:root {
  color-scheme: light;
  --bg: #f8f9fc;
  --card: #ffffff;
  --accent: #5b5cf0;
  --accent-ink: #3c3eb8;
  --accent-soft: #eef0ff;
  --lime: #c9f56b;
  --lime-ink: #24300a;
  --text: #191b2a;
  --muted: #777b90;
  --line: #e9eaf2;
  --mastered: #1c7c4a;
  --mastered-bg: #e7f6ee;
  --practice: #c56a12;
  --practice-bg: #fff3e6;
  --repeat: #d4534e;
  --repeat-bg: #fdeeee;
  --shadow: 0 10px 30px rgba(25, 27, 42, 0.05);
  --radius: 20px;
  --font: Inter, "Segoe UI", system-ui, sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
}

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.45;
}

button, input, textarea, select { font: inherit; color: inherit; }

button { cursor: pointer; }

img { max-width: 100%; display: block; }

h1, h2, p { overflow-wrap: anywhere; }

h1 {
  margin: 0;
  font-size: clamp(26px, 7vw, 34px);
  line-height: 1.12;
  letter-spacing: -0.03em;
}

h2 { margin: 0 0 8px; font-size: 18px; letter-spacing: -0.02em; }

p { margin: 0; }

a { color: inherit; }

::placeholder { color: #8b90a6; }

::selection { background: #e0e2ff; }

button:focus-visible,
a:focus-visible,
select:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.sr, .file input {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.icon { width: 22px; height: 22px; flex: 0 0 auto; }

.brand { display: inline-flex; align-items: center; gap: 8px; }

.mark {
  width: 22px;
  height: 22px;
  border-radius: 7px;
  background: var(--accent);
  position: relative;
}

.mark::after {
  content: "";
  position: absolute;
  width: 8px;
  height: 8px;
  border-radius: 3px;
  background: var(--lime);
  right: 3px;
  bottom: 3px;
}

.logo { font-weight: 700; letter-spacing: -0.04em; font-size: 18px; }

.page { padding: 8px 16px calc(92px + env(safe-area-inset-bottom)); }

.page-inner { width: min(640px, 100%); margin: 0 auto; }

.role-teacher .page-inner { width: min(1040px, 100%); }

.stack { display: flex; flex-direction: column; gap: 14px; }

.stack.tight { gap: 8px; }

.top, .app-bar, .row-between, .stat-line, .ask-actions, .actions, .wizard-nav, .dialog-actions, .bar-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.top, .app-bar, .row-between { justify-content: space-between; }

.top.compact { justify-content: flex-start; }

.app-bar { margin-bottom: 4px; }

.hello { margin: 2px 0 0; color: var(--muted); font-size: 15px; }

.hello strong { color: var(--text); }

.kicker, .hint, .side-note, .field-label {
  color: var(--muted);
  font-size: 13px;
  font-weight: 600;
}

.kicker { margin: 0; }

.hint { font-weight: 500; line-height: 1.4; }

.field-label { display: block; margin-bottom: 6px; }

.section-title { margin: 4px 0 0; font-size: 16px; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
}

.card-flat { box-shadow: none; }

.card-ask { border-radius: 24px; padding: 18px; }

.card-ask h1 { margin-bottom: 12px; }

.card-next {
  background: var(--lime);
  border-color: transparent;
  box-shadow: none;
}

.card-next h2, .card-next .kicker { color: var(--lime-ink); }

.card-link, .topic-row, .choice, .side-link {
  width: 100%;
  text-align: left;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.card-link, .topic-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  box-shadow: var(--shadow);
}

.topic-row strong, .card-link strong { display: block; }

.back .icon { transform: rotate(180deg); }

.pair { display: grid; grid-template-columns: 1.35fr 0.85fr; gap: 12px; }

.stat-grid, .topic-grid, .people { display: grid; gap: 12px; }

.stat-num {
  margin: 4px 0;
  font-size: 40px;
  line-height: 1;
  letter-spacing: -0.04em;
  font-weight: 700;
}

.stat-line { align-items: center; }

.ring-wrap { width: 72px; height: 72px; position: relative; flex: 0 0 auto; }

.ring { width: 72px; height: 72px; transform: rotate(-90deg); }

.ring-bg, .ring-fg { fill: none; stroke-width: 3.5; }

.ring-bg { stroke: #eceef5; }

.ring-fg { stroke: var(--accent); stroke-linecap: round; }

.ring-wrap strong {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-size: 15px;
}

.avatar {
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-weight: 700;
  display: grid;
  place-items: center;
}

.avatar-lg { width: 56px; height: 56px; border-radius: 18px; font-size: 20px; }

.class-pill {
  border: 1px solid var(--line);
  background: white;
  border-radius: 999px;
  min-height: 40px;
  padding: 0 14px;
  font-weight: 700;
}

