/* ==========================================================================
   作业系统 — Material 3 风格样式
   设计令牌参考 Material Design 3 (baseline) 的紫色系配色。
   ========================================================================== */

:root {
  --md-primary: #6750a4;
  --md-on-primary: #ffffff;
  --md-primary-container: #eaddff;
  --md-on-primary-container: #21005d;
  --md-secondary: #625b71;
  --md-secondary-container: #e8def8;
  --md-on-secondary-container: #1d192b;
  --md-tertiary: #7d5260;
  --md-tertiary-container: #ffd8e4;
  --md-on-tertiary-container: #31111d;
  --md-error: #b3261e;
  --md-error-container: #f9dedc;
  --md-on-error-container: #410e0b;
  --md-surface: #fef7ff;
  --md-surface-dim: #ded8e1;
  --md-surface-container-lowest: #ffffff;
  --md-surface-container-low: #f7f2fa;
  --md-surface-container: #f3edf7;
  --md-surface-container-high: #ece6f0;
  --md-surface-container-highest: #e6e0e9;
  --md-on-surface: #1d1b20;
  --md-on-surface-variant: #49454f;
  --md-outline: #79747e;
  --md-outline-variant: #cac4d0;
  --md-inverse-surface: #322f35;
  --md-inverse-on-surface: #f5eff7;
  --md-success: #2e6b30;
  --md-success-container: #c8f0c6;
  --md-on-success-container: #05210a;
  --md-warning: #7a5900;
  --md-warning-container: #ffdf9e;
  --md-scrim: rgba(0, 0, 0, 0.32);

  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 28px;
  --radius-full: 999px;

  --elev-1: 0 1px 2px rgba(0, 0, 0, 0.30), 0 1px 3px 1px rgba(0, 0, 0, 0.15);
  --elev-2: 0 1px 2px rgba(0, 0, 0, 0.30), 0 2px 6px 2px rgba(0, 0, 0, 0.15);
  --elev-3: 0 4px 8px 3px rgba(0, 0, 0, 0.15), 0 1px 3px rgba(0, 0, 0, 0.30);

  --font: "Roboto", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", "Cascadia Code", "Fira Code", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --topbar-h: 64px;
  --content-max: 1080px;
}

[data-theme="dark"] {
  --md-primary: #d0bcff;
  --md-on-primary: #381e72;
  --md-primary-container: #4f378b;
  --md-on-primary-container: #eaddff;
  --md-secondary: #ccc2dc;
  --md-secondary-container: #4a4458;
  --md-on-secondary-container: #e8def8;
  --md-tertiary: #efb8c8;
  --md-tertiary-container: #633b48;
  --md-on-tertiary-container: #ffd8e4;
  --md-error: #f2b8b5;
  --md-error-container: #8c1d18;
  --md-on-error-container: #f9dedc;
  --md-surface: #141218;
  --md-surface-dim: #141218;
  --md-surface-container-lowest: #0f0d13;
  --md-surface-container-low: #1d1b20;
  --md-surface-container: #211f26;
  --md-surface-container-high: #2b2930;
  --md-surface-container-highest: #36343b;
  --md-on-surface: #e6e0e9;
  --md-on-surface-variant: #cac4d0;
  --md-outline: #938f99;
  --md-outline-variant: #49454f;
  --md-inverse-surface: #e6e0e9;
  --md-inverse-on-surface: #322f35;
  --md-success: #8fd694;
  --md-success-container: #1f4a22;
  --md-on-success-container: #c8f0c6;
  --md-warning: #f0c14b;
  --md-warning-container: #4d3a00;
  --md-scrim: rgba(0, 0, 0, 0.55);
}

