* { box-sizing: border-box; }
html, body { overflow-x: clip; }
body { margin: 0; background: var(--color-page); color: var(--color-ink); font: 15px/1.55 var(--font-body); }
button, input, select, textarea { font: inherit; }
button { color: inherit; cursor: pointer; }
button:disabled { cursor: default; opacity: .42; }
button, input, select, textarea, a { -webkit-tap-highlight-color: var(--color-clear); }
:focus-visible { outline: 2px solid var(--color-focus); outline-offset: 3px; }
button:not(:disabled):active { transform: translateY(1px); }
h1[tabindex="-1"]:focus { outline: none; }
button, h1, h2, h3, p, ol { margin: 0; }
h1, h2, h3 { line-height: 1.25; overflow-wrap: anywhere; min-width: 0; }
button { white-space: nowrap; }
[hidden] { display: none !important; }
svg { display: block; flex: none; }
.shell { width: min(1120px, calc(100% - 64px)); margin-inline: auto; }
.topbar { background: var(--color-panel); border-bottom: 1px solid var(--color-rule); }
.topbar .shell { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: var(--space-sm); }
.brand { display: inline-flex; align-items: center; gap: 10px; font-size: 20px; letter-spacing: -.045em; font-weight: 750; white-space: nowrap; }
.brand-mark { width: 36px; height: 36px; display: grid; place-items: center; background: var(--color-accent); color: var(--color-panel); border-radius: 10px; }
.roles { display: flex; align-items: center; padding: 4px; gap: 3px; background: var(--color-page); border: 1px solid var(--color-rule); border-radius: 10px; }
.role { border: 1px solid var(--color-clear); background: var(--color-clear); padding: 6px 13px; min-height: 36px; border-radius: 7px; display: inline-flex; gap: 6px; align-items: center; font-size: 13px; color: var(--color-muted); }
.role[aria-pressed=true] { color: var(--color-accent); background: var(--color-panel); border-color: var(--color-rule); box-shadow: 0 1px 2px var(--color-shadow); font-weight: 700; }
.role:hover, .text-button:hover { color: var(--color-accent); }
main.shell { padding-block: var(--space-lg) 48px; }
.hero { position: relative; isolation: isolate; display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr); min-height: 194px; overflow: clip; border-radius: var(--radius-lg); background: linear-gradient(110deg, var(--color-hero) 18%, var(--color-hero-edge)); color: var(--color-hero-ink); }
.hero-copy { padding: var(--space-lg) var(--space-2xl); z-index: 1; align-self: center; }
.hero h1 { font: 750 clamp(42px, 5.4vw, 70px)/1.16 var(--font-display); letter-spacing: -.064em; margin-bottom: var(--space-xs); }
.hero h1 span { color: var(--color-accent); }
.hero p { color: var(--color-hero-muted); font-size: 16px; }
.class-chip { position: relative; display: inline-flex; color: var(--color-muted); background: var(--color-panel); border: 1px solid var(--color-rule); border-radius: var(--radius-sm); }
.class-chip select { appearance: none; min-height: 42px; background: var(--color-clear); color: inherit; border: 0; border-radius: inherit; padding: 5px 29px 5px 31px; font-size: 13px; cursor: pointer; }
.class-chip svg { position: absolute; top: 50%; transform: translateY(-50%); pointer-events: none; }
.class-chip svg:first-child { left: 10px; }
.class-chip svg:last-child { right: 10px; }
.class-chip:focus-within { border-color: var(--color-focus); }
.hero-art { position: absolute; inset: 0 0 0 47%; display: grid; place-items: center; pointer-events: none; overflow: clip; }
.ring { position: absolute; width: var(--diameter); aspect-ratio: 1; border: 1px solid var(--color-hero-rule); border-radius: 50%; left: 56%; top: 50%; transform: translate(-50%, -50%); }
.wave { display: flex; position: relative; align-items: center; justify-content: center; gap: clamp(3px, .7vw, 10px); height: 132px; width: 100%; }
.hero-art .wave { padding-left: 11%; transform: scaleY(.78); }
.wave::before { content: ""; position: absolute; height: 1px; background: var(--color-hero-rule); width: 100%; left: 0; top: 50%; }
.wave i { z-index: 1; display: block; width: clamp(2px, .34vw, 5px); height: var(--bar); border-radius: var(--radius-pill); background: var(--color-wave-soft); }
.wave i:nth-child(3n), .wave i:nth-child(4n) { background: var(--color-wave); }