.area, .field {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: white;
  padding: 14px 16px;
  font-size: 16px;
}

.area { min-height: 96px; resize: vertical; display: block; }

.field:focus, .area:focus, select.field:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.field-error { color: var(--repeat); font-size: 14px; font-weight: 600; margin: 0; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 0 16px;
  border-radius: 14px;
  border: 1px solid transparent;
  font-weight: 700;
  text-decoration: none;
  touch-action: manipulation;
}

.btn-primary { background: var(--accent); color: white; }

.btn-ghost { background: white; border-color: var(--line); color: var(--text); }

.btn-dark { background: var(--text); color: white; }

.btn-icon { width: 48px; padding: 0; background: white; border-color: var(--line); }

.btn:disabled { opacity: 0.55; cursor: default; }

.text-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  min-height: 44px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--accent-ink);
  font-weight: 700;
}

.ask-actions .btn-primary, .actions .btn, .wizard-nav .btn, .dialog-actions .btn, .actions-stack .btn { flex: 1; }

.actions, .wizard-nav, .dialog-actions { flex-wrap: wrap; }

@media (max-width: 420px) {
  .actions { flex-direction: column; }
  .actions .btn { width: 100%; }
}

.actions-stack { display: flex; flex-direction: column; gap: 8px; }

.actions-stack .btn { width: 100%; justify-content: flex-start; }

.file { position: relative; }

.attach {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px;
  border-radius: 14px;
  background: var(--accent-soft);
}

.thumb { width: 48px; height: 48px; object-fit: cover; border-radius: 12px; }

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border-radius: 999px;
  padding: 4px 10px;
  font-size: 13px;
  font-weight: 700;
  white-space: nowrap;
  background: #f1f2f7;
  color: var(--muted);
}

.pill::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: currentColor;
}

.pill[data-status="mastered"] { color: var(--mastered); background: var(--mastered-bg); }
.pill[data-status="needs_practice"] { color: var(--practice); background: var(--practice-bg); }
.pill[data-status="repeat"] { color: var(--repeat); background: var(--repeat-bg); }

.track {
  height: 8px;
  border-radius: 99px;
  background: #eceef5;
  overflow: hidden;
  flex: 1;
}

.track > span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
}

.track[data-status="mastered"] > span { background: var(--mastered); }
.track[data-status="needs_practice"] > span { background: var(--practice); }
.track[data-status="repeat"] > span { background: var(--repeat); }

.meter { display: flex; height: 8px; border-radius: 99px; overflow: hidden; background: #eceef5; }

.meter i { display: block; min-width: 4px; }

.meter i[data-status="mastered"] { background: var(--mastered); }
.meter i[data-status="needs_practice"] { background: var(--practice); }
.meter i[data-status="repeat"] { background: var(--repeat); }
.meter i[data-status="none"] { background: #e1e3ee; }

.stages {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.stages li {
  flex: 1;
  font-size: 12px;
  font-weight: 700;
  color: var(--muted);
  padding-top: 8px;
  border-top: 3px solid var(--line);
}

.stages .is-current { color: var(--accent-ink); border-color: var(--accent); }
.stages .is-done { color: var(--mastered); border-color: var(--mastered); }

.mode {
  margin: 0;
  border-radius: 14px;
  padding: 10px 12px;
  font-size: 14px;
  font-weight: 700;
}

.mode-training { background: var(--accent-soft); color: var(--accent-ink); }
.mode-submission { background: var(--repeat-bg); color: #8d3030; }

.segment {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
  padding: 4px;
  border-radius: 16px;
  background: #eef0f6;
}

.segment button {
  min-height: 44px;
  border: 0;
  border-radius: 12px;
  background: transparent;
  color: var(--muted);
  font-weight: 700;
}

.segment button.is-on { background: white; color: var(--text); box-shadow: 0 1px 2px rgba(25, 27, 42, 0.06); }

.chips { display: flex; flex-wrap: wrap; gap: 8px; }

.chip, .choice {
  min-height: 40px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: white;
  padding: 0 12px;
  font-weight: 700;
}

.choice { width: 100%; border-radius: 14px; text-align: left; }

.chip.is-on, .choice.is-on, .topic-card.is-on {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent-ink);
}

.check { display: flex; gap: 10px; align-items: flex-start; font-weight: 600; }

.check input { width: 20px; height: 20px; margin-top: 2px; accent-color: var(--accent); }

.banner {
  border-radius: 16px;
  padding: 12px 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.banner-info { background: var(--accent-soft); color: var(--accent-ink); }
.banner-warn { background: #fff6d8; color: #5c4b12; }
.banner-bad { background: var(--repeat-bg); color: #8d3030; }

.feedback.is-ok { background: var(--mastered-bg); border-color: transparent; }
.feedback.is-bad { background: var(--repeat-bg); border-color: transparent; }

