:root {
  color-scheme: light;
  --bg: #f7f3ea;
  --panel: #fffdf8;
  --ink: #24160f;
  --muted: #75675c;
  --line: #e7dccb;
  --red: #d73b2f;
  --red-dark: #a52820;
  --gold: #f0b429;
  --green: #237b4b;
  --shadow: 0 14px 40px rgba(55, 36, 19, 0.10);
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
body { margin: 0; background: radial-gradient(circle at top left, #fff6dd, var(--bg) 38rem); color: var(--ink); overflow-x: hidden; }
button, input { font: inherit; }
button { cursor: pointer; }
button:disabled { opacity: .55; cursor: not-allowed; }

.app-shell { max-width: 920px; min-height: 100vh; margin: 0 auto; padding: 0 16px 40px; }
.app-header { position: sticky; top: 0; z-index: 5; display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 12px 0; background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: blur(14px); }
.brand { display: flex; align-items: center; gap: 8px; border: 0; background: transparent; color: var(--ink); font-weight: 800; text-align: left; }
.brand-mark { display: grid; place-items: center; width: 38px; height: 38px; padding: 0; border: 0; border-radius: 12px; background: transparent; color: white; font-size: 1.25rem; box-shadow: var(--shadow); overflow: hidden; }
.brand-mark img { display: block; width: 100%; height: 100%; }
.brand-mark.mini { flex: 0 0 auto; width: 38px; height: 38px; }
.screen { margin-top: 18px; }
.hero { display: grid; grid-template-columns: 1fr; gap: 18px; padding: 26px; border: 1px solid var(--line); border-radius: 28px; background: linear-gradient(135deg, #fffdf8, #fff3dd); box-shadow: var(--shadow); }
.hero h1 { margin: 0 0 8px; font-size: clamp(2rem, 8vw, 4.3rem); line-height: .95; letter-spacing: -.06em; word-break: normal; overflow-wrap: normal; }
.hero h1 .ui-text { white-space: normal; word-break: keep-all; overflow-wrap: normal; }
.hero p, .pack-card p, .lesson-row p, .panel p { color: var(--muted); }
.hero-actions, .button-row { display: flex; gap: 10px; flex-wrap: wrap; }

.button { display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 11px 16px; border-radius: 15px; border: 1px solid transparent; background: var(--red); color: white; font-weight: 750; box-shadow: 0 8px 20px rgba(215, 59, 47, .18); }
.button.secondary { background: var(--panel); color: var(--ink); border-color: var(--line); box-shadow: none; }
.button.ghost { background: transparent; color: var(--muted); border-color: var(--line); box-shadow: none; }
.button.danger { background: var(--red-dark); }
.link-button { border: 0; background: transparent; color: var(--red-dark); text-decoration: underline; padding: 12px 0; }

.stats-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-top: 14px; }
.stat-card, .panel { border: 1px solid var(--line); border-radius: 20px; padding: 16px; background: var(--panel); }
button.stat-card { text-align: left; color: inherit; cursor: pointer; }
.stat-card.clickable:hover, .home-settings-link:hover { border-color: #d8b98d; transform: translateY(-1px); }
.home-settings-link { display: flex; align-items: center; justify-content: space-between; gap: 12px; cursor: pointer; transition: transform .15s ease, border-color .15s ease; }
.home-settings-link h2 { margin: 0 0 4px; }
.home-settings-link p { margin: 0; }
.ongoing-session { display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.ongoing-session h2 { margin: 0 0 4px; }
.ongoing-session p { margin: 0; color: var(--muted); }
.session-actions { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.stat-card strong { display: block; font-size: 1.8rem; }
.stat-card span { color: var(--muted); font-size: .92rem; }
.summary-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-top: 14px; }
.summary-card { border: 1px solid #ead8bd; border-radius: 18px; padding: 13px 14px; background: #fff8e8; box-shadow: inset 0 0 0 1px rgba(255,255,255,.55); }
.summary-card strong { display: block; font-size: 1.55rem; line-height: 1; }
.summary-card span { display: block; margin-top: 5px; color: var(--muted); font-size: .88rem; }

.pack-list, .lesson-list { display: grid; gap: 12px; }
.pack-card, .lesson-row { display: grid; gap: 12px; align-items: center; border: 1px solid var(--line); border-radius: 22px; padding: 16px; background: var(--panel); }
.pack-card { grid-template-columns: 1fr auto; cursor: pointer; transition: transform .15s ease, border-color .15s ease; }
.pack-card:hover { transform: translateY(-1px); border-color: #d8b98d; }
.pack-card h3, .lesson-row h3 { margin: 0 0 5px; }
.pack-card p, .lesson-row p { margin: 0; }
.lesson-row { grid-template-columns: auto 1fr auto; }
.lesson-row.done { background: #f7fff5; }
.lesson-date { margin-top: 4px; }
.lesson-row-actions { display: flex; align-items: center; justify-content: flex-end; gap: 10px; flex-wrap: wrap; }
.lesson-number { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 12px; background: #f7e5c3; font-weight: 800; }
.pill { display: inline-flex; align-items: center; border-radius: 999px; padding: 6px 10px; background: #f4e8d8; color: #6f4d23; font-weight: 750; }

