/* ================================================================
 * CDA Level II 备考系统 · 浅蓝色系主题
 * 依 generic-exam-prep 蓝图 + css-essentials.css 模板
 * ================================================================ */

:root {
  --c-primary: #2f80ed;
  --c-primary-d: #1f66c8;
  --c-primary-l: #56ccf2;
  --c-bg: #f2f7fd;
  --c-surface: #ffffff;
  --c-surface-2: #e8f2fe;
  --c-line: #d5e6f9;
  --c-text: #16324f;
  --c-text-2: #5b7c9d;
  --c-success: #27ae60;
  --c-danger: #eb5757;
  --c-warn: #f2994a;
  --c-shadow: 0 2px 10px rgba(47, 128, 237, .08);
  --rail-w: clamp(220px, 18vw, 262px);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0; background: var(--c-bg); color: var(--c-text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 15px; line-height: 1.6;
  /* 滚动解耦：页面本身不滚，左侧导航与右侧正文各自独立滚动，互不牵动 */
  overflow: hidden;
  -webkit-text-size-adjust: 100%;
}

/* ===== P2：强制隐藏（遮罩关闭后必须真的消失） ===== */
.hidden, [hidden] { display: none !important; }

/* ================= 侧栏 ================= */
#sidebar {
  position: fixed; top: 0; left: 0; bottom: 0; width: var(--rail-w);
  background: var(--c-surface); border-right: 1px solid var(--c-line);
  display: flex; flex-direction: column; z-index: 40; overflow: hidden;
}
.brand {
  display: flex; align-items: center; gap: 10px; padding: 18px 16px 14px;
  border-bottom: 1px solid var(--c-line);
  background: linear-gradient(135deg, #eaf3ff, #f7fbff);
}
.brand-logo { font-size: 24px; }
.brand-title { font-size: 16px; font-weight: 800; letter-spacing: .2px; }
.brand-sub { font-size: 12px; color: var(--c-text-2); }

#subjbar {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 16px; background: var(--c-surface); border-bottom: 1px solid var(--c-line);
}
.subj-label { font-weight: 700; color: var(--c-text-2); font-size: 13px; white-space: nowrap; }
.subj-select, .filter-select {
  appearance: none; -webkit-appearance: none; flex: 1; min-width: 0;
  min-height: 38px; padding: 0 12px; font-size: 14px;
  border: 1px solid var(--c-line); border-radius: 10px; background: var(--c-surface-2);
  color: var(--c-text);
}
.subj-select:disabled { opacity: .75; }

/* overscroll-behavior: contain —— 导航滚到尽头后不把滚动传递给正文（杜绝"同步滚动"错觉） */
.nav {
  flex: 1; overflow-y: auto; padding: 10px 10px 20px;
  overscroll-behavior: contain; -webkit-overflow-scrolling: touch;
}
.nav-item, .nav-parent {
  display: flex; align-items: center; gap: 10px; width: 100%;
  padding: 10px 12px; margin-bottom: 4px; border: none; background: transparent;
  border-radius: 10px; font-size: 14.5px; color: var(--c-text); text-align: left;
  cursor: pointer; font-family: inherit;
}
.nav-item:hover, .nav-parent:hover { background: var(--c-surface-2); }
.nav-item.active { background: var(--c-primary); color: #fff; font-weight: 700; }
.nav-ico { width: 20px; text-align: center; flex: 0 0 20px; }
.nav-label { flex: 1; }
.nav-badge {
  min-width: 20px; padding: 0 6px; height: 20px; line-height: 20px; text-align: center;
  background: var(--c-danger); color: #fff; border-radius: 10px; font-size: 11px; font-weight: 700;
}
.nav-item.active .nav-badge { background: #fff; color: var(--c-primary); }
.nav-caret { font-size: 11px; color: var(--c-text-2); transition: transform .2s; }
.has-sub.open > .nav-parent .nav-caret { transform: rotate(90deg); }
.nav-sub { display: none; padding: 0 0 6px 30px; }
.has-sub.open > .nav-sub { display: block; }
.nav-sub-item {
  display: flex; align-items: center; width: 100%; text-align: left; border: none; background: transparent;
  padding: 8px 10px; border-radius: 8px; font-size: 13.5px; color: var(--c-text-2);
  cursor: pointer; font-family: inherit;
}
.nav-sub-item .nav-weight { margin-left: auto; font-size: 11px; font-weight: 600; color: var(--c-primary); opacity: .8; white-space: nowrap; }
.nav-sub-item:hover { background: var(--c-surface-2); color: var(--c-text); }
.nav-sub-item.active { background: var(--c-surface-2); color: var(--c-primary); font-weight: 700; }
.nav-sub-hint { padding: 8px 10px; font-size: 12.5px; color: var(--c-text-2); }

