:root{--bg:#f4f6fa;--surface:#fff;--ink:#243348;--muted:#68778c;--line:#dce3ed;--blue:#2868cf;--blue-soft:#eaf2ff;--green:#297a4d;--red:#c54337}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif}.topbar{background:#fff;border-bottom:1px solid var(--line)}.topbar-inner,.app-shell{max-width:1140px;margin:auto;padding-left:max(20px,env(safe-area-inset-left));padding-right:max(20px,env(safe-area-inset-right))}.topbar-inner{min-height:82px;display:flex;align-items:center;justify-content:space-between;gap:15px}.eyebrow{font-size:11px;letter-spacing:.1em;color:var(--blue);font-weight:650;margin:0 0 7px}h1,h2,h3,p{margin:0}h1{font-size:25px;letter-spacing:-.03em}.top-hint{font-size:13px;color:var(--muted)}.app-shell{padding-top:28px;padding-bottom:45px}.mode-tabs{display:grid;grid-template-columns:1fr 1fr;gap:10px;max-width:670px;margin-bottom:22px}.mode-tabs button{display:flex;align-items:center;gap:11px;border:1px solid var(--line);border-radius:13px;background:#fff;text-align:left;padding:12px 15px;color:var(--muted);cursor:pointer}.mode-tabs button[aria-selected=true]{border-color:#82a9e8;background:var(--blue-soft);color:#244a88;box-shadow:0 0 0 2px #2868cf0c}.mode-tabs strong,.mode-tabs small{display:block}.mode-tabs strong{font-size:14px;color:var(--ink)}.mode-tabs small{font-size:11px;margin-top:3px}.tab-number{width:28px;height:28px;display:grid;place-items:center;border-radius:8px;background:#eef2f8;font-size:11px;font-weight:650}.mode-tabs button[aria-selected=true] .tab-number{background:#d7e7ff;color:var(--blue)}button:focus-visible{outline:3px solid var(--blue);outline-offset:3px}.simple-panel{background:#fff;border:1px solid var(--line);border-radius:17px;overflow:hidden}.simple-note{height:50px;padding:0 16px;display:flex;align-items:center;gap:10px;border-bottom:1px solid var(--line)}.simple-note span{font-size:11px;color:#41628d;background:#edf3fc;border-radius:5px;padding:4px 7px}.simple-note p{font-size:12px;color:var(--muted)}iframe{display:block;width:100%;height:min(780px,calc(100vh - 185px));min-height:570px;border:0}.advanced-intro{display:flex;align-items:center;justify-content:space-between;gap:22px;margin:5px 0 22px}.advanced-intro h2{font-size:27px;letter-spacing:-.035em}.advanced-intro>div:first-child>p:last-child{font-size:13px;color:var(--muted);line-height:1.75;margin-top:9px;max-width:690px}.scope-card{display:grid;grid-template-columns:auto auto;align-items:center;gap:0 7px;padding:13px 17px;min-width:125px;background:#fff;border:1px solid var(--line);border-radius:12px}.scope-card strong{font:400 31px/1 Georgia,serif;color:var(--blue);grid-row:span 2}.scope-card span{font-size:12px;font-weight:600}.scope-card small{font-size:10px;color:var(--muted);white-space:nowrap}.catalogue{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:7px;background:#fff;border:1px solid var(--line);border-radius:16px;padding:15px;margin-bottom:20px}.sound-choice{height:46px;border:1px solid #dbe2eb;border-radius:8px;background:#fff;color:var(--red);font:400 23px/1 "Times New Roman",serif;cursor:pointer}.sound-choice:hover,.sound-choice[aria-pressed=true]{border-color:var(--blue);background:var(--blue-soft)}.sound-choice.group-start{box-shadow:-5px 0 0 -4px #b8c9e2}.advanced-layout{display:grid;grid-template-columns:minmax(0,1fr) 235px;gap:18px}.lesson,.learning-route{background:var(--surface);border:1px solid