.top-row { display: flex; justify-content: space-between; align-items: center; gap: 10px; }
.top-actions { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.focus-top-row { display: flex; align-items: center; gap: 10px; margin-top: 10px; }
.focus-spacer { flex: 1; }
.danger-link { color: var(--red-dark); }
.progress-bar { height: 10px; border-radius: 999px; background: #eadfce; overflow: hidden; margin: 12px 0 18px; }
.progress-bar span { display: block; height: 100%; background: linear-gradient(90deg, var(--red), var(--gold)); }
.exercise-card { display: grid; gap: 16px; border: 1px solid var(--line); border-radius: 28px; padding: 22px; background: var(--panel); box-shadow: var(--shadow); }
.exercise-card h2 { margin: 0; font-size: clamp(1.35rem, 5vw, 2rem); }
.eyebrow { color: var(--muted); text-transform: uppercase; letter-spacing: .08em; font-size: .78rem; font-weight: 800; }
.hanzi { font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif; word-break: keep-all; overflow-wrap: normal; white-space: nowrap; }
.hanzi.big { font-size: clamp(4rem, 22vw, 8rem); line-height: 1; font-weight: 900; }
.pinyin { color: var(--red-dark); font-size: 1.25rem; font-weight: 700; }
.choice-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.choice { min-height: 58px; padding: 12px; border-radius: 18px; border: 1px solid var(--line); background: #fffaf0; font-weight: 750; }
.answer-form { display: grid; grid-template-columns: 1fr auto; gap: 10px; }
.answer-form input { min-width: 0; border: 1px solid var(--line); border-radius: 16px; padding: 12px 14px; background: white; font-size: 1.1rem; }
.result { border-radius: 18px; padding: 14px; }
.result.correct { background: #eaf8ef; color: var(--green); }
.result.wrong { background: #fff0ee; color: var(--red-dark); }
.complete-card { text-align: center; }

.settings-screen label { display: block; margin: 10px 0; }
.notice { border-radius: 16px; padding: 12px; background: #eaf8ef; color: var(--green); }
.muted { color: var(--muted); }
.small { font-size: .9rem; }
.learned-list { display: grid; gap: 10px; margin-top: 16px; }
.learned-card { display: grid; grid-template-columns: 1fr auto; gap: 12px; align-items: center; border: 1px solid var(--line); border-radius: 20px; padding: 14px; background: var(--panel); }
.learned-main { display: grid; grid-template-columns: auto minmax(0, 1fr); align-items: center; gap: 14px; min-width: 0; }
.learned-copy { min-width: 0; overflow-wrap: anywhere; }
.learned-hanzi { display: grid; place-items: center; min-width: 68px; max-width: min(42vw, 180px); min-height: 64px; padding: 8px 12px; border-radius: 18px; background: #fff3dd; color: var(--red-dark); font-size: 1.85rem; font-weight: 900; line-height: 1.02; text-align: center; white-space: normal; word-break: normal; overflow-wrap: anywhere; }
.learned-hanzi.long { font-size: 1.62rem; }
.learned-hanzi.phrase { font-size: 1.42rem; max-width: min(42vw, 152px); }
.learned-meta { display: grid; justify-items: end; gap: 4px; text-align: right; }
.status-chip { display: inline-flex; border-radius: 999px; padding: 5px 9px; font-size: .82rem; font-weight: 800; background: #f4e8d8; color: #6f4d23; }
.status-chip.due { background: #fff0ee; color: var(--red-dark); }
.status-chip.strong { background: #eaf8ef; color: var(--green); }
.status-chip.learning { background: #fff7d6; color: #806000; }
.status-chip.weak { background: #f4e8d8; color: #6f4d23; }
.empty-state { text-align: center; }
.ui-text { white-space: nowrap; }

@media (max-width: 900px) {
  .app-shell { padding-inline: 12px; padding-bottom: 40px; }
  .app-shell.focus-mode { padding-bottom: 40px; }
  .app-header { position: static; align-items: center; justify-content: flex-start; padding: 12px 0 4px; background: transparent; backdrop-filter: none; }
  .brand span:last-child { display: none; }
  .stats-grid, .summary-grid { grid-template-columns: 1fr; }
  .lesson-row { grid-template-columns: auto 1fr; }
  .lesson-row .button { grid-column: 1 / -1; }
  .lesson-row-actions { grid-column: 1 / -1; align-items: stretch; flex-direction: column; }
  .home-settings-link { align-items: flex-start; flex-direction: column; }
  .choice-grid, .answer-form { grid-template-columns: 1fr; }
  .ongoing-session { align-items: stretch; flex-direction: column; }
  .session-actions { align-items: stretch; flex-direction: column; }
  .top-row { align-items: flex-start; }
  .top-actions { gap: 6px; }
  .learned-card { grid-template-columns: 1fr; }
  .learned-main { align-items: start; gap: 12px; }
  .learned-hanzi { max-width: 38vw; }
  .learned-meta { justify-items: start; text-align: left; }
  .hero h1 { font-size: clamp(1.8rem, 11vw, 3.1rem); letter-spacing: -.04em; }
  .hero { padding: 20px; border-radius: 22px; }
}