@media (prefers-color-scheme: dark) {
  html[data-theme="auto"] {
    --md-primary: #d0bcff;
    --md-on-primary: #381e72;
    --md-primary-container: #4f378b;
    --md-on-primary-container: #eaddff;
    --md-secondary: #ccc2dc;
    --md-secondary-container: #4a4458;
    --md-on-secondary-container: #e8def8;
    --md-tertiary: #efb8c8;
    --md-tertiary-container: #633b48;
    --md-on-tertiary-container: #ffd8e4;
    --md-error: #f2b8b5;
    --md-error-container: #8c1d18;
    --md-on-error-container: #f9dedc;
    --md-surface: #141218;
    --md-surface-dim: #141218;
    --md-surface-container-lowest: #0f0d13;
    --md-surface-container-low: #1d1b20;
    --md-surface-container: #211f26;
    --md-surface-container-high: #2b2930;
    --md-surface-container-highest: #36343b;
    --md-on-surface: #e6e0e9;
    --md-on-surface-variant: #cac4d0;
    --md-outline: #938f99;
    --md-outline-variant: #49454f;
    --md-inverse-surface: #e6e0e9;
    --md-inverse-on-surface: #322f35;
    --md-success: #8fd694;
    --md-success-container: #1f4a22;
    --md-on-success-container: #c8f0c6;
    --md-warning: #f0c14b;
    --md-warning-container: #4d3a00;
    --md-scrim: rgba(0, 0, 0, 0.55);
  }
}

*, *::before, *::after { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  background: var(--md-surface);
  color: var(--md-on-surface);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-wrap: break-word;
}

a { color: var(--md-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- 顶部应用栏 ---------- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 8px;
  height: var(--topbar-h);
  padding: 0 12px 0 8px;
  background: var(--md-surface-container);
  border-bottom: 1px solid var(--md-outline-variant);
  backdrop-filter: blur(8px);
}

.topbar__brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0 8px;
  font-size: 18px;
  font-weight: 500;
  letter-spacing: 0.15px;
  color: var(--md-on-surface);
}
.topbar__brand:hover { text-decoration: none; }
.topbar__logo {
  width: 30px; height: 30px;
  display: grid; place-items: center;
  border-radius: var(--radius-sm);
  background: var(--md-primary);
  color: var(--md-on-primary);
  font-size: 17px;
  font-weight: 700;
  flex: none;
}

.topbar__nav { display: flex; gap: 4px; margin-left: 8px; flex-wrap: wrap; }

.nav-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 38px;
  padding: 0 16px;
  border-radius: var(--radius-full);
  color: var(--md-on-surface-variant);
  font-size: 14px;
  font-weight: 500;
  white-space: nowrap;
}
.nav-pill:hover { background: var(--md-surface-container-high); text-decoration: none; }
.nav-pill[aria-current="page"] {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

.topbar__spacer { flex: 1; }
.topbar__right { display: flex; align-items: center; gap: 4px; }

/* ---------- 按钮 ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 40px;
  padding: 0 20px;
  border: none;
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--md-primary);
  font-family: inherit;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.1px;
  cursor: pointer;
  white-space: nowrap;
  transition: background-color 120ms ease, box-shadow 120ms ease, opacity 120ms ease;
}
.btn:hover { background: color-mix(in srgb, var(--md-primary) 8%, transparent); }
.btn:active { background: color-mix(in srgb, var(--md-primary) 14%, transparent); }
.btn:focus-visible { outline: 3px solid color-mix(in srgb, var(--md-primary) 45%, transparent); outline-offset: 2px; }
.btn[disabled] { opacity: 0.38; pointer-events: none; }

.btn--filled { background: var(--md-primary); color: var(--md-on-primary); }
.btn--filled:hover { background: color-mix(in srgb, var(--md-primary) 88%, var(--md-on-primary)); }
.btn--filled:active { background: color-mix(in srgb, var(--md-primary) 78%, var(--md-on-primary)); }

.btn--tonal { background: var(--md-secondary-container); color: var(--md-on-secondary-container); }
.btn--tonal:hover { background: color-mix(in srgb, var(--md-secondary-container) 88%, var(--md-on-secondary-container)); }

.btn--outlined { border: 1px solid var(--md-outline); color: var(--md-primary); }
.btn--outlined:hover { background: color-mix(in srgb, var(--md-primary) 8%, transparent); }