.workbench { display: grid; grid-template-columns: minmax(0, 1fr) minmax(320px, .49fr); gap: var(--space-lg); margin-top: var(--space-xl); align-items: start; }
.section-title { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: var(--space-xs); margin-bottom: var(--space-sm); }
.subject-filter { display: flex; gap: var(--space-xs); margin-bottom: var(--space-md); }
.subject-filter__button { min-height: 44px; padding: 6px 17px; color: var(--color-muted); background: var(--color-panel); border: 1px solid var(--color-rule); border-radius: var(--radius-pill); font-size: 14px; font-weight: 650; }
.subject-filter__button:hover, .subject-filter__button[aria-pressed="true"] { background: var(--color-tint); color: var(--color-accent-dark); border-color: var(--color-line-picked); }
.section-title h2, .queue h2 { font-size: 23px; letter-spacing: -.055em; }
.task-list { display: grid; gap: var(--space-sm); }
.task, .queue, .practice-card, .result-card, .form-panel, .teacher-list { background: var(--color-panel); border: 1px solid var(--color-rule); border-radius: var(--radius-md); box-shadow: 0 2px 6px var(--color-shadow); min-width: 0; }
.task.chosen { border-color: var(--color-line-picked); }
.task-head { --task-icon-size: 44px; display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 0 var(--space-sm); padding: var(--space-sm) var(--space-md); }
.task-title { grid-column: 1; min-width: 0; }
.task-toggle { display: flex; align-items: center; gap: var(--space-sm); padding: 0; min-height: 44px; width: 100%; text-align: left; background: var(--color-clear); border: 0; border-radius: var(--radius-sm); font-size: 17px; }
.task-toggle:hover { color: var(--color-accent); }
.task-title__text { overflow-wrap: anywhere; white-space: normal; min-width: 0; font-weight: 750; }
.task-toggle > svg { margin-inline-start: auto; color: var(--color-muted); }
.task-toggle .subject-icon { width: var(--task-icon-size); height: var(--task-icon-size); }
.task-meta { grid-column: 1 / -1; padding-inline-start: calc(var(--task-icon-size) + var(--space-sm)); }
.subject-icon { background: var(--color-tint); color: var(--color-accent); width: 46px; height: 46px; border-radius: 10px; display: grid; place-items: center; flex: none; font-weight: 750; font-size: 21px; }
.subject-icon.zh { font-family: var(--font-display); }
.subject-icon.en { background: var(--color-blue-tint); color: var(--color-blue); letter-spacing: -.06em; }
.task-meta, .queue-meta { flex: 1; min-width: 0; }
.task-meta p, .queue-meta p { color: var(--color-muted); font-size: 12px; margin-top: 4px; }
.task-meta p { overflow-wrap: anywhere; }
.curriculum { display: flex; align-items: baseline; flex-wrap: wrap; gap: 4px 8px; margin-top: 8px; font-size: 12px; min-width: 0; }
.curriculum-location { border-radius: 5px; background: var(--color-tint); color: var(--color-accent); padding: 2px 6px; font-weight: 700; }
.curriculum-topic { color: var(--color-muted); overflow-wrap: anywhere; min-width: 0; }
.progress-text span:first-child { overflow-wrap: anywhere; min-width: 0; }
.progress-text span:last-child { white-space: nowrap; }
.practice-status .curriculum { margin-top: 4px; }
.icon-button, .text-button { background: var(--color-clear); border: 0; border-radius: var(--radius-sm); display: inline-flex; align-items: center; justify-content: center; gap: 6px; color: var(--color-muted); }
.icon-button { width: 36px; height: 36px; flex: none; }
.icon-button:hover:not(:disabled), .text-button:hover:not(:disabled) { background: var(--color-tint); }
.text-button { padding: 7px 9px; min-height: 36px; font-size: 13px; }
.task-toggle[aria-expanded=true] svg { transform: rotate(180deg); }
.task-toggle svg { transition: transform 170ms var(--ease-out); }
input[type=checkbox] { appearance: none; display: inline-grid; place-items: center; width: 19px; height: 19px; border: 1px solid var(--color-control); border-radius: 5px; background: var(--color-panel); margin: 0; cursor: pointer; color: var(--color-panel); flex: none; }
input[type=checkbox]:checked, input[type=checkbox]:indeterminate { background: var(--color-accent); border-color: var(--color-accent); }