var(--line);border-radius:16px}.lesson{min-height:360px;padding:26px}.lesson-head{display:grid;grid-template-columns:auto 1fr;gap:18px;align-items:center;padding-bottom:21px;border-bottom:1px solid #e7ebf1}.lesson-ipa{font:400 76px/1 "Times New Roman",serif;color:var(--red);min-width:95px;text-align:center}.lesson-kicker{font-size:12px;color:var(--blue);font-weight:650}.lesson-head h2{font-size:22px;margin-top:5px}.lesson-subtitle{font-size:13px;color:var(--muted);line-height:1.7;margin-top:7px}.listen{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:40px;border:0;border-radius:9px;background:var(--blue);color:white;font-size:13px;padding:0 14px;margin-top:13px;cursor:pointer}.listen[aria-pressed=true]{background:#194d9f}.lesson-body{display:grid;grid-template-columns:1.05fr .95fr;gap:22px;margin-top:22px}.lesson-body h3{font-size:14px;margin-bottom:9px}.lesson-body p{font-size:13px;color:#53647b;line-height:1.8}.cue-list{display:grid;gap:10px;margin-top:12px}.cue{padding:11px 12px;background:#f7f9fc;border-radius:8px}.cue strong{display:block;font-size:12px}.cue span{display:block;color:var(--muted);font-size:12px;line-height:1.6;margin-top:3px}.word-list{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}.word{min-height:77px;border:1px solid #e0e6ee;border-radius:9px;padding:10px}.word strong{display:block;font:400 20px/1.3 Georgia,serif;color:#2d405b}.word em{display:block;font:400 14px/1.4 "Times New Roman",serif;color:#5274a5;margin-top:2px}.word span{display:block;color:var(--muted);font-size:11px;margin-top:5px}.lesson-warning{display:flex;gap:8px;background:#fff8e9;border:1px solid #f0d59c;border-radius:9px;padding:10px 12px;font-size:12px;line-height:1.7;color:#735a29;margin-top:20px}.learning-route{padding:22px}.learning-route ol{list-style:none;margin:17px 0 20px;padding:0;display:grid;gap:15px}.learning-route li{display:flex;gap:9px;color:#596a80;font-size:12px;line-height:1.6}.learning-route li span{width:20px;height:20px;display:grid;place-items:center;flex-shrink:0;background:#edf3fc;color:#3866a1;border-radius:50%;font-size:11px}.accent-note{border-top:1px solid #e5eaf1;padding-top:15px;color:#7c899a;font-size:11px;line-height:1.75}.source-note{background:#fff;border:1px solid var(--line);border-radius:11px;margin-top:16px;color:#66768b;font-size:12px;line-height:1.8}.source-note summary{cursor:pointer;padding:13px 15px}.source-note div{padding:0 15px 14px}.source-note a{color:#3a67a8}.source-note ul{margin:7px 0;padding-left:18px}
@media(max-width:900px){.catalogue{grid-template-columns:repeat(8,minmax(0,1fr))}.advanced-layout{grid-template-columns:1fr}.learning-route{display:grid;grid-template-columns:160px 1fr;gap:18px}.learning-route .eyebrow{margin:3px 0}.learning-route ol{margin:0;grid-template-columns:repeat(3,1fr);gap:8px}.accent-note{grid-column:1/-1;margin:0;padding-top:14px}.lesson-body{grid-template-columns:1fr}.word-list{max-width:590px}}