.btn--text { padding: 0 12px; }
.btn--danger { color: var(--md-error); }
.btn--danger:hover { background: color-mix(in srgb, var(--md-error) 10%, transparent); }
.btn--sm { min-height: 32px; padding: 0 14px; font-size: 13px; }
.btn--block { width: 100%; }

.icon-btn {
  display: inline-grid;
  place-items: center;
  width: 40px; height: 40px;
  border: none;
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--md-on-surface-variant);
  cursor: pointer;
  font-size: 18px;
  line-height: 1;
  transition: background-color 120ms ease;
}
.icon-btn:hover { background: var(--md-surface-container-high); }
.icon-btn:focus-visible { outline: 3px solid color-mix(in srgb, var(--md-primary) 45%, transparent); }

/* ---------- 卡片 ---------- */

.card {
  background: var(--md-surface-container-low);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.card--flat { background: var(--md-surface-container); border-color: transparent; }
.card--elev { border-color: transparent; box-shadow: var(--elev-1); }
.card__title { margin: 0 0 4px; font-size: 16px; font-weight: 500; letter-spacing: 0.15px; }
.card__sub { margin: 0; font-size: 13px; color: var(--md-on-surface-variant); }

/* ---------- 布局 ---------- */

.page {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 24px 16px 96px;
}
.page--narrow { max-width: 760px; }

.page-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}
.page-title {
  margin: 0;
  font-size: 26px;
  font-weight: 400;
  line-height: 1.3;
  letter-spacing: 0;
}
.page-desc { margin: 6px 0 0; color: var(--md-on-surface-variant); font-size: 14px; }
.page-actions { display: flex; gap: 8px; flex-wrap: wrap; }

.stack { display: flex; flex-direction: column; gap: 16px; }
.stack--sm { gap: 8px; }
.row { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.row--between { justify-content: space-between; }
.spacer { flex: 1; }

.grid { display: grid; gap: 16px; }
.grid--stats { grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); }

/* ---------- 表单控件 ---------- */

.field { display: flex; flex-direction: column; gap: 6px; }
.field__label { font-size: 12px; font-weight: 500; color: var(--md-on-surface-variant); letter-spacing: 0.4px; }
.field__hint { font-size: 12px; color: var(--md-on-surface-variant); }
.field__error { font-size: 12px; color: var(--md-error); }

.input, .textarea, .select {
  width: 100%;
  min-height: 48px;
  padding: 12px 16px;
  border: 1px solid var(--md-outline);
  border-radius: var(--radius-xs);
  background: var(--md-surface-container-lowest);
  color: var(--md-on-surface);
  font-family: inherit;
  font-size: 15px;
  line-height: 1.5;
  transition: border-color 120ms ease, box-shadow 120ms ease;
}
.input:focus, .textarea:focus, .select:focus {
  outline: none;
  border-color: var(--md-primary);
  box-shadow: inset 0 0 0 1px var(--md-primary);
}
.input::placeholder, .textarea::placeholder { color: var(--md-on-surface-variant); opacity: 0.7; }
.textarea { min-height: 96px; resize: vertical; }
.textarea--code, .input--code { font-family: var(--mono); font-size: 13.5px; tab-size: 2; }
.input--sm { min-height: 38px; padding: 6px 12px; font-size: 14px; }
.select { appearance: none; padding-right: 40px;
  background-image: linear-gradient(45deg, transparent 50%, currentColor 50%), linear-gradient(135deg, currentColor 50%, transparent 50%);
  background-position: calc(100% - 20px) 21px, calc(100% - 14px) 21px;
  background-size: 6px 6px, 6px 6px;
  background-repeat: no-repeat;
}

.checkbox, .radio {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  font-size: 14px;
  user-select: none;
}
.checkbox input, .radio input { width: 20px; height: 20px; accent-color: var(--md-primary); cursor: pointer; flex: none; }

