:root {
  --primary: #1a73e8; --ok: #188038; --warn: #f9ab00; --bad: #d93025;
  --bg: #f5f6f8; --card: #fff; --ink: #202124; --sub: #5f6368; --line: #e3e5e8;
  --b1: #34a853; --b2: #1a73e8; --c1: #9334e6; --a2: #f29900;
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
/* 关键修复：.auth/.modal/.tabs/.unit-nav 都设了 display:flex，会覆盖浏览器的 [hidden] 默认
   display:none，导致带 hidden 的元素（登录门/账号弹窗/标签栏）始终显示、出现「双重方框」。 */
[hidden] { display: none !important; }
body { margin: 0; font-family: -apple-system, "PingFang SC", "Segoe UI", sans-serif;
       background: var(--bg); color: var(--ink); }
.wrap { max-width: 640px; margin: 0 auto; padding: 16px 16px 80px; }

header { position: sticky; top: 0; z-index: 10; background: var(--bg); padding: 12px 0 8px; }
h1 { font-size: 19px; margin: 0 0 2px; }
h2 { font-size: 17px; margin: 18px 0 8px; }
h3 { font-size: 15px; margin: 0 0 6px; }
.sub { font-size: 13px; color: var(--sub); margin-bottom: 8px; }
.tabs { display: flex; gap: 8px; }
.tab { flex: 1; padding: 9px 4px; border: 1px solid var(--line); border-radius: 10px;
       background: var(--card); text-align: center; cursor: pointer; font-size: 13px; }
.tab.active { border-color: var(--primary); color: var(--primary); font-weight: 600; }

/* 成绩单 */
.summary { display: none; background: var(--card); border: 1px solid var(--line); border-radius: 14px;
           padding: 14px; margin-top: 10px; }
.summary.show { display: block; }
.summary .row { display: flex; align-items: baseline; gap: 10px; }
.summary .big { font-size: 28px; font-weight: 700; }
.summary .weak { font-size: 13px; color: var(--sub); margin-top: 6px; }

/* 卡片 */
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px;
        padding: 16px; margin: 12px 0; box-shadow: 0 1px 3px rgba(0,0,0,.05); }
.card.locked { opacity: .45; pointer-events: none; }
.card.context { background: #fbfcfd; }
.cardhead { font-size: 12px; color: var(--sub); margin-bottom: 8px; display: flex;
            justify-content: space-between; align-items: center; gap: 8px; }
.chip { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 12px; color: #fff; white-space: nowrap; }
.chip.amy { background: #d56; } .chip.daniel { background: #4a6; } .chip.me { background: var(--primary); }
.chip.seller { background: #d56; } .chip.buyer { background: #4a6; }
.chip.michael { background: #7a6; }

/* 双册单元切换器（按册分组） */
.book-row { margin-bottom: 6px; }
.book-label { font-size: 12px; color: var(--sub); margin: 2px 0 4px; }
.tabs-inner { display: flex; gap: 8px; }

/* 通话分隔条（M4 双通话结构） */
.call-divider { margin: 20px 0 8px; padding: 8px 12px; font-size: 14px; font-weight: 600;
                color: var(--primary); background: #f2f6ff; border: 1px solid #d7e6ff;
                border-left: 4px solid var(--primary); border-radius: 8px; }

/* 听力实战 / 热身选择 */
.quiz-opts { display: flex; flex-direction: column; gap: 6px; margin-top: 8px; }
.quiz-opt { text-align: left; border-radius: 10px; }
.quiz-opt.opt-ok { border-color: var(--ok); background: #eefaf1; }
.quiz-opt.opt-bad { border-color: var(--warn); background: #fdf3ef; }
.opt-note { font-size: 13px; margin-top: 8px; padding: 8px 10px; border-radius: 8px; line-height: 1.6; }
.opt-note.ok { background: #eefaf1; border: 1px solid #cdeed6; }
.opt-note.bad { background: #fdf3ef; border: 1px solid #f5d9cd; }
.quiz-mc { margin: 12px 0; }
.sentence { font-size: 17px; line-height: 1.55; margin: 4px 0 14px; }
.sentence.zh { font-size: 14px; color: var(--sub); }
.badge { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 12px;
         font-weight: 600; color: #fff; background: var(--primary); }
.badge.B1 { background: var(--b1); } .badge.B2 { background: var(--b2); }
.badge.C1 { background: var(--c1); } .badge.A2 { background: var(--a2); }

