CodeMirror-selected { background: var(--accent-soft) !important; }
.cm-s-default .cm-keyword { color: #ff7ab2; font-weight: 600; }
.cm-s-default .cm-def { color: #6bdfff; }
.cm-s-default .cm-builtin { color: #dabaff; }
.cm-s-default .cm-string { color: #ff8170; }
.cm-s-default .cm-number { color: #d9c97c; }
.cm-s-default .cm-comment { color: #7f8c98; font-style: italic; }
.cm-s-default .cm-variable { color: var(--text); }
.cm-s-default .cm-operator { color: var(--text); }
:root:not([data-theme="dark"]) .cm-s-default .cm-keyword { color: #ad3da4; }
:root:not([data-theme="dark"]) .cm-s-default .cm-def { color: #0f68a0; }
:root:not([data-theme="dark"]) .cm-s-default .cm-builtin { color: #804fb8; }
:root:not([data-theme="dark"]) .cm-s-default .cm-string { color: #d12f1b; }
:root:not([data-theme="dark"]) .cm-s-default .cm-number { color: #272ad8; }
:root:not([data-theme="dark"]) .cm-s-default .cm-comment { color: #707f8c; }
.console { background: var(--code-bg); border-top: 1px solid var(--sep); font-family: var(--mono); font-size: 14px; padding: 12px 16px; min-height: 44px; max-height: 260px; overflow: auto; white-space: pre-wrap; color: var(--text-2); }
.console.err { color: var(--red); }
.console.ok { color: var(--text); }

/* ---------- монеты и ставки ---------- */
.coin { display: inline-block; width: .95em; height: .95em; border-radius: 50%; vertical-align: -0.12em; flex: none;
  background: radial-gradient(circle at 35% 30%, #fff3b0 0 18%, #ffd60a 19% 55%, #e0a800 56% 100%);
  box-shadow: inset 0 0 0 .08em #c98f00, 0 .05em .1em rgba(0,0,0,.25); }
.coins { color: var(--text); background: var(--bg-elev-2); border-radius: 999px; padding: 5px 12px; font-size: 14px; white-space: nowrap; flex: none; }
.coins b { font-variant-numeric: tabular-nums; }
.coins.bump { animation: bump .6s ease; }
@keyframes bump { 30% { transform: scale(1.18); } }
.bet-chip { display: inline-flex; flex-direction: column; align-items: center; gap: 2px; min-width: 92px; padding: 9px 14px; border-radius: 16px; }
.bet-chip small { font-size: 12px; color: var(--text-2); font-variant-numeric: tabular-nums; }
.bet-chip.on small { color: rgba(255,255,255,.85); }
.bet-chip:disabled { opacity: .35; cursor: default; }
.bets-locked .bet-chip { pointer-events: none; }
.coin-delta { display: inline-block; font-weight: 700; font-size: 20px; margin-left: 10px; font-variant-numeric: tabular-nums; animation: pop .5s cubic-bezier(.2,.9,.3,1.4) both; }
.coin-delta.plus { color: var(--green); } .coin-delta.minus { color: var(--red); } .coin-delta.zero { color: var(--text-2); }
@keyframes pop { from { opacity: 0; transform: translateY(8px) scale(.8); } to { opacity: 1; transform: none; } }
.honesty-row { display: flex; align-items: center; gap: 12px; padding: 8px 0; border-bottom: 1px solid var(--sep); font-size: 15px; }
.honesty-row:last-child { border-bottom: 0; }
.honesty-row .bar { flex: 1; }
.honesty-row .lbl { width: 128px; flex: none; }
.honesty-row .val { width: 120px; flex: none; text-align: right; color: var(--text-2); font-size: 14px; }
@media (max-width: 640px) { .honesty-row .lbl { width: 104px; } .honesty-row .val { width: 92px; } .bet-chip { min-width: 0; flex: 1 1 40%; } }

/* ---------- теория ---------- */
.card.accent { background: linear-gradient(135deg, var(--accent-soft), transparent 70%), var(--bg-elev); border-color: var(--accent-soft); }
.theory-step { display: flex; gap: 14px; align-items: flex-start; }
.theory-step .lesson-num { margin-top: 2px; }
.md table { border-collapse: collapse; width: 100%; margin: 4px 0 12px; font-size: 15px; }
.md th, .md td { border-bottom: 1px solid var(--sep); padding: 8px 10px; text-align: left; vertical-align: top; }
.md th { color: var(--text-2); font-weight: 600; }
.quiz-row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 10px; }
.quiz-row .input { max-width: 220px; }
.quiz-mark { font-size: 15px; }
.trap { display: flex; gap: 10px; padding: 8px 0; border-bottom: 1px solid var(--sep); }
.trap:last-child { border-bottom: 0; }