input[type=checkbox]:checked::after { content: ""; width: 8px; height: 4px; border-left: 2px solid currentColor; border-bottom: 2px solid currentColor; transform: translateY(-1px) rotate(-45deg); }
input[type=checkbox]:indeterminate::after { content: ""; width: 9px; border-top: 2px solid currentColor; }
.check-hit { grid-area: 1 / 2; min-height: 44px; display: flex; align-items: center; gap: 6px; padding-inline: 8px; color: var(--color-muted); font-size: 12px; cursor: pointer; border-radius: var(--radius-sm); white-space: nowrap; }
.check-hit:hover { background: var(--color-tint); color: var(--color-accent-dark); }
.task-body { border-top: 1px solid var(--color-rule); padding: var(--space-sm) 18px var(--space-md); }
.unit-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-xs); }
.unit { display: flex; align-items: center; padding: 7px 10px; gap: 9px; min-height: 44px; background: var(--color-page); border: 1px solid var(--color-rule); border-radius: var(--radius-sm); cursor: pointer; }
.unit:has(:checked) { background: var(--color-picked); border-color: var(--color-rule); }
.unit:hover { border-color: var(--color-line-picked); }
.unit span { min-width: 0; overflow-wrap: anywhere; white-space: pre-wrap; }
.unit.zh span { font-family: var(--font-display); font-weight: 650; font-size: 17px; }
.unit input { width: 16px; height: 16px; }
.queue { padding: var(--space-lg); position: sticky; top: var(--space-md); scroll-margin-bottom: 100px; }
.queue h2 { display: flex; align-items: center; gap: 8px; font-size: 21px; }
.queue-heading { display: flex; gap: var(--space-xs); align-items: center; justify-content: space-between; }
.counter { padding: 3px 9px; background: var(--color-tint); border-radius: var(--radius-pill); color: var(--color-accent); font-size: 12px; font-weight: 700; white-space: nowrap; font-variant-numeric: tabular-nums; }
.queue-list { list-style: none; display: grid; padding: 0; margin: 15px 0 18px; }
.queue-row { display: flex; align-items: center; gap: 10px; min-height: 62px; border-bottom: 1px solid var(--color-rule); padding-block: 8px; }
.queue-row:first-child { border-top: 1px solid var(--color-rule); }
.queue-order { font-size: 12px; color: var(--color-muted); min-width: 16px; text-align: center; font-variant-numeric: tabular-nums; }
.queue-row .subject-icon, .result-row .subject-icon { width: 33px; height: 33px; font-size: 15px; border-radius: 7px; }
.queue-meta strong { display: block; font-size: 14px; overflow-wrap: anywhere; }
.queue-meta p { margin-top: 1px; }
.reorder { display: flex; gap: 2px; }
.reorder .icon-button { width: 36px; height: 44px; }
.btn { padding: 10px 15px; min-height: 44px; border-radius: var(--radius-sm); border: 1px solid var(--color-rule); background: var(--color-panel); font-weight: 700; display: inline-flex; align-items: center; justify-content: center; gap: 8px; }
.btn:hover:not(:disabled) { border-color: var(--color-line-picked); background: var(--color-tint); }
.btn.primary { background: var(--color-accent); color: var(--color-panel); border-color: var(--color-accent); }
.btn.primary:hover:not(:disabled) { background: var(--color-accent-dark); }
.start { width: 100%; justify-content: space-between; padding-inline: 15px; }
.start .button-copy { display: flex; align-items: center; gap: 8px; }
.practice-dock { display: none; }
.resume { display: flex; align-items: center; justify-content: space-between; gap: 10px; background: var(--color-tint); padding: var(--space-sm) var(--space-md); margin-bottom: var(--space-md); border-radius: var(--radius-sm); color: var(--color-accent); }
.resume p { font-size: 13px; }
.empty { padding: var(--space-md) 0; color: var(--color-muted); }
.task-list > .empty { padding: var(--space-lg); border: 1px dashed var(--color-line-picked); border-radius: var(--radius-md); }
footer.shell { display: flex; align-items: center; justify-content: space-between; gap: var(--space-sm); border-top: 1px solid var(--color-rule); padding-block: 14px 22px; font-size: 12px; color: var(--color-muted); }
.view-top { display: flex; justify-content: space-between; align-items: center; gap: var(--space-sm); margin-bottom: var(--space-md); }
.view-top .text-button { padding-left: 0; }