.switch { display: inline-flex; align-items: center; gap: 10px; cursor: pointer; font-size: 14px; }
.switch input { appearance: none; width: 52px; height: 32px; border-radius: var(--radius-full);
  background: var(--md-surface-container-highest); border: 2px solid var(--md-outline);
  position: relative; cursor: pointer; transition: background-color 150ms ease, border-color 150ms ease; flex: none; }
.switch input::after { content: ""; position: absolute; top: 50%; left: 6px; width: 16px; height: 16px;
  border-radius: 50%; background: var(--md-outline); transform: translateY(-50%); transition: all 150ms ease; }
.switch input:checked { background: var(--md-primary); border-color: var(--md-primary); }
.switch input:checked::after { left: 26px; width: 24px; height: 24px; background: var(--md-on-primary); }

/* ---------- 芯片 ---------- */

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 32px;
  padding: 0 12px;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--md-on-surface-variant);
  font-size: 13px;
  white-space: nowrap;
}
.chip--filled { background: var(--md-secondary-container); border-color: transparent; color: var(--md-on-secondary-container); }
.chip--success { background: var(--md-success-container); border-color: transparent; color: var(--md-on-success-container); }
.chip--warn { background: var(--md-warning-container); border-color: transparent; color: var(--md-warning); }
.chip--error { background: var(--md-error-container); border-color: transparent; color: var(--md-on-error-container); }
.chip--primary { background: var(--md-primary-container); border-color: transparent; color: var(--md-on-primary-container); }
.chip--mono { font-family: var(--mono); font-size: 12px; }

/* ---------- 作业列表 ---------- */

.asg-list { display: grid; gap: 12px; }

.asg-card {
  display: flex;
  gap: 16px;
  padding: 18px 20px;
  background: var(--md-surface-container-low);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-md);
  transition: box-shadow 140ms ease, border-color 140ms ease, transform 140ms ease;
}
.asg-card:hover { border-color: var(--md-primary); box-shadow: var(--elev-1); }
.asg-card__main { flex: 1; min-width: 0; }
.asg-card__title { margin: 0 0 6px; font-size: 17px; font-weight: 500; }
.asg-card__title a { color: inherit; }
.asg-card__meta { display: flex; gap: 14px; flex-wrap: wrap; font-size: 13px; color: var(--md-on-surface-variant); }
.asg-card__side { display: flex; flex-direction: column; align-items: flex-end; gap: 8px; justify-content: center; flex: none; }

/* ---------- 题目 ---------- */

.q {
  background: var(--md-surface-container-low);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-md);
  padding: 20px;
}
.q--editing { border-color: var(--md-primary); }
.q__head { display: flex; align-items: flex-start; gap: 12px; margin-bottom: 12px; }
.q__index {
  flex: none;
  display: grid; place-items: center;
  min-width: 32px; height: 32px;
  padding: 0 8px;
  border-radius: var(--radius-full);
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  font-size: 14px;
  font-weight: 600;
}
.q__title { flex: 1; min-width: 0; }
.q__title h3 { margin: 0; font-size: 16px; font-weight: 500; line-height: 1.45; }
.q__points { flex: none; font-size: 13px; color: var(--md-on-surface-variant); white-space: nowrap; padding-top: 4px; }
.q__body { margin: 0 0 14px; }
.q__type-badge { font-size: 11px; letter-spacing: 0.5px; text-transform: uppercase; }

.opt-list { display: flex; flex-direction: column; gap: 8px; }
.opt {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 14px;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-sm);
  background: var(--md-surface-container-lowest);
  cursor: pointer;
  transition: border-color 120ms ease, background-color 120ms ease;
}
.opt:hover { border-color: var(--md-primary); }
.opt--picked { border-color: var(--md-primary); background: color-mix(in srgb, var(--md-primary) 8%, var(--md-surface-container-lowest)); }
.opt input { margin-top: 3px; width: 18px; height: 18px; accent-color: var(--md-primary); flex: none; cursor: pointer; }
.opt__key {
  flex: none; display: grid; place-items: center;
  width: 24px; height: 24px; border-radius: var(--radius-full);
  background: var(--md-surface-container-high); color: var(--md-on-surface-variant);
  font-size: 12px; font-weight: 600;
}
.opt__body { flex: 1; min-width: 0; }
.opt--correct { border-color: var(--md-success); background: color-mix(in srgb, var(--md-success) 10%, var(--md-surface-container-lowest)); }
.opt--wrong { border-color: var(--md-error); background: color-mix(in srgb, var(--md-error) 10%, var(--md-surface-container-lowest)); }