/* 语言点注释 */
.keys { margin: 0 0 10px; display: flex; flex-wrap: wrap; gap: 6px; }
.key { font-size: 12px; background: #f2f6ff; border: 1px solid #d7e6ff; border-radius: 8px; padding: 4px 8px; }
.key b { color: var(--primary); }
.key .zh { color: var(--sub); }
/* 语言点详解（自学：释义 + 用法 + 例句） */
.keyblocks { margin: 0 0 10px; }
.key-block { font-size: 13px; background: #f2f6ff; border: 1px solid #d7e6ff; border-radius: 10px;
             padding: 8px 10px; margin: 6px 0; line-height: 1.6; }
.key-block b { color: var(--primary); }
.key-block .zh { color: var(--sub); }
.knote { font-size: 12px; color: var(--ink); margin-top: 4px; }
.kex { font-size: 13px; color: #444; margin-top: 4px; background: #fff;
       border-left: 3px solid #d7e6ff; padding: 4px 8px; border-radius: 4px; }
/* 范文精讲 */
.rp { margin: 12px 0; }
.rp-en { font-size: 15px; line-height: 1.6; font-family: Georgia, "Times New Roman", serif; }
.rp-zh { font-size: 13px; color: var(--sub); line-height: 1.6; margin: 4px 0 8px; }

/* 按钮 */
.btns { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
button { border: 1px solid var(--line); background: var(--card); color: var(--ink);
         border-radius: 999px; padding: 10px 16px; font-size: 14px; cursor: pointer; }
button:disabled { opacity: .4; cursor: not-allowed; }
button.primary { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }
button.rec { background: var(--bad); border-color: var(--bad); color: #fff; font-weight: 600; }
button.rec .dot { display: inline-block; width: 10px; height: 10px; border-radius: 50%;
                  background: #fff; margin-right: 6px; vertical-align: 1px; }
button.rec.on .dot { animation: pulse 1s infinite; }
@keyframes pulse { 50% { opacity: .25; } }
.timer { font-size: 14px; color: var(--bad); font-variant-numeric: tabular-nums; margin-left: 4px; }
.ghost { border: none; background: transparent; color: var(--primary); padding: 8px 10px; }

/* 评分结果 */
.result { display: none; margin-top: 14px; border-top: 1px dashed var(--line); padding-top: 12px; }
.result.show { display: block; }
.rtop { display: flex; align-items: baseline; gap: 10px; }
.rscore { font-size: 32px; font-weight: 700; }
.cefr { padding: 3px 10px; border-radius: 999px; color: #fff; font-size: 13px; font-weight: 600; }
.cefr.B1 { background: var(--b1); } .cefr.B2 { background: var(--b2); }
.cefr.C1 { background: var(--c1); } .cefr.A2 { background: var(--a2); }
.dims { margin-top: 10px; }
.dim { display: grid; grid-template-columns: 62px 1fr 34px; gap: 8px; align-items: center; margin: 6px 0; }
.dim .name { font-size: 13px; }
.dim .bar { height: 8px; background: var(--line); border-radius: 4px; overflow: hidden; }
.dim .bar i { display: block; height: 100%; border-radius: 4px; width: 0; transition: width .5s; }
.dim .val { font-size: 13px; font-weight: 600; text-align: right; }
.dim .tip { grid-column: 2 / 4; font-size: 12px; color: var(--sub); margin-top: -2px; }
.sim { font-size: 11px; color: #999; }
.words { margin-top: 10px; font-size: 15px; line-height: 2.1; }
.words span { padding: 1px 3px; border-radius: 4px; }
.w-ok { background: #e6f4ea; } .w-mid { background: #fef7e0; } .w-bad { background: #fce8e6; }
.transcript { margin-top: 8px; font-size: 13px; color: var(--sub); }