.practice, .result { width: min(760px, 100%); margin-inline: auto; }
.practice-status { display: grid; gap: 8px; margin-bottom: var(--space-md); }
.progress-text { display: flex; justify-content: space-between; gap: 8px; color: var(--color-muted); font-size: 13px; font-variant-numeric: tabular-nums; }
.progress-track { background: var(--color-rule); height: 7px; border-radius: var(--radius-pill); overflow: clip; }
.progress-track i { display: block; height: 100%; background: var(--color-accent); border-radius: inherit; }
.practice-card { overflow: clip; }
.reading-stage { position: relative; display: grid; justify-items: center; align-content: center; gap: 18px; min-height: 320px; padding: var(--space-xl); background: radial-gradient(ellipse at 50% 100%, var(--color-hero), var(--color-hero-edge) 82%); color: var(--color-hero-ink); }
.stage-badge { font-size: 13px; color: var(--color-hero-muted); background: var(--color-panel); border: 1px solid var(--color-hero-rule); border-radius: var(--radius-pill); padding: 4px 12px; display: flex; align-items: center; gap: 7px; }
.reading-text { font: 750 clamp(32px, 6vw, 66px)/1.36 var(--font-display); white-space: pre-wrap; text-align: center; letter-spacing: -.035em; overflow-wrap: anywhere; max-width: 100%; }
.reading-text.en { font-family: var(--font-body); }
.stage-wave { width: 100%; max-width: 220px; height: 62px; gap: 4px; margin-block: 0; }
.stage-wave i { flex: none; width: 3px; height: min(var(--bar), 30px); transform: scaleY(.10); transform-origin: center; }
.is-playing .stage-wave i { animation: pulse 720ms var(--ease-out) alternate infinite; animation-delay: var(--delay); }
@keyframes pulse { to { transform: scaleY(1); } }
.practice-bottom { display: grid; gap: var(--space-md); padding: var(--space-lg); }
.practice-bottom p { color: var(--color-muted); min-height: 24px; }
.practice-bottom .practice-countdown { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; margin-left: auto; font-size: 13px; }
.practice-countdown__time { min-width: 48px; padding: 4px 8px; border-radius: var(--radius-pill); background: var(--color-tint); color: var(--color-accent-dark); font-weight: 700; text-align: center; font-variant-numeric: tabular-nums; }
.practice-bottom p.error, .error { color: var(--color-danger); }
.practice-actions { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: var(--space-xs); }
.practice-upcoming { display: flex; align-items: baseline; gap: var(--space-xs); border-top: 1px solid var(--color-rule); padding-top: var(--space-sm); font-size: 13px; color: var(--color-muted); }
.practice-upcoming span { flex: none; }
.practice-upcoming strong { color: var(--color-ink); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.result-card { padding: clamp(20px, 5vw, 40px); }
.result-card h1 { margin-top: 15px; font: 750 44px/1.2 var(--font-display); }
.result-card > p { color: var(--color-muted); margin: 10px 0 24px; }
.result-mark { display: grid; place-items: center; width: 48px; height: 48px; background: var(--color-tint); color: var(--color-accent); border-radius: 14px; }
.result-row { display: flex; align-items: center; gap: 12px; border-top: 1px solid var(--color-rule); padding-block: 13px; }
.result-row strong:last-child { margin-left: auto; font-variant-numeric: tabular-nums; }
.result-card > .btn { margin-top: 18px; }
.teacher-heading { margin-bottom: var(--space-lg); }
.teacher-heading h1 { font: 750 clamp(32px, 5vw, 48px)/1.2 var(--font-display); }
.teacher-heading p { margin-top: 8px; color: var(--color-muted); }
.teacher-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(300px, .72fr); gap: var(--space-lg); align-items: start; }
.form-panel, .teacher-list { padding: var(--space-lg); }
.form-panel h2, .teacher-list h2 { font-size: 21px; margin-bottom: var(--space-md); }
.form-stack { display: grid; gap: 15px; }
.fields { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-sm); }
.field { display: grid; gap: 5px; color: var(--color-ink); font-size: 13px; font-weight: 700; min-width: 0; }
.field input, .field select, .field textarea { border-radius: var(--radius-sm); border: 1px solid var(--color-rule); min-width: 0; width: 100%; background: var(--color-page); padding: 9px 10px; color: var(--color-ink); font-weight: 500; }