.side-foot { padding: 12px 16px; border-top: 1px solid var(--c-line); }
.sf-line { font-size: 11.5px; color: var(--c-text-2); }

.rail-overlay {
  position: fixed; inset: 0; background: rgba(22, 50, 79, .35); z-index: 35; display: none;
}
.rail-overlay.show { display: block; }

/* ================= 主区 ================= */
/* 正文自成滚动容器：滚动它不会带动左侧导航，导航滚动也不会带动它 */
#main {
  margin-left: var(--rail-w); display: flex; flex-direction: column;
  height: 100vh; height: 100dvh; overflow-y: auto; overflow-x: hidden;
  overscroll-behavior: contain; -webkit-overflow-scrolling: touch;
}
#topbar {
  position: sticky; top: 0; z-index: 30;
  display: flex; align-items: center; gap: 12px;
  padding: 12px 20px; background: rgba(255, 255, 255, .94);
  backdrop-filter: saturate(160%) blur(8px);
  border-bottom: 1px solid var(--c-line);
}
.rail-toggle {
  display: none; border: 1px solid var(--c-line); background: var(--c-surface);
  border-radius: 10px; width: 40px; height: 38px; font-size: 17px; cursor: pointer; color: var(--c-text);
}
.top-title { font-size: 16px; font-weight: 700; }
.user-box { margin-left: auto; display: flex; align-items: center; gap: 10px; font-size: 14px; }
.user-hi { color: var(--c-text-2); }
.user-hi b { color: var(--c-text); }

.view { flex: 1; width: 100%; max-width: min(1100px, 100%); margin: 0 auto; padding: 20px; }

/* ================= 通用组件 ================= */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: 40px; padding: 0 16px; border: none; border-radius: 10px;
  background: var(--c-primary); color: #fff; font-size: 14.5px; font-weight: 700;
  cursor: pointer; font-family: inherit;
}
.btn:hover { background: var(--c-primary-d); }
.btn.ghost { background: var(--c-surface-2); color: var(--c-primary); }
.btn.ghost:hover { background: #d9e9fc; }
.btn.danger { background: var(--c-danger); }
.btn.tiny { min-height: 34px; padding: 0 12px; font-size: 13px; }
.btn.block { display: flex; width: 100%; }
.btn:disabled { opacity: .55; cursor: not-allowed; }

.card {
  background: var(--c-surface); border: 1px solid var(--c-line);
  border-radius: 14px; padding: 18px; box-shadow: var(--c-shadow);
}
.page-title { font-size: 20px; font-weight: 800; margin: 0 0 4px; }
.page-sub { font-size: 13px; color: var(--c-text-2); margin: 0 0 16px; }

.toast {
  position: fixed; left: 50%; bottom: 40px; transform: translateX(-50%);
  background: rgba(22, 50, 79, .92); color: #fff; padding: 10px 18px;
  border-radius: 22px; font-size: 14px; z-index: 90; max-width: 80vw; text-align: center;
}

/* 弹窗（P2） */
.modal-mask { position: fixed; inset: 0; background: rgba(22, 50, 79, .42); display: grid; place-items: center; z-index: 60; padding: 20px; }
.modal { background: var(--c-surface); border-radius: 16px; padding: 22px; width: min(420px, 92vw); box-shadow: 0 20px 60px rgba(22, 50, 79, .25); }
.modal-title { margin: 0 0 6px; font-size: 18px; }
.modal-sub { margin: 0 0 14px; color: var(--c-text-2); font-size: 13px; line-height: 1.6; }
.modal-input { width: 100%; min-height: 44px; padding: 0 12px; font-size: 16px; border: 1px solid var(--c-line); border-radius: 10px; font-family: inherit; }
.modal-actions { display: flex; gap: 10px; justify-content: flex-end; margin-top: 14px; }
.modal-err { color: var(--c-danger); font-size: 13px; min-height: 18px; margin: 8px 0 0; }