/* ---------- уроки ---------- */
.lesson-item { display: flex; align-items: center; gap: 14px; }
.lesson-num { width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center; background: var(--bg-elev-2); font-weight: 600; flex: none; }
.lesson-num.done { background: var(--green); color: #fff; }
.lesson-text { white-space: pre-wrap; color: var(--text); }

/* ---------- чат по странице ---------- */
.fab { position: fixed; right: 20px; bottom: 20px; z-index: 40; border: 0; cursor: pointer; border-radius: 999px;
  padding: 13px 20px; font-size: 16px; font-weight: 600; color: #fff; background: var(--accent);
  box-shadow: 0 10px 30px rgba(10,132,255,.35); transition: transform .15s; }
.fab:hover { transform: translateY(-2px); }
.fab.has-quote { background: var(--text); color: var(--bg); box-shadow: 0 10px 30px rgba(0,0,0,.35); animation: bump .5s ease; }
.chat-sheet { position: fixed; right: 20px; bottom: 20px; z-index: 45; width: min(420px, calc(100vw - 32px)); height: min(640px, calc(100vh - 100px));
  display: flex; flex-direction: column; background: var(--nav); backdrop-filter: saturate(180%) blur(24px); -webkit-backdrop-filter: saturate(180%) blur(24px);
  border: 1px solid var(--sep); border-radius: 22px; box-shadow: 0 24px 60px rgba(0,0,0,.45); overflow: hidden; animation: sheet .25s cubic-bezier(.2,.8,.2,1); }
@keyframes sheet { from { opacity: 0; transform: translateY(16px) scale(.98); } to { opacity: 1; transform: none; } }
.chat-sheet[hidden], .fab[hidden], .sel-ask[hidden], .sheet-quote[hidden] { display: none; }
.sheet-head { display: flex; align-items: center; gap: 10px; padding: 14px 16px; border-bottom: 1px solid var(--sep); }
.sheet-head > div { flex: 1; min-width: 0; }
.sheet-body { flex: 1; overflow-y: auto; padding: 14px 16px; }
.sheet-body .chat { margin-top: 0; }
.sheet-quote { display: flex; gap: 8px; align-items: flex-start; margin: 0 12px; padding: 8px 10px 8px 12px; border-left: 3px solid var(--accent);
  background: var(--accent-soft); border-radius: 10px; font-size: 14px; color: var(--text-2); }
.sheet-quote span { flex: 1; max-height: 64px; overflow: hidden; }
.sheet-quote .icon-btn { width: 24px; height: 24px; font-size: 12px; }
.sheet-input { display: flex; gap: 8px; padding: 12px; }
.sheet-input .input { min-width: 0; resize: none; max-height: 120px; font-size: 16px; padding: 11px 14px; }
.sheet-input .btn { padding: 0 18px; }
.bubble .quote { display: block; font-size: 13px; opacity: .85; border-left: 2px solid rgba(255,255,255,.6); padding-left: 8px; margin-bottom: 6px; }
.sel-ask { position: fixed; z-index: 50; border: 0; cursor: pointer; border-radius: 999px; padding: 8px 14px; font-size: 14px; font-weight: 600;
  background: var(--text); color: var(--bg); box-shadow: 0 8px 24px rgba(0,0,0,.35); transform: translateX(-50%); white-space: nowrap; }
@media (max-width: 640px) {
  .chat-sheet { right: 0; left: 0; bottom: 0; width: 100%; height: 82vh; border-radius: 22px 22px 0 0; }
  .fab { right: 16px; bottom: 16px; }
}

/* ---------- прочее ---------- */
.toast { position: fixed; left: 50%; bottom: 28px; transform: translate(-50%, 20px); background: var(--bg-elev-3); color: var(--text); padding: 12px 20px; border-radius: 999px; font-size: 15px; opacity: 0; pointer-events: none; transition: all .3s; z-index: 50; box-shadow: 0 8px 30px rgba(0,0,0,.3); max-width: calc(100% - 32px); text-align: center; }
.toast.show { opacity: 1; transform: translate(-50%, 0); }
.center { text-align: center; }
.empty { padding: 60px 0; }
.spinner { width: 28px; height: 28px; border: 3px solid var(--bg-elev-3); border-top-color: var(--accent); border-radius: 50%; animation: spin .8s linear infinite; margin: 40px auto; }
@keyframes spin { to { transform: rotate(360deg); } }
.fade-in { animation: fade .35s ease both; }
@keyframes fade { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
hr.sep { border: 0; border-top: 1px solid var(--sep); margin: 18px 0; }

@media (max-width: 640px) {
  .container { padding: 20px 16px 80px; }
  .card { padding: 18px; border-radius: 18px; }
  .brand-text { display: none; }
  .prompt { font-size: 16px; }
  h2 { font-size: 24px; margin-top: 32px; }
  .btn.big { width: 100%; }
}