/* ==========================================================================
   CET-6 六级冲刺 · 移动端样式（平板/手机优先）
   ========================================================================== */
:root {
  --bg: #0e1116;
  --bg2: #161b22;
  --card: #1a2029;
  --card2: #212936;
  --line: #2b3441;
  --fg: #e8edf4;
  --fg2: #9aa7b8;
  --fg3: #67728a;
  --acc: #4d9fff;
  --acc2: #2b7fe0;
  --ok: #35c98a;
  --bad: #ff6b6b;
  --warn: #ffb648;
  --gold: #ffd166;
  --r: 14px;
  --tap: 46px;
  --safeb: env(safe-area-inset-bottom, 0px);
}
html[data-theme="light"] {
  --bg: #f4f6fa; --bg2: #ffffff; --card: #ffffff; --card2: #f0f3f8;
  --line: #e2e7ef; --fg: #16202c; --fg2: #5b6a7d; --fg3: #8a97a8;
  --acc: #1f6feb; --acc2: #1558c0;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg); color: var(--fg);
  font: 15px/1.62 -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
  -webkit-font-smoothing: antialiased;
  overscroll-behavior-y: none;
}
a { color: var(--acc); text-decoration: none; }
button, input, textarea, select { font-family: inherit; font-size: inherit; color: inherit; }
img { max-width: 100%; display: block; }
::selection { background: var(--acc); color: #fff; }
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-thumb { background: var(--line); border-radius: 3px; }

/* ---------- 布局骨架 ---------- */
#app { display: flex; flex-direction: column; min-height: 100svh; }
.topbar {
  position: sticky; top: 0; z-index: 40;
  display: flex; align-items: center; gap: 10px;
  padding: 10px 14px; padding-top: calc(10px + env(safe-area-inset-top, 0px));
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.topbar .brand { display: flex; align-items: center; gap: 8px; font-weight: 700; letter-spacing: .2px; }
.topbar .brand .dot {
  width: 28px; height: 28px; border-radius: 9px; display: grid; place-items: center;
  background: linear-gradient(140deg, var(--acc), #7b5cff); color: #fff; font-size: 12px; font-weight: 800;
}
.topbar .sp { flex: 1; }
.cd {
  font-variant-numeric: tabular-nums; font-weight: 700; font-size: 13px;
  background: var(--card); border: 1px solid var(--line); border-radius: 999px;
  padding: 5px 11px; white-space: nowrap;
}
.cd.warn { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 45%, var(--line)); }
.cd.hot { color: var(--bad); border-color: color-mix(in srgb, var(--bad) 45%, var(--line)); }

main { flex: 1; padding: 14px 14px calc(84px + var(--safeb)); max-width: 980px; width: 100%; margin: 0 auto; }

/* ---------- 底部导航 ---------- */
.tabbar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 45;
  display: grid; grid-template-columns: repeat(5, 1fr);
  background: color-mix(in srgb, var(--bg2) 92%, transparent);
  backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
  border-top: 1px solid var(--line);
  padding-bottom: var(--safeb);
}
.tabbar a {
  display: flex; flex-direction: column; align-items: center; gap: 3px;
  padding: 9px 0 7px; color: var(--fg3); font-size: 11px; font-weight: 600;
}
.tabbar a .ti { font-size: 19px; line-height: 1; }
.tabbar a.on { color: var(--acc); }
.tabbar a.on .ti { transform: translateY(-1px); }

/* ---------- 通用组件 ---------- */
.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--r); padding: 14px; margin-bottom: 12px;
}
.card.tight { padding: 11px 12px; }
.card h2 { margin: 0 0 4px; font-size: 16px; }
.card h3 { margin: 0 0 6px; font-size: 15px; }
h1.page { font-size: 20px; margin: 2px 0 12px; letter-spacing: .2px; }
h1.page small { font-weight: 400; color: var(--fg3); font-size: 12px; margin-left: 6px; }
.muted { color: var(--fg2); }
.tiny { font-size: 12px; color: var(--fg3); line-height: 1.55; }
.mt { margin-top: 10px; }
.mb { margin-bottom: 10px; }
.row { display: flex; align-items: center; gap: 10px; }
.row.wrap { flex-wrap: wrap; }
.grow { flex: 1; min-width: 0; }
.center { text-align: center; }
.nowrap { white-space: nowrap; }
.hr { height: 1px; background: var(--line); margin: 12px 0; }
.hidden { display: none !important; }