/* 状态盒（P12） */
.state-box { text-align: center; padding: 56px 20px; color: var(--c-text-2); }
.state-box .ico { font-size: 40px; display: block; margin-bottom: 12px; }
.state-box .msg { font-size: 15px; margin-bottom: 6px; color: var(--c-text); }
.state-box .sub { font-size: 13px; margin-bottom: 18px; max-width: 420px; margin-left: auto; margin-right: auto; word-break: break-all; }
.state-actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.loading-box { text-align: center; padding: 60px 20px; color: var(--c-text-2); }
.spinner {
  width: 30px; height: 30px; border: 3px solid var(--c-surface-2);
  border-top-color: var(--c-primary); border-radius: 50%;
  animation: spin .8s linear infinite; margin: 0 auto 12px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ================= 备考中心 dashboard ================= */
.login-banner {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  background: linear-gradient(135deg, #e3f0ff, #f4f9ff);
  border: 1px solid var(--c-line); border-radius: 14px; padding: 14px 18px; margin-bottom: 16px;
}
.login-banner .lb-text { flex: 1; min-width: 180px; font-size: 14px; }
.hero {
  background: linear-gradient(135deg, var(--c-primary), var(--c-primary-l));
  color: #fff; border-radius: 16px; padding: 24px; margin-bottom: 18px;
}
.hero h2 { margin: 0 0 6px; font-size: 22px; }
.hero .hero-date { font-size: 13px; opacity: .9; margin-bottom: 16px; }
.hero .btn { background: #fff; color: var(--c-primary); }
.hero .btn:hover { background: #eaf3ff; }
.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 12px; margin-bottom: 18px; }
.stat { background: var(--c-surface); border: 1px solid var(--c-line); border-radius: 12px; padding: 14px; text-align: center; }
.stat-n { font-size: 22px; font-weight: 800; color: var(--c-primary); }
.stat-l { font-size: 12px; color: var(--c-text-2); }

.mod-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 14px; }
.mod-card {
  position: relative; text-align: left; border: 1px solid var(--c-line);
  background: var(--c-surface); border-radius: 14px; padding: 18px;
  cursor: pointer; font-family: inherit; color: var(--c-text);
  transition: transform .15s, border-color .15s, box-shadow .15s;
}
.mod-card:hover { transform: translateY(-2px); border-color: var(--c-primary); box-shadow: var(--c-shadow); }
.mod-ico { font-size: 26px; display: block; margin-bottom: 8px; }
.mod-name { font-size: 15.5px; font-weight: 700; margin-bottom: 4px; }
.mod-desc { font-size: 12.5px; color: var(--c-text-2); }
.mod-badge {
  position: absolute; top: 12px; right: 12px; min-width: 22px; height: 22px; line-height: 22px;
  padding: 0 7px; text-align: center; background: var(--c-danger); color: #fff;
  border-radius: 11px; font-size: 11px; font-weight: 700;
}

/* ================= 章节刷题 ================= */
.rail-wide { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.chapter-card {
  display: flex; flex-direction: column; gap: 8px; text-align: left;
  border: 1px solid var(--c-line); background: var(--c-surface); border-radius: 14px;
  padding: 16px; cursor: pointer; font-family: inherit; color: var(--c-text);
  transition: transform .15s, border-color .15s;
}
.chapter-card:hover { transform: translateY(-2px); border-color: var(--c-primary); }
.cc-name { font-size: 15px; font-weight: 700; }
.cc-meta { font-size: 12.5px; color: var(--c-text-2); }
.cc-progress { height: 6px; background: var(--c-surface-2); border-radius: 3px; overflow: hidden; }
.cc-progress i { display: block; height: 100%; background: var(--c-primary); border-radius: 3px; }
.cc-cta { font-size: 13px; color: var(--c-primary); font-weight: 700; }