/* ---------- 代码题 ---------- */

.code-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}
@media (max-width: 900px) { .code-wrap { grid-template-columns: 1fr; } }

.code-view {
  border-radius: var(--radius-sm);
  border: 1px solid var(--md-outline-variant);
  overflow: hidden;
  background: var(--md-surface-container-lowest);
}
.code-view__head {
  display: flex; align-items: center; justify-content: space-between; gap: 8px;
  padding: 6px 12px;
  background: var(--md-surface-container-high);
  font-size: 12px;
  color: var(--md-on-surface-variant);
  font-family: var(--mono);
}
.code-table { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: 13px; line-height: 1.65; }
.code-table td { padding: 0 12px; vertical-align: top; }
.code-table td.ln {
  width: 1%;
  text-align: right;
  color: var(--md-on-surface-variant);
  opacity: 0.65;
  user-select: none;
  padding-right: 10px;
  white-space: nowrap;
  border-right: 1px solid var(--md-outline-variant);
}
.code-table td.src { white-space: pre-wrap; word-break: break-word; }
.code-table tr.region { background: color-mix(in srgb, var(--md-primary) 10%, transparent); }
.code-table tr.region-start td.ln { box-shadow: inset 3px 0 0 var(--md-primary); }
.code-table tr.region-other { background: color-mix(in srgb, var(--md-tertiary) 9%, transparent); }

.region-badge {
  display: inline-grid; place-items: center;
  min-width: 20px; height: 20px; padding: 0 6px;
  margin-left: 6px;
  border-radius: var(--radius-full);
  background: var(--md-primary);
  color: var(--md-on-primary);
  font-family: var(--font);
  font-size: 11px;
  font-weight: 700;
}

.region-answer { display: flex; flex-direction: column; gap: 14px; }
.region-answer__item { border: 1px solid var(--md-outline-variant); border-radius: var(--radius-sm); padding: 14px; background: var(--md-surface-container-lowest); }
.region-answer__head { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; font-weight: 500; font-size: 14px; }
.region-answer__head .chip { margin-left: auto; }

/* ---------- Markdown 渲染 ---------- */

.md { font-size: 15px; line-height: 1.7; }
.md > :first-child { margin-top: 0; }
.md > :last-child { margin-bottom: 0; }
.md h1, .md h2, .md h3, .md h4 { margin: 1.2em 0 0.5em; line-height: 1.35; font-weight: 600; }
.md h1 { font-size: 1.5em; }
.md h2 { font-size: 1.3em; }
.md h3 { font-size: 1.12em; }
.md p { margin: 0.6em 0; }
.md ul, .md ol { margin: 0.6em 0; padding-left: 1.6em; }
.md li { margin: 0.25em 0; }
.md blockquote {
  margin: 0.8em 0;
  padding: 4px 16px;
  border-left: 3px solid var(--md-primary);
  background: var(--md-surface-container);
  color: var(--md-on-surface-variant);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.md code {
  font-family: var(--mono);
  font-size: 0.88em;
  padding: 2px 6px;
  border-radius: var(--radius-xs);
  background: var(--md-surface-container-high);
  color: var(--md-on-surface);
}
.md pre {
  margin: 0.9em 0;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  background: var(--md-surface-container-highest);
  overflow-x: auto;
  line-height: 1.6;
}
.md pre code { padding: 0; background: none; font-size: 13px; }
.md table { border-collapse: collapse; margin: 0.9em 0; width: 100%; font-size: 14px; }
.md th, .md td { border: 1px solid var(--md-outline-variant); padding: 8px 12px; text-align: left; }
.md th { background: var(--md-surface-container-high); font-weight: 600; }
.md img { max-width: 100%; height: auto; border-radius: var(--radius-sm); }
.md hr { border: none; border-top: 1px solid var(--md-outline-variant); margin: 1.4em 0; }
.md .katex-display { overflow-x: auto; overflow-y: hidden; padding: 2px 0; }
.md a { text-decoration: underline; text-underline-offset: 2px; }