button.btn, .btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: var(--tap); padding: 0 16px; border-radius: 11px;
  border: 1px solid var(--line); background: var(--card2); color: var(--fg);
  font-weight: 650; font-size: 14.5px; cursor: pointer; user-select: none;
}
.btn:active { transform: scale(.985); }
.btn.pri { background: linear-gradient(180deg, var(--acc), var(--acc2)); border-color: transparent; color: #fff; }
.btn.ok { background: var(--ok); border-color: transparent; color: #04231a; }
.btn.bad { background: transparent; border-color: color-mix(in srgb, var(--bad) 55%, var(--line)); color: var(--bad); }
.btn.ghost { background: transparent; }
.btn.sm { min-height: 34px; padding: 0 11px; font-size: 13px; border-radius: 9px; }
.btn.blk { width: 100%; }
.btn[disabled] { opacity: .45; pointer-events: none; }
.btnrow { display: flex; gap: 8px; flex-wrap: wrap; }
.btnrow.eq > * { flex: 1; }

.chip {
  display: inline-flex; align-items: center; gap: 5px; padding: 5px 11px;
  border-radius: 999px; border: 1px solid var(--line); background: var(--card2);
  font-size: 13px; color: var(--fg2); cursor: pointer; white-space: nowrap;
}
.chip.on { background: var(--acc); border-color: transparent; color: #fff; }
.chips { display: flex; gap: 7px; overflow-x: auto; padding: 2px 0 6px; scrollbar-width: none; }
.chips::-webkit-scrollbar { display: none; }

.badge { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 11.5px; font-weight: 700; }
.badge.g { background: color-mix(in srgb, var(--ok) 20%, transparent); color: var(--ok); }
.badge.r { background: color-mix(in srgb, var(--bad) 20%, transparent); color: var(--bad); }
.badge.y { background: color-mix(in srgb, var(--warn) 20%, transparent); color: var(--warn); }
.badge.b { background: color-mix(in srgb, var(--acc) 20%, transparent); color: var(--acc); }

.bar { height: 8px; border-radius: 99px; background: var(--card2); overflow: hidden; }
.bar > i { display: block; height: 100%; background: linear-gradient(90deg, var(--acc), #7b5cff); border-radius: 99px; transition: width .35s; }
.bar.g > i { background: linear-gradient(90deg, var(--ok), #7de2b0); }
.bar.slim { height: 6px; }

.kpi { display: grid; grid-template-columns: repeat(auto-fit, minmax(76px, 1fr)); gap: 8px; }
.kpi .k { background: var(--card2); border-radius: 11px; padding: 9px 10px; }
.kpi .k b { display: block; font-size: 19px; font-variant-numeric: tabular-nums; }
.kpi .k span { font-size: 11.5px; color: var(--fg3); }

/* 任务卡 */
.task { display: flex; gap: 11px; align-items: flex-start; padding: 12px; border-radius: var(--r);
        background: var(--card); border: 1px solid var(--line); margin-bottom: 9px; }
.task .ic { font-size: 22px; line-height: 1.15; width: 30px; text-align: center; }
.task.done { opacity: .62; }
.task.done .t { text-decoration: line-through; text-decoration-color: var(--ok); }
.task .t { font-weight: 680; }

/* 题目 */
.qwrap { margin-bottom: 14px; }
.qstem { font-size: 16px; line-height: 1.6; margin: 6px 0 10px; }
.opts { display: flex; flex-direction: column; gap: 8px; }
.opt {
  display: flex; gap: 10px; align-items: flex-start; padding: 12px 13px; border-radius: 11px;
  border: 1.5px solid var(--line); background: var(--card); cursor: pointer; min-height: var(--tap);
  transition: border-color .12s, background .12s;
}
.opt .k {
  flex: 0 0 24px; height: 24px; border-radius: 50%; display: grid; place-items: center;
  background: var(--card2); font-size: 12.5px; font-weight: 800; color: var(--fg2);
}
.opt.sel { border-color: var(--acc); background: color-mix(in srgb, var(--acc) 10%, var(--card)); }
.opt.sel .k { background: var(--acc); color: #fff; }
.opt.right { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 12%, var(--card)); }
.opt.right .k { background: var(--ok); color: #05291d; }
.opt.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 12%, var(--card)); }
.opt.wrong .k { background: var(--bad); color: #2a0808; }
.opt.lock { pointer-events: none; }