/* ================= 答题卡 ================= */
.q-wrap { max-width: 860px; margin: 0 auto; }
.q-head { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-bottom: 12px; flex-wrap: wrap; }
.q-pos { font-size: 13px; color: var(--c-text-2); }
.q-tags { display: flex; gap: 6px; flex-wrap: wrap; }
.q-tag { font-size: 11.5px; font-weight: 700; padding: 2px 9px; border-radius: 9px; background: var(--c-surface-2); color: var(--c-primary); }
.q-tag.lv { background: #fff3e0; color: #c77700; }
.q-card { background: var(--c-surface); border: 1px solid var(--c-line); border-radius: 14px; padding: 20px; box-shadow: var(--c-shadow); }
.q-passage {
  background: var(--c-surface-2); border-left: 3px solid var(--c-primary);
  border-radius: 0 10px 10px 0; padding: 12px 14px; margin-bottom: 14px; font-size: 14px; line-height: 1.75;
}
.q-passage-t { font-size: 12px; font-weight: 700; color: var(--c-primary); margin-bottom: 4px; }
.q-text { font-size: 16px; line-height: 1.75; margin-bottom: 14px; }
.q-text p, .q-passage p { margin: 0 0 8px; }
.q-text p:last-child, .q-passage p:last-child { margin-bottom: 0; }
.opts { display: flex; flex-direction: column; gap: 10px; }
.opt {
  display: flex; align-items: flex-start; gap: 10px; width: 100%; text-align: left;
  padding: 12px 14px; border: 1px solid var(--c-line); border-radius: 12px;
  background: var(--c-surface); cursor: pointer; font-family: inherit;
  font-size: 14.5px; color: var(--c-text); line-height: 1.6;
}
.opt:hover { border-color: var(--c-primary); }
.opt.sel { border-color: var(--c-primary); background: var(--c-surface-2); }
.opt.ok { border-color: var(--c-success); background: #e8f8ef; }
.opt.no { border-color: var(--c-danger); background: #fdeaea; }
.opt:disabled { cursor: default; }
.opt-l {
  flex: 0 0 26px; width: 26px; height: 26px; border-radius: 50%; background: var(--c-surface-2);
  color: var(--c-primary); font-weight: 800; font-size: 13px;
  display: inline-flex; align-items: center; justify-content: center;
}
.opt.sel .opt-l { background: var(--c-primary); color: #fff; }
.opt.ok .opt-l { background: var(--c-success); color: #fff; }
.opt.no .opt-l { background: var(--c-danger); color: #fff; }
.opt-t { flex: 1; }

.q-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 16px; }
.q-actions .btn { flex: 1; min-width: 110px; }
.fav-btn { flex: 0 0 auto !important; min-width: 52px !important; }

.reveal { display: none; margin-top: 16px; border-top: 1px dashed var(--c-line); padding-top: 14px; }
.reveal.show { display: block; }
.complete-tip { margin-top: 14px; padding: 12px 14px; border-radius: 10px; background: var(--c-success-bg, #e8f7ee); color: var(--c-success, #1a9c5b); font-weight: 700; font-size: 14px; text-align: center; }
.rv-line { font-size: 14px; margin-bottom: 8px; }
.rv-k { font-weight: 700; color: var(--c-text-2); }
.rv-ok { color: var(--c-success); font-weight: 800; }
.rv-no { color: var(--c-danger); font-weight: 800; }
.rv-analysis { background: var(--c-surface-2); border-radius: 10px; padding: 12px 14px; font-size: 14px; line-height: 1.8; }
.rv-analysis p { margin: 0 0 8px; }
.rv-analysis p:last-child { margin-bottom: 0; }
.rv-analysis table { border-collapse: collapse; width: 100%; margin: 8px 0; font-size: 13px; }
.rv-analysis th, .rv-analysis td { border: 1px solid var(--c-line); padding: 6px 8px; }
.rv-analysis th { background: var(--c-surface); }

/* ================= 考试模式 ================= */
.exambar {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  background: var(--c-surface); border: 1px solid var(--c-line); border-radius: 12px;
  padding: 10px 16px; margin-bottom: 14px; flex-wrap: wrap;
}
.exam-timer-wrap { display: flex; align-items: baseline; gap: 8px; }
.exam-timer { font-size: 22px; font-weight: 800; font-variant-numeric: tabular-nums; color: var(--c-primary); }
.exam-timer.warn { color: var(--c-danger); }
.exam-tip { font-size: 12px; color: var(--c-text-2); }
.exam-layout { display: grid; grid-template-columns: 172px 1fr; gap: 16px; align-items: start; }
/* 题号面板：钉在视口内独立滚动，滚它不牵动正文，滚正文也不牵动它 */
.exam-palette {
  background: var(--c-surface); border: 1px solid var(--c-line); border-radius: 12px;
  padding: 12px; position: sticky; top: 12px; max-height: calc(100vh - 120px); overflow-y: auto;
  overscroll-behavior: contain; -webkit-overflow-scrolling: touch;
}
.ep-title { font-size: 12px; color: var(--c-text-2); margin-bottom: 8px; }
.ep-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px; }
.ep-btn {
  aspect-ratio: 1 / 1; border: 1px solid var(--c-line); background: var(--c-surface);
  border-radius: 8px; font-size: 12px; cursor: pointer; color: var(--c-text-2); font-family: inherit; padding: 0;
}
.ep-btn.answered { background: var(--c-surface-2); color: var(--c-primary); border-color: #bcd9f8; font-weight: 700; }
.ep-btn.current { background: var(--c-primary); color: #fff; border-color: var(--c-primary); font-weight: 800; }