@media(max-width:600px){.topbar-inner{min-height:70px}.top-hint{display:none}h1{font-size:20px}.app-shell{padding-top:17px}.mode-tabs{gap:8px;margin-bottom:16px}.mode-tabs button{padding:10px;gap:8px}.mode-tabs small{display:none}.simple-note{height:auto;min-height:45px}.simple-note p{line-height:1.5}iframe{height:calc(100svh - 150px);min-height:520px}.advanced-intro{display:block;margin-top:4px}.advanced-intro h2{font-size:23px}.scope-card{display:inline-grid;margin-top:15px}.catalogue{grid-template-columns:repeat(4,minmax(0,1fr));padding:11px;gap:7px}.sound-choice{height:48px;font-size:24px}.advanced-layout{gap:12px}.lesson{padding:20px 16px}.lesson-head{grid-template-columns:72px 1fr;gap:11px}.lesson-ipa{font-size:58px;min-width:0}.lesson-head h2{font-size:18px}.lesson-subtitle{font-size:12px}.lesson-body{gap:17px}.word-list{grid-template-columns:repeat(3,minmax(0,1fr));gap:6px}.word{min-height:94px;padding:9px}.word strong{font-size:18px}.word em{font-size:13px}.word:last-child{grid-column:auto}.learning-route{display:block;padding:18px}.learning-route ol{margin-top:15px}.accent-note{margin-top:16px}.source-note{font-size:11px}.scope-card{padding:10px 13px}.advanced-intro>div:first-child>p:last-child{font-size:12px}}

/* 高级版：复用的教学卡片与抽象示意，不包含解剖图。 */
html,body{overflow-x:hidden}.advanced-layout{display:block}.lesson{background:transparent;border:0;padding:0;min-height:0}.lesson-overview{display:grid;grid-template-columns:minmax(245px,.75fr) minmax(0,1.25fr);gap:20px}.sound-card,.guide-card,.teaching-visual,.words-card{border:1px solid var(--line);border-radius:20px;background:var(--surface)}.sound-card{padding:21px 23px 20px;text-align:center;display:flex;flex-direction:column;align-items:center;background:linear-gradient(145deg,#e9f2ff,#f8fbff);border-color:#c9dbf6}.sound-card-top{width:100%;display:flex;align-items:center;justify-content:space-between;gap:8px;color:#5b7394;font-size:11px}.category-pill{border:1px solid #cbdcf5;border-radius:6px;padding:4px 7px;background:#f8fbff;color:#42699e;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:74%}.big-ipa{font:400 88px/1.1 "Times New Roman",serif;color:var(--red);margin:17px 0 5px;letter-spacing:-.04em}.sound-name{font-size:17px;font-weight:700}.sound-card>p:not(.audio-caption){font-size:13px;line-height:1.7;color:var(--muted);margin-top:8px;max-width:300px}.primary-listen{display:flex;align-items:center;justify-content:center;gap:8px;width:100%;min-height:48px;padding:0 13px;margin-top:20px;border:0;border-radius:11px;background:var(--blue);color:#fff;font-size:14px;box-shadow:0 4px 10px #2867cd19}.primary-listen[aria-pressed=true]{background:#174d9f}.audio-caption{font-size:10px;color:var(--muted);margin-top:9px}.guide-card{padding:24px}.guide-heading,.words-heading{display:flex;align-items:start;justify-content:space-between;gap:16px}.guide-heading h2{font-size:22px;letter-spacing:-.035em;line-height:1.3}.guide-count{display:grid;place-items:center;min-width:45px;height:28px;border-radius:20px;background:#eef4fe;color:#466c9f;font-size:11px;font-weight:700}.step-list{list-style:none;padding:0;margin:21px 0 17px;display:grid;gap:13px}.step-list li{display:flex;gap:12px}.step-number{display:grid;place-items:center;flex:0 0 auto;width:25px;height:25px;border-radius:50%;background:#e8f1ff;color:var(--blue);font-size:11px;font-weight:700}.step-list strong{font-size:13px}.step-list p{font-size:13px;color:var(--muted);line-height:1.65;margin-top:3px}.lesson-warning{display:flex;gap:10px;padding:11px 12px;background:#fff8e9;border:1px solid #efcf8b;border-radius:10px;color:#725c2d}.lesson-warning>span{display:grid;place-items:center;width:18px;height:18px;flex:0 0 auto;border-radius:50%;background:#efd399;color:#6f592d;font:700 12px/1 Georgia,serif}.lesson-warning strong{font-size:12px}.lesson-warning p,.safe-note{font-size:12px;line-height:1.6;color:#725c2d;margin-top:2px}.safe-note{border-top:1px