.field textarea { min-height: 122px; resize: vertical; }
.field small { color: var(--color-muted); font-weight: 400; }
.form-actions { display: flex; gap: var(--space-xs); flex-wrap: wrap; }
.form-message { font-size: 13px; min-height: 20px; color: var(--color-muted); }
.form-message.error { color: var(--color-danger); }
.unit-preview { display: grid; gap: 2px; padding: 0; list-style: none; max-height: 230px; overflow: auto; }
.preview-row { min-width: 0; display: grid; grid-template-columns: minmax(0, 1fr) auto auto auto auto; align-items: center; gap: 4px; border-bottom: 1px solid var(--color-rule); padding: 3px 0; }
.preview-row .icon-button { width: 32px; }
.preview-row span { overflow-wrap: anywhere; white-space: pre-wrap; font-size: 13px; }
.teacher-task { display: flex; align-items: center; gap: 10px; padding: 10px 0; border-top: 1px solid var(--color-rule); }
.teacher-task strong { display: block; overflow-wrap: anywhere; }
.teacher-task .subject-icon { width: 35px; height: 35px; font-size: 16px; }
.danger:hover { color: var(--color-danger); }
@media (max-width: 820px) {
  .shell { width: calc(100% - 40px); }
  .workbench { grid-template-columns: minmax(0, 1fr) minmax(280px, .72fr); gap: var(--space-md); }
  .queue, .form-panel, .teacher-list { padding: var(--space-md); }
  .hero-copy { padding-inline: var(--space-lg); }
  .task-head { column-gap: 6px; padding-inline: 13px; }
  .task-body { padding-inline: 13px; }
}
@media (max-width: 680px) {
  .workbench, .teacher-grid { grid-template-columns: minmax(0, 1fr); }
  .queue { position: static; }
  .queue:not(.queue--resumable) .start { display: none; }
  body:has(.practice-dock) { padding-bottom: calc(78px + env(safe-area-inset-bottom)); }
  .practice-dock { display: block; position: fixed; z-index: 2; inset: auto 0 0; padding: 10px max(14px, env(safe-area-inset-right)) calc(10px + env(safe-area-inset-bottom)) max(14px, env(safe-area-inset-left)); background: var(--color-panel); border-top: 1px solid var(--color-rule); box-shadow: 0 -4px 22px var(--color-shadow); }
  .practice-dock__inner { width: min(460px, 100%); margin-inline: auto; display: grid; grid-template-columns: auto minmax(0, 1fr); gap: var(--space-sm); }
  .practice-dock__queue { min-height: 44px; color: var(--color-accent-dark); font-weight: 700; }
  .hero { grid-template-columns: minmax(0, 1fr); min-height: 152px; }
  .hero-art { inset-inline-start: 43%; opacity: .44; }
  .hero p { max-width: 200px; font-size: 14px; }
  .hero-copy { padding-block: var(--space-lg); }
  main.shell { padding-block: var(--space-lg) var(--space-xl); }
  .workbench { margin-top: var(--space-lg); }
  .reading-stage { min-height: 275px; }
  footer.shell { align-items: flex-start; }
}
@media (max-width: 390px) {
  .shell { width: calc(100% - 28px); }
  .topbar .shell { min-height: 60px; }
  .brand { font-size: 17px; gap: 6px; }
  .brand-mark { width: 29px; height: 29px; }
  .role { padding-inline: 8px; }
  .role svg { display: none; }
  .hero-copy { padding-inline: var(--space-md); }
  .hero-art { inset-inline-start: 50%; }
  .task-head { --task-icon-size: 34px; }
  .task-toggle { font-size: 16px; }
  .unit { gap: 6px; padding-inline: 7px; }
  .unit.zh span { font-size: 15px; }
  .practice-bottom { padding: var(--space-md); }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

.curriculum-location { border: 1px solid var(--color-line-picked); }
.stage-badge { transition: background-color 160ms var(--ease-out), color 160ms var(--ease-out); }
.reading-stage[data-phase="reading"] .stage-badge { color: var(--color-accent-dark); background: var(--color-hero-chip); }
.stage-wave i { transition: transform 60ms linear; }
.teacher-login { width: min(440px, 100%); padding: clamp(20px, 4vw, 40px); margin: var(--space-xl) auto; }
.teacher-login h1 { font: 750 36px/1.2 var(--font-display); }
.teacher-login > p { color: var(--color-muted); margin-block: 10px var(--space-lg); }
.teacher-heading--with-action, .materials-error { display: flex; align-items: flex-start; justify-content: space-between; gap: var(--space-sm); }
.materials-error { align-items: center; }