/* 课程视图 */
.collapse-head { cursor: pointer; user-select: none; }
.collapse-head::after { content: "▾"; float: right; color: var(--sub); }
.collapse-head.closed::after { content: "▸"; }
.collapse-body { display: block; }
.collapse-body.closed { display: none; }
table { width: 100%; border-collapse: collapse; font-size: 13px; }
th, td { text-align: left; padding: 7px 8px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--sub); font-weight: 500; }
td.en { font-weight: 600; }
/* 跨文化对照卡（5 国 × 维度，窄列自动换行） */
table.culture { table-layout: fixed; font-size: 12px; }
table.culture th, table.culture td { padding: 6px 5px; line-height: 1.5; word-break: break-word; }
table.culture th { color: var(--sub); font-weight: 600; background: #fbfcfd; }
table.culture .c-dim { width: 64px; color: var(--ink); font-weight: 600; background: #f2f6ff; }
.bank-item { padding: 8px 0; border-bottom: 1px dashed var(--line); display: flex; gap: 8px; }
.bank-item:last-child { border-bottom: none; }
.bank-item .en { font-size: 15px; line-height: 1.5; flex: 1; }
.bank-item .zh { font-size: 13px; color: var(--sub); }
.style-tag { flex: 0 0 26px; font-size: 15px; }

/* 精听（打字听写） */
.dict-input-row { display: flex; gap: 8px; margin: 4px 0 12px; }
.dict-input { flex: 1; min-width: 0; border: 1px solid var(--line); border-radius: 10px;
              padding: 10px 12px; font-size: 15px; font-family: inherit; }
.dict-input:focus { outline: none; border-color: var(--primary); }
.dict-diff { margin-top: 10px; font-size: 15px; line-height: 2.1; }
.dict-line { margin: 6px 0; }
.dict-line .sim { display: inline-block; width: 34px; vertical-align: top; }
.dict-line span:not(.sim) { padding: 1px 3px; border-radius: 4px; }
.sentence.dim { color: #b6b9bd; }

/* 其他 */
.rolepick { background: var(--card); border: 1px solid var(--line); border-radius: 14px;
            padding: 16px; margin: 12px 0; }
.rolepick p { font-size: 13px; color: var(--sub); margin: 0 0 10px; }
.rolepick button { width: 100%; margin: 4px 0; }
.hint { font-size: 13px; color: var(--sub); background: #f2f6ff; border-radius: 8px;
        padding: 8px 10px; margin: 0 0 12px; }
footer { font-size: 12px; color: #999; line-height: 1.7; margin-top: 24px; }
footer code { background: #eee; border-radius: 4px; padding: 1px 4px; }
.spinner { display: inline-block; width: 14px; height: 14px; border: 2px solid #fff;
           border-top-color: transparent; border-radius: 50%; animation: spin 0.8s linear infinite;
           vertical-align: -2px; margin-right: 6px; }
@keyframes spin { to { transform: rotate(360deg); } }
.error-box { background: #fce8e6; color: var(--bad); font-size: 13px; border-radius: 8px;
             padding: 8px 10px; margin-top: 10px; }