solid var(--line);padding-top:14px;color:var(--muted)}.detail-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:20px;margin-top:20px}.teaching-visual,.words-card{min-width:0;min-height:279px;padding:20px 22px}.teaching-visual{display:flex;flex-direction:column;justify-content:space-between;overflow:hidden}.teaching-visual figcaption{display:grid;gap:5px;font-size:11px;line-height:1.5;color:var(--muted)}.visual-label{font-size:13px;font-weight:700;color:var(--ink)}.teaching-visual svg{display:block;width:100%;max-width:340px;height:auto;margin:9px auto 0;overflow:visible;font-family:-apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif;font-size:11px;fill:var(--muted)}.v-grid{stroke:#d8e2ef;stroke-width:1;fill:none}.v-point,.v-start{fill:#c44338}.v-end{fill:#2867cd}.v-wave{stroke:#c44338;stroke-width:2;fill:none}.v-arrow,.c-flow{stroke:#2867cd;stroke-width:3;fill:none}.v-arrow-head,.c-flow-head{stroke:#2867cd;stroke-width:3;fill:none}.c-block,.c-block-alt{fill:#eaf2ff;stroke:#bcd2f4;stroke-width:1.5}.c-block-alt{fill:#f7f9fc;stroke:#dbe4f0}.c-voice{fill:#c44338}.c-lines{stroke:#fff;stroke-width:1.5;fill:none}.cluster-one{fill:#fff0ed;stroke:#efb7af;stroke-width:1.5}.cluster-two{fill:#eaf2ff;stroke:#bcd2f4;stroke-width:1.5}.cluster-text{font:400 25px/1 "Times New Roman",serif;fill:var(--ink)}.words-heading{padding-bottom:16px;border-bottom:1px solid #e7ecf3}.words-heading h2{font-size:20px}.words-heading>p{margin-top:4px;color:var(--muted);font-size:11px;line-height:1.5;text-align:right}.word-list{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin-top:16px}.word{min-width:0;min-height:102px;border:1px solid #e0e6ee;border-radius:10px;padding:11px}.word strong{overflow-wrap:anywhere}.word em{overflow-wrap:anywhere}.learning-route{grid-template-columns:165px 1fr;margin-top:20px}.learning-route ol{grid-template-columns:repeat(3,minmax(0,1fr))}.accent-note{grid-column:1/-1}
@media(max-width:900px){.lesson-overview{grid-template-columns:280px minmax(0,1fr)}.detail-grid{grid-template-columns:1fr}.teaching-visual,.words-card{min-height:250px}}
@media(max-width:600px){.lesson-overview{grid-template-columns:1fr;gap:12px}.sound-card,.guide-card,.teaching-visual,.words-card{border-radius:16px}.sound-card{padding:18px}.big-ipa{font-size:76px;margin-top:13px}.guide-card{padding:20px 17px}.guide-heading h2{font-size:19px}.detail-grid{gap:12px;margin-top:12px}.teaching-visual,.words-card{padding:18px 16px;min-height:238px}.word-list{grid-template-columns:repeat(3,minmax(0,1fr));gap:6px}.word{min-height:94px;padding:9px}.word strong{font-size:18px}.word em{font-size:13px}.word:last-child{grid-column:auto}.learning-route{display:block;margin-top:12px}.learning-route ol{grid-template-columns:1fr}.accent-note{margin-top:16px}}
/* 标签跟随当前音标的相对位置，仍只表示教学位置。 */
.v-symbol{font:400 17px/1 "Times New Roman",serif;fill:var(--blue)}
.practice-card{display:flex;align-items:center;justify-content:space-between;gap:25px;margin-top:20px;padding:22px 24px;border:1px solid #d9e7e0;border-radius:16px;background:#f0f7f3}.practice-card h2{font-size:17px;color:#355748;margin-top:3px}.practice-card h2 span{font-family:Georgia,"Times New Roman",serif}.practice-card p:last-child{font-size:12px;color:#63796d;line-height:1.7;margin-top:6px}.self-check{list-style:none;margin:0;padding:0;display:grid;gap:8px;min-width:285px}.self-check li{display:flex;align-items:flex-start;gap:8px;color:#527361;font-size:12px;line-height:1.5}.self-check input{width:16px;height:16px;margin:1px 0 0;accent-color:#448461;flex:0 0 auto}.self-check label{cursor:pointer}