/* ---------- 上传 ---------- */

.dropzone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 22px;
  border: 1.5px dashed var(--md-outline);
  border-radius: var(--radius-md);
  background: var(--md-surface-container-lowest);
  color: var(--md-on-surface-variant);
  font-size: 13px;
  text-align: center;
  cursor: pointer;
  transition: border-color 140ms ease, background-color 140ms ease;
}
.dropzone:hover, .dropzone--over { border-color: var(--md-primary); background: color-mix(in srgb, var(--md-primary) 6%, var(--md-surface-container-lowest)); }
.dropzone__icon { font-size: 26px; line-height: 1; }

.file-list { display: flex; flex-direction: column; gap: 8px; margin-top: 10px; }
.file-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-sm);
  background: var(--md-surface-container-lowest);
  font-size: 13px;
}
.file-item__thumb { width: 40px; height: 40px; border-radius: var(--radius-xs); object-fit: cover; flex: none; background: var(--md-surface-container-high); display: grid; place-items: center; }
.file-item__name { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.file-item__size { color: var(--md-on-surface-variant); font-size: 12px; flex: none; }

.media-preview { width: 100%; max-height: 320px; border-radius: var(--radius-sm); background: #000; }

/* ---------- 进度 / 提示 ---------- */

.progress {
  height: 6px;
  border-radius: var(--radius-full);
  background: var(--md-surface-container-highest);
  overflow: hidden;
}
.progress__bar { height: 100%; background: var(--md-primary); transition: width 200ms ease; }

.banner {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  font-size: 14px;
}
.banner--info { background: var(--md-secondary-container); color: var(--md-on-secondary-container); }
.banner--warn { background: var(--md-warning-container); color: var(--md-warning); }
.banner--error { background: var(--md-error-container); color: var(--md-on-error-container); }
.banner--success { background: var(--md-success-container); color: var(--md-on-success-container); }

.empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 56px 24px;
  text-align: center;
  color: var(--md-on-surface-variant);
}
.empty__icon { font-size: 40px; opacity: 0.55; }
.empty__title { font-size: 16px; font-weight: 500; color: var(--md-on-surface); }

/* ---------- 表格 ---------- */

.table-wrap { overflow-x: auto; border: 1px solid var(--md-outline-variant); border-radius: var(--radius-md); }
table.data { width: 100%; border-collapse: collapse; font-size: 14px; }
table.data th, table.data td { padding: 12px 16px; text-align: left; border-bottom: 1px solid var(--md-outline-variant); }
table.data th { background: var(--md-surface-container); font-weight: 500; font-size: 13px; color: var(--md-on-surface-variant); white-space: nowrap; }
table.data tr:last-child td { border-bottom: none; }
table.data tbody tr:hover { background: var(--md-surface-container); }

/* ---------- 对话框 ---------- */

.scrim {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: grid;
  place-items: center;
  padding: 20px;
  background: var(--md-scrim);
  animation: fade 120ms ease;
}
.dialog {
  width: min(560px, 100%);
  max-height: min(86vh, 900px);
  overflow: auto;
  padding: 24px;
  border-radius: var(--radius-xl);
  background: var(--md-surface-container-high);
  box-shadow: var(--elev-3);
  animation: pop 140ms cubic-bezier(0.2, 0, 0, 1);
}
.dialog__title { margin: 0 0 12px; font-size: 20px; font-weight: 400; }
.dialog__body { font-size: 14px; color: var(--md-on-surface-variant); }
.dialog__actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 20px; flex-wrap: wrap; }

@keyframes fade { from { opacity: 0; } }
@keyframes pop { from { opacity: 0; transform: scale(0.96); } }