/* ---------- 首页课程树 ---------- */
.brand { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.home-btn { flex: 0 0 auto; }
.unit-nav { display: flex; align-items: center; gap: 8px; margin: 8px 0; }
.nav-arrow { flex: 0 0 auto; padding: 7px 12px; font-size: 13px; }
.nav-arrow:disabled { opacity: .35; }
.nav-chip { flex: 1; text-align: center; font-size: 13px; font-weight: 600; color: var(--ink); }
.hero { background: linear-gradient(135deg, #1a73e8, #4a90e2); color: #fff; border-radius: 16px;
        padding: 18px 16px; margin: 4px 0 16px; }
.hero-big { font-size: 30px; font-weight: 800; line-height: 1.1; }
.hero-total { font-size: 15px; font-weight: 400; opacity: .9; }
.hero-bar { height: 8px; background: rgba(255,255,255,.25); border-radius: 4px; overflow: hidden; margin: 10px 0 8px; }
.hero-bar i { display: block; height: 100%; background: #fff; border-radius: 4px; width: 0; transition: width .6s; }
.hero .sim { color: rgba(255,255,255,.94); }
.hero .btns .primary { background: #fff; color: var(--primary); border-color: #fff; }
.hero .btns .ghost { color: #fff; }
.book-card { background: var(--card); border: 1px solid var(--line); border-radius: 16px;
             padding: 14px; margin: 14px 0; }
.book-head { display: flex; align-items: center; gap: 8px; margin-bottom: 14px; }
.book-ico { font-size: 20px; }
.book-name { font-size: 15px; font-weight: 700; flex: 1; }
.book-name .sim { font-weight: 400; }
.book-count { font-size: 13px; font-weight: 700; color: var(--primary); background: #f2f6ff;
              border-radius: 999px; padding: 3px 10px; }
.tree-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px 6px; }
.tree-item { text-align: center; cursor: pointer; }
.tree-node { width: 54px; height: 54px; margin: 0 auto; border-radius: 50%;
             background: #eef1f4; border: 2px solid var(--line); color: #5f6368;
             display: flex; align-items: center; justify-content: center;
             font-size: 18px; font-weight: 700; transition: transform .12s, box-shadow .12s; }
.tree-item:hover .tree-node { transform: translateY(-2px); box-shadow: 0 4px 10px rgba(0,0,0,.12); }
.tree-node.done { background: #ffd54f; border-color: #ffb300; color: #7a4d00; }
.tree-node.started { background: #d3e3fd; border-color: #a8c7fa; color: var(--primary); }
.tree-node.current { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(26,115,232,.22);
                     color: var(--primary); background: #fff; }
.tree-label { font-size: 12px; color: var(--ink); margin-top: 6px; line-height: 1.3; }
.tree-en { font-size: 10px; color: #999; line-height: 1.3; }
.done-card { border-left: 4px solid #ffb300; }
.cat-block { margin: 18px 0 6px; }
.cat-head { display: flex; align-items: center; gap: 8px; font-size: 15px; font-weight: 700;
            margin: 0 0 4px; padding: 2px 0; }
.cat-count { margin-left: auto; font-size: 12px; font-weight: 600; color: var(--sub); }

/* ---------- 登录 / 报名门 ---------- */
.auth { min-height: 100vh; display: flex; align-items: center; justify-content: center;
        padding: 24px 16px; background: var(--bg); }
.auth-card { width: 100%; max-width: 400px; background: var(--card); border: 1px solid var(--line);
             border-radius: 16px; padding: 24px 20px; box-shadow: 0 2px 10px rgba(0,0,0,.06); }
.auth-brand { font-size: 24px; font-weight: 800; text-align: center; }
.auth-sub { text-align: center; color: var(--sub); font-size: 13px; margin: 4px 0 16px; }
.auth-tabs { display: flex; gap: 4px; background: #f1f3f4; border-radius: 10px; padding: 4px; margin-bottom: 16px; }
.auth-tab { flex: 1; text-align: center; padding: 9px 0; font-size: 14px; border-radius: 8px;
            cursor: pointer; color: var(--sub); font-weight: 500; }
.auth-tab.active { background: #fff; color: var(--primary); font-weight: 600; box-shadow: 0 1px 3px rgba(0,0,0,.08); }
.auth-form input { width: 100%; border: 1px solid var(--line); border-radius: 10px;
                   padding: 11px 12px; font-size: 15px; font-family: inherit; margin-top: 10px; }
.auth-form input:first-child { margin-top: 0; }
.auth-form input:focus { outline: none; border-color: var(--primary); }
.auth-btn { width: 100%; margin-top: 16px; padding: 12px; }
.auth-note { font-size: 12px; color: var(--sub); line-height: 1.6; margin: 12px 0 0; text-align: center; }
.auth-msg { margin-top: 14px; padding: 10px 12px; border-radius: 10px; font-size: 13px; line-height: 1.6; }
.auth-msg.ok { background: #eefaf1; border: 1px solid #cdeed6; color: var(--ok); }
.auth-msg.bad { background: #fce8e6; border: 1px solid #f5d9cd; color: var(--bad); }