.explain { margin-top: 9px; padding: 11px 12px; border-radius: 11px; background: var(--card2); border-left: 3px solid var(--acc); font-size: 13.5px; color: var(--fg2); }
.passage { font-size: 15px; line-height: 1.78; color: var(--fg); }
.passage p { margin: 0 0 10px; }
.transcript p { margin: 0 0 8px; }
.transcript .spk { font-weight: 800; color: var(--acc); margin-right: 4px; }

/* 闪卡 */
.flash { text-align: center; padding: 26px 16px; }
.flash .w { font-size: 34px; font-weight: 800; letter-spacing: -.5px; word-break: break-word; }
.flash .ph { color: var(--fg3); margin-top: 3px; font-size: 14px; }
.flash .cn { font-size: 19px; margin-top: 14px; line-height: 1.5; }
.flash .ex { margin-top: 14px; font-size: 14px; color: var(--fg2); font-style: italic; }
.flash .excn { font-size: 13px; color: var(--fg3); margin-top: 3px; font-style: normal; }

/* 试卷翻页 */
.pager { position: sticky; top: 52px; z-index: 20; display: flex; align-items: center; gap: 8px;
         background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: blur(10px);
         padding: 8px 0; margin-bottom: 8px; }
.pager .n { font-variant-numeric: tabular-nums; }
.paper-img { border-radius: 10px; border: 1px solid var(--line); background: #fff; }
.paper-img.zoom { cursor: zoom-in; }
#lightbox { position: fixed; inset: 0; z-index: 200; background: #000; display: flex; overflow: auto;
            -webkit-overflow-scrolling: touch; }
#lightbox img { margin: auto; max-width: none; }

/* 音频 */
audio { width: 100%; margin: 6px 0; }
.audiolist { display: flex; flex-direction: column; gap: 8px; }

/* 时间轴 / 历史 */
.hist { display: flex; gap: 4px; align-items: flex-end; height: 44px; }
.hist i { flex: 1; background: var(--card2); border-radius: 3px 3px 0 0; min-height: 3px; }
.hist i.has { background: var(--acc); }

/* 列表项 */
.li { display: flex; gap: 10px; align-items: center; padding: 11px 12px; border-radius: 11px;
      background: var(--card); border: 1px solid var(--line); margin-bottom: 8px; }
.li .g { flex: 1; min-width: 0; }
.li .t { font-weight: 640; }
.li .s { font-size: 12.5px; color: var(--fg3); }

/* 输入 */
input[type=text], input[type=datetime-local], input[type=number], textarea, select {
  width: 100%; background: var(--card2); border: 1px solid var(--line);
  border-radius: 10px; padding: 10px 12px; outline: none; color: var(--fg);
}
textarea { min-height: 120px; line-height: 1.6; resize: vertical; }
input:focus, textarea:focus { border-color: var(--acc); }

/* 弹层 */
.sheet { position: fixed; inset: 0; z-index: 120; display: flex; align-items: flex-end; justify-content: center; }
.sheet .bd { position: absolute; inset: 0; background: rgba(0,0,0,.5); }
.sheet .pn { position: relative; width: 100%; max-width: 620px; max-height: 88svh; overflow: auto;
             background: var(--bg2); border-radius: 18px 18px 0 0; padding: 16px 16px calc(18px + var(--safeb));
             border-top: 1px solid var(--line); }
.sheet .pn h3 { margin: 0 0 10px; }
@media (min-width: 700px) { .sheet { align-items: center; } .sheet .pn { border-radius: 18px; max-height: 84vh; } }

/* toast */
#toast { position: fixed; left: 50%; bottom: calc(96px + var(--safeb)); transform: translateX(-50%);
         z-index: 300; background: var(--card2); border: 1px solid var(--line); color: var(--fg);
         padding: 10px 16px; border-radius: 999px; font-size: 14px; box-shadow: 0 8px 26px rgba(0,0,0,.4);
         opacity: 0; transition: opacity .2s, transform .2s; pointer-events: none; max-width: 88vw; text-align: center; }
#toast.on { opacity: 1; transform: translateX(-50%) translateY(-4px); }

/* 安装提示 */
.install { border: 1px dashed color-mix(in srgb, var(--acc) 50%, var(--line));
           background: color-mix(in srgb, var(--acc) 8%, var(--card)); }

/* 大屏微调 */
@media (min-width: 760px) {
  main { padding-bottom: 30px; }
  .tabbar { position: sticky; bottom: 0; }
  #app { min-height: 100svh; }
}