/* ---------- 提示条 ---------- */

#snackbar-host {
  position: fixed;
  left: 50%;
  bottom: 24px;
  z-index: 120;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
  pointer-events: none;
  width: min(92vw, 480px);
}
.snackbar {
  width: 100%;
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  background: var(--md-inverse-surface);
  color: var(--md-inverse-on-surface);
  font-size: 14px;
  box-shadow: var(--elev-2);
  animation: rise 160ms cubic-bezier(0.2, 0, 0, 1);
}
.snackbar--error { background: var(--md-error); color: var(--md-on-primary); }
@keyframes rise { from { opacity: 0; transform: translateY(12px); } }

/* ---------- 登录页 ---------- */

.auth-wrap {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  background:
    radial-gradient(1200px 600px at 10% -10%, color-mix(in srgb, var(--md-primary) 18%, transparent), transparent),
    radial-gradient(900px 500px at 110% 110%, color-mix(in srgb, var(--md-tertiary) 16%, transparent), transparent),
    var(--md-surface);
}
.auth-card {
  width: min(400px, 100%);
  padding: 32px 28px;
  border-radius: var(--radius-xl);
  background: var(--md-surface-container-low);
  border: 1px solid var(--md-outline-variant);
  box-shadow: var(--elev-2);
}
.auth-card__logo {
  width: 48px; height: 48px;
  display: grid; place-items: center;
  border-radius: var(--radius-md);
  background: var(--md-primary);
  color: var(--md-on-primary);
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 18px;
}
.auth-card h1 { margin: 0 0 6px; font-size: 24px; font-weight: 400; }
.auth-card p.sub { margin: 0 0 24px; font-size: 14px; color: var(--md-on-surface-variant); }

/* ---------- 其他 ---------- */

.divider { height: 1px; background: var(--md-outline-variant); border: none; margin: 4px 0; }
.muted { color: var(--md-on-surface-variant); }
.small { font-size: 13px; }
.tiny { font-size: 12px; }
.mono { font-family: var(--mono); }
.nowrap { white-space: nowrap; }
.center { text-align: center; }
.hidden { display: none !important; }

.loading {
  display: grid;
  place-items: center;
  padding: 64px;
  color: var(--md-on-surface-variant);
}
.spinner {
  width: 28px; height: 28px;
  border: 3px solid var(--md-outline-variant);
  border-top-color: var(--md-primary);
  border-radius: 50%;
  animation: spin 700ms linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.segmented {
  display: inline-flex;
  padding: 3px;
  gap: 2px;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-full);
  background: var(--md-surface-container);
}
.segmented button {
  border: none;
  background: transparent;
  color: var(--md-on-surface-variant);
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  cursor: pointer;
}
.segmented button[aria-pressed="true"] { background: var(--md-primary); color: var(--md-on-primary); }

.score-badge {
  display: inline-flex;
  align-items: baseline;
  gap: 3px;
  font-variant-numeric: tabular-nums;
  font-weight: 600;
}
.score-badge__value { font-size: 20px; }
.score-badge__total { font-size: 13px; color: var(--md-on-surface-variant); font-weight: 400; }

.sticky-actions {
  position: sticky;
  bottom: 0;
  z-index: 20;
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: flex-end;
  padding: 12px 16px;
  margin: 0 -16px -96px;
  background: color-mix(in srgb, var(--md-surface) 92%, transparent);
  backdrop-filter: blur(10px);
  border-top: 1px solid var(--md-outline-variant);
}

.editor-toolbar { display: flex; gap: 4px; flex-wrap: wrap; align-items: center; }

@media (max-width: 720px) {
  .topbar { padding: 0 4px; }
  .topbar__nav { display: none; }
  .topbar__brand span { display: none; }
  .page { padding: 16px 12px 96px; }
  .page-title { font-size: 22px; }
  .asg-card { flex-direction: column; gap: 10px; }
  .asg-card__side { align-items: flex-start; flex-direction: row; }
  .q { padding: 16px; }
  .sticky-actions { margin: 0 -12px -96px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

@media print {
  .topbar, .sticky-actions, .page-actions { display: none !important; }
  body { background: #fff; color: #000; }
  .q, .card { break-inside: avoid; border-color: #ccc; }
}