/* 顶部用户区 */
.brand-right { display: flex; align-items: center; gap: 2px; flex: 0 0 auto; }
.user-chip { font-size: 13px; display: inline-flex; align-items: center; gap: 4px; }
.user-chip #user-name { max-width: 90px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* 课程册选择（登录后首页） */
.book-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.book-pick { background: var(--card); border: 1px solid var(--line); border-radius: 14px;
             padding: 14px; cursor: pointer; display: flex; gap: 12px; align-items: flex-start;
             transition: transform .12s, box-shadow .12s; }
.book-pick:hover { transform: translateY(-2px); box-shadow: 0 6px 16px rgba(0,0,0,.1); }
.book-pick-ico { font-size: 26px; line-height: 1; }
.book-pick-info { flex: 1; min-width: 0; }
.book-pick-name { font-size: 14px; font-weight: 700; margin-bottom: 3px; }
.book-pick-meta { font-size: 12px; color: var(--sub); margin-bottom: 8px; }
.book-pick-bar { height: 6px; background: var(--line); border-radius: 3px; overflow: hidden; }
.book-pick-bar i { display: block; height: 100%; background: var(--primary); border-radius: 3px; width: 0; transition: width .5s; }

/* 账号设置弹窗 */
.modal { position: fixed; inset: 0; background: rgba(0,0,0,.4); display: flex;
         align-items: center; justify-content: center; padding: 20px; z-index: 100; }
.modal-card { width: 100%; max-width: 380px; background: var(--card); border-radius: 16px;
              padding: 22px; box-shadow: 0 10px 40px rgba(0,0,0,.2); }
.modal-card h3 { margin: 0 0 6px; }
.modal-card input { width: 100%; border: 1px solid var(--line); border-radius: 10px;
                    padding: 11px 12px; font-size: 15px; font-family: inherit; margin: 6px 0; }
.modal-card input:focus { outline: none; border-color: var(--primary); }

/* ---------- 底部音频播放条 ---------- */
.audio-player { position: fixed; left: 0; right: 0; bottom: 0; z-index: 200;
  display: flex; align-items: center; gap: 10px; padding: 10px 14px;
  padding-bottom: calc(10px + env(safe-area-inset-bottom));
  background: #fff; border-top: 1px solid var(--line); box-shadow: 0 -2px 12px rgba(0,0,0,.08); }
.ap-btn { flex: 0 0 auto; width: 40px; height: 40px; border-radius: 50%;
  border: 1px solid var(--line); background: #fff; font-size: 15px; cursor: pointer; padding: 0; }
.ap-btn:active { background: #f1f3f4; }
.ap-track { flex: 1; position: relative; height: 40px; cursor: pointer; touch-action: none; }
.ap-fill { position: absolute; left: 0; top: 50%; transform: translateY(-50%); height: 6px;
  background: var(--primary); border-radius: 3px; width: 0; pointer-events: none; }
.ap-thumb { position: absolute; top: 50%; transform: translate(-50%, -50%); width: 16px; height: 16px;
  border-radius: 50%; background: var(--primary); box-shadow: 0 0 0 3px #fff, 0 0 0 4px var(--primary);
  pointer-events: none; left: 0; }
.ap-time { flex: 0 0 auto; font-size: 12px; color: var(--sub); font-variant-numeric: tabular-nums;
  white-space: nowrap; min-width: 74px; text-align: right; }
.ap-speed { font-size: 13px; font-weight: 700; color: var(--primary); border-color: #d7e6ff; background: #f2f6ff; }
/* 热身听句：作答后揭示的原句/翻译 */
.warm-reveal { margin-top: 10px; }