.plain { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 8px; }

.plain button {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  padding: 8px 0;
  border: 0;
  background: transparent;
  text-align: left;
  min-height: 44px;
}

.person ul li, .bar-row { justify-content: space-between; }

.person li {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 8px;
  padding: 4px 0;
}

.bar-row span:first-child { width: 118px; flex: 0 0 auto; font-size: 14px; }

.topic-card { display: flex; flex-direction: column; align-items: stretch; gap: 8px; text-align: left; }

.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 16px; background: white; }

.map-table { display: none; }

table { width: 100%; border-collapse: collapse; font-size: 14px; }

th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: middle; }

th { color: var(--muted); font-weight: 700; font-size: 13px; }

td:first-child, th:first-child { position: sticky; left: 0; background: white; }

.profile-card { display: flex; flex-direction: column; align-items: flex-start; gap: 8px; }

.empty { display: flex; flex-direction: column; align-items: flex-start; gap: 8px; }

.statusline { margin: 0; font-weight: 700; color: var(--accent-ink); }

.tabbar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  background: rgba(255, 255, 255, 0.96);
  border-top: 1px solid var(--line);
  padding-bottom: env(safe-area-inset-bottom);
  backdrop-filter: blur(10px);
}

.role-teacher .tabbar { grid-template-columns: repeat(5, 1fr); }

.tab {
  min-height: 56px;
  border: 0;
  background: transparent;
  color: var(--muted);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  font-size: 10px;
  font-weight: 700;
  padding: 6px 2px;
}

.tab span { line-height: 1.15; text-align: center; }

.tab.is-active { color: var(--accent); }

.sidenav {
  display: none;
  flex-direction: column;
  gap: 4px;
  padding: 22px 14px;
  background: white;
  border-right: 1px solid var(--line);
}

.side-brand { padding: 4px 8px 8px; }

.side-note { margin: 0 8px 10px; }

.side-link {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 0 10px;
  box-shadow: none;
  border-color: transparent;
  background: transparent;
  font-weight: 700;
  color: var(--muted);
}

.side-link.is-active { background: var(--accent-soft); color: var(--accent-ink); }

.gate {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 12px;
  padding: 32px 20px calc(32px + env(safe-area-inset-bottom));
  width: min(460px, 100%);
  margin: 0 auto;
}

.demo-banner {
  position: sticky;
  top: 0;
  z-index: 6;
  background: var(--lime);
  color: var(--lime-ink);
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 700;
}

.skeleton { display: flex; flex-direction: column; gap: 10px; }

.skeleton span {
  display: block;
  height: 14px;
  border-radius: 8px;
  background: #eceef6;
}

.toast {
  position: fixed;
  left: 16px;
  right: 16px;
  bottom: calc(76px + env(safe-area-inset-bottom));
  z-index: 30;
  background: var(--text);
  color: white;
  border-radius: 14px;
  padding: 12px 14px;
  width: min(560px, calc(100% - 32px));
  margin: 0 auto;
}

.sheet {
  border: 0;
  border-radius: 22px;
  padding: 20px;
  width: min(420px, calc(100% - 32px));
  box-shadow: 0 20px 50px rgba(25, 27, 42, 0.18);
}

.sheet::backdrop { background: rgba(25, 27, 42, 0.4); }

.sheet h2 { margin-bottom: 8px; }

.sheet p { color: var(--muted); margin-bottom: 16px; }

.noscript { padding: 24px; }

@media (max-width: 360px) {
  .pair { grid-template-columns: 1fr; }
}

@media (min-width: 720px) {
  .page { padding-left: 24px; padding-right: 24px; }
  .topic-grid, .people, .stat-grid { grid-template-columns: 1fr 1fr; }
  .stat-grid { align-items: stretch; }
}

@media (min-width: 840px) {
  .role-student .tabbar {
    left: 50%;
    right: auto;
    width: min(640px, calc(100% - 32px));
    transform: translateX(-50%);
    bottom: 16px;
    border: 1px solid var(--line);
    border-radius: 22px;
    overflow: hidden;
    box-shadow: var(--shadow);
  }
}

@media (min-width: 960px) {
  .role-teacher .tabbar { display: none; }
  .role-teacher .frame {
    display: grid;
    grid-template-columns: 232px minmax(0, 1fr);
    min-height: 100dvh;
  }
  .role-teacher .sidenav { display: flex; position: sticky; top: 0; height: 100dvh; }
  .role-teacher .page { padding-bottom: 40px; }
  .role-teacher .mobile-brand { display: none; }
  .people { display: none; }
  .map-table { display: block; }
}

@media (hover: hover) {
  .btn-primary:hover { background: var(--accent-ink); }
  .btn-ghost:hover, .chip:hover, .choice:hover { background: #f6f7fb; }
  .tab:hover { color: var(--text); }
}

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