/* ================= 成绩单 ================= */
.result-head { text-align: center; margin-bottom: 20px; }
.ring { width: clamp(130px, 30vw, 170px); height: clamp(130px, 30vw, 170px); margin: 0 auto 12px; position: relative; }
.ring svg { transform: rotate(-90deg); width: 100%; height: 100%; }
.ring-txt {
  position: absolute; inset: 0; display: flex; flex-direction: column;
  align-items: center; justify-content: center;
}
.ring-n { font-size: 30px; font-weight: 800; color: var(--c-primary); }
.ring-l { font-size: 12px; color: var(--c-text-2); }
.res-grade { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.weak-list { margin-top: 16px; }
.weak-item { display: flex; align-items: center; gap: 10px; padding: 9px 0; border-bottom: 1px solid var(--c-line); font-size: 14px; }
.weak-name { flex: 1; }
.weak-bar { flex: 0 0 90px; height: 6px; background: var(--c-surface-2); border-radius: 3px; overflow: hidden; }
.weak-bar i { display: block; height: 100%; background: var(--c-primary); }
.weak-pct { flex: 0 0 46px; text-align: right; font-size: 13px; color: var(--c-text-2); }
.action-group, .complete-actions { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; margin-top: 18px; }

/* ================= 知识卡 ================= */
.kb-single { max-width: 680px; margin: 0 auto; display: flex; flex-direction: column; }
.kb-pos { text-align: center; font-size: 13px; color: var(--c-text-2); margin-bottom: 10px; }
/* 卡片高度随内容自适应：两面用 grid 叠放，只让「当前朝向」的那一面参与高度计算 */
.flashcard { perspective: 1600px; }
.flashcard-inner {
  position: relative; width: 100%; display: grid;
  transform-style: preserve-3d; transition: transform .5s; cursor: pointer;
}
.flashcard-inner.flipped { transform: rotateY(180deg); }
.flashcard-face {
  grid-area: 1 / 1; backface-visibility: hidden; -webkit-backface-visibility: hidden;
  border-radius: 16px; padding: 24px; background: var(--c-surface); border: 1px solid var(--c-line);
  box-shadow: var(--c-shadow);
}
/* 背面的内容不撑高正面，反之亦然 */
.flashcard-inner:not(.flipped) .fc-back { position: absolute; inset: 0; overflow: hidden; }
.flashcard-inner.flipped .fc-front { position: absolute; inset: 0; overflow: hidden; }
.fc-front {
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  text-align: center; min-height: clamp(240px, 38vh, 340px);
}
.fc-back { min-height: clamp(240px, 38vh, 340px); }
.fc-chapter { font-size: 12px; color: var(--c-primary); font-weight: 700; margin-bottom: 10px; }
.fc-title { font-size: clamp(19px, 4vw, 25px); font-weight: 800; line-height: 1.5; }
.fc-hint { margin-top: 18px; font-size: 12.5px; color: var(--c-text-2); }
.fc-back { transform: rotateY(180deg); }
.fc-back-t { font-size: 16px; font-weight: 800; margin-bottom: 10px; color: var(--c-primary); }
.article-body { line-height: 1.85; font-size: 14.5px; }
.article-body p { margin: 0 0 10px; }
.article-body ul, .article-body ol { margin: 0 0 10px; padding-left: 20px; }
.article-body li { margin-bottom: 4px; }
.article-body mark { background: #fff3bf; color: inherit; padding: 0 3px; border-radius: 3px; }
.article-body h4 { font-size: 14.5px; margin: 14px 0 6px; color: var(--c-primary); }
.article-body h4:first-child { margin-top: 0; }
.article-body hr { border: none; border-top: 1px dashed var(--c-line); margin: 12px 0; }
.article-body blockquote {
  margin: 10px 0; padding: 8px 12px; border-left: 3px solid var(--c-primary-l);
  background: var(--c-surface-2); border-radius: 0 8px 8px 0; color: var(--c-text-2); font-size: 13.5px;
}
.article-body blockquote p { margin: 0; }

/* ===== 彩色重点标注（受控白名单标签 <hl>/<key>/<warn>/<tip>） ===== */
mark.hl-hl   { background: #fff3bf; color: #8a6100; padding: 0 4px; border-radius: 4px; font-weight: 600; }
mark.hl-key  { background: #dbeafe; color: #1d4ed8; padding: 0 4px; border-radius: 4px; font-weight: 700; }
mark.hl-warn { background: #fee2e2; color: #b91c1c; padding: 0 4px; border-radius: 4px; font-weight: 600; }
mark.hl-tip  { background: #dcfce7; color: #15803d; padding: 0 4px; border-radius: 4px; font-weight: 600; }
.article-body table { border-collapse: collapse; width: 100%; margin: 10px 0; font-size: 13px; }
.article-body th, .article-body td { border: 1px solid var(--c-line); padding: 6px 8px; }
.article-body th { background: var(--c-surface-2); }
.stage-nav { display: flex; gap: 10px; margin-top: 14px; }
.stage-nav .btn { flex: 1; }
.fc-actions { display: flex; gap: 10px; margin-top: 10px; }
.fc-btn { flex: 1; min-height: 42px; border-radius: 12px; border: none; font-weight: 700; font-size: 14px; cursor: pointer; font-family: inherit; }
.fc-btn.yes { background: var(--c-success); color: #fff; }
.fc-btn.no { background: var(--c-surface-2); color: var(--c-text); }

/* ================= 错题本 / 收藏夹 ================= */
.mb-head { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-bottom: 14px; flex-wrap: wrap; }
.mb-title { font-size: 19px; font-weight: 800; margin: 0; }
.mb-page { text-align: center; font-size: 13px; color: var(--c-text-2); margin-bottom: 10px; }
.mb-meta { font-size: 12px; color: var(--c-text-2); margin-bottom: 8px; display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.mb-status { font-size: 11px; font-weight: 700; padding: 2px 8px; border-radius: 8px; }
.mb-status.act { background: #fdeaea; color: var(--c-danger); }
.mb-status.con { background: #e8f8ef; color: var(--c-success); }
.mb-status.wait { background: var(--c-surface-2); color: var(--c-primary); }
.mb-actions { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 14px; }
.seg { display: inline-flex; background: var(--c-surface-2); border-radius: 10px; padding: 3px; gap: 3px; }
.seg button { border: none; background: transparent; padding: 7px 14px; border-radius: 8px; font-size: 13px; cursor: pointer; color: var(--c-text-2); font-family: inherit; }
.seg button.on { background: var(--c-surface); color: var(--c-primary); font-weight: 700; box-shadow: var(--c-shadow); }

/* ================= 响应式三档 ================= */
@media (max-width: 1024px) {
  #sidebar { transform: translateX(-100%); transition: transform .25s; width: min(280px, 84vw); }
  #sidebar.open { transform: translateX(0); box-shadow: 0 0 40px rgba(22, 50, 79, .2); }
  #main { margin-left: 0; }
  .rail-toggle { display: block; }
  .exam-layout { grid-template-columns: 1fr; }
  /* 窄屏单列：题号面板改为常规流，避免长期遮挡正文（此时不存在双栏同步滚动问题） */
  .exam-palette { position: static; max-height: 32vh; }
  .ep-grid { grid-template-columns: repeat(10, 1fr); }
}
@media (max-width: 640px) {
  body { font-size: 14.5px; }
  .view { padding: 14px; }
  .q-card { padding: 15px; }
  .hero { padding: 18px; }
  .hero h2 { font-size: 19px; }
  .q-actions .btn { width: 100%; flex: 1 1 100%; }
  .fav-btn { flex: 1 1 100% !important; }
  .ep-grid { grid-template-columns: repeat(6, 1fr); }
  .mod-grid { grid-template-columns: 1fr 1fr; }
  .mod-card { padding: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  .flashcard-inner, .mod-card, .chapter-card, #sidebar { transition: none !important; }
}