@media(max-width:600px){.practice-card{display:block;padding:19px 18px;margin-top:12px}.practice-card h2{font-size:16px}.self-check{min-width:0;margin-top:16px;gap:10px}.self-check li{font-size:12px}}

/* 高级版沿用简易版的双栏音标表；教学内容在弹出的卡片中查看。 */
.advanced-board{display:grid;grid-template-columns:1fr 1.04fr;gap:18px;align-items:start}
.advanced-panel{background:#fff;border:1px solid var(--line);border-radius:17px;padding:20px}
.advanced-section-title{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}
.advanced-section-title h2{margin:0;font-size:21px;letter-spacing:.08em}
.advanced-section-title>span{font-size:12px;color:var(--muted)}
.advanced-panel .advanced-section-title:not(:first-child){margin-top:25px;padding-top:23px;border-top:1px solid var(--line)}
.sound-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px}
.sound-grid .sound-choice{height:65px;font-size:30px}
.sound-grid .sound-choice[aria-pressed=true]{border-color:#82a9e8;background:var(--blue-soft)}

.lesson-dialog{width:min(900px,calc(100vw - 28px));max-height:calc(100svh - 28px);margin:auto;padding:0;border:0;border-radius:20px;background:transparent;color:var(--ink);overflow:visible}
.lesson-dialog::backdrop{background:rgb(23 43 71 / .5);backdrop-filter:blur(3px)}
.lesson-dialog-inner{position:relative;max-height:calc(100svh - 28px);overflow:auto;padding:20px;background:var(--bg);border:1px solid #cdd9e9;border-radius:20px;box-shadow:0 20px 55px #172b4752}
.dialog-close{position:sticky;top:0;z-index:4;float:right;width:36px;height:36px;margin:-8px -8px 0 12px;border:1px solid var(--line);border-radius:50%;background:#fff;color:var(--ink);font-size:26px;line-height:1;cursor:pointer;box-shadow:0 2px 7px #263e5b14}
.lesson-dialog .lesson{max-width:820px;margin:0 auto}

@media(max-width:760px){
  .advanced-board{grid-template-columns:1fr;gap:14px}
  .advanced-panel{padding:17px 14px}
}
@media(max-width:600px){
  .advanced-intro{margin-bottom:17px}
  .advanced-intro h2{font-size:22px}
  .advanced-panel{border-radius:15px;padding:16px 12px}
  .advanced-section-title{margin-bottom:12px}
  .advanced-section-title h2{font-size:19px}
  .advanced-panel .advanced-section-title:not(:first-child){margin-top:21px;padding-top:20px}
  .sound-grid{gap:8px}
  .sound-grid .sound-choice{height:58px;font-size:27px}
  .lesson-dialog{width:calc(100vw - 16px);max-height:calc(100svh - 16px);border-radius:16px}
  .lesson-dialog-inner{max-height:calc(100svh - 16px);padding:12px;border-radius:16px}
  .dialog-close{width:34px;height:34px;margin:-2px -2px 0 8px}
}

/* 关闭键脱离正文排版，固定在弹窗容器右上角。 */
.lesson-dialog-inner{overflow:hidden;padding:0}
.lesson-dialog-scroll{max-height:calc(100svh - 28px);overflow:auto;padding:62px 20px 20px}
.dialog-close{position:absolute;top:14px;right:14px;float:none;margin:0}
@media(max-width:600px){
  .lesson-dialog-scroll{max-height:calc(100svh - 16px);padding:52px 12px 12px}
  .dialog-close{top:10px;right:10px;margin:0}
}

/* 详细讲解页处于原项目容器中，不再重复占用左右页面边距。 */
.explain-shell { max-width: none; padding-left: 0; padding-right: 0; }

/* 手机端讲解卡片直接覆盖详细讲解区域，避免 iframe 内出现二次遮罩框。 */
@media (max-width: 600px) {
  .lesson-dialog { width: 100vw; height: 100svh; max-width: none; max-height: none; margin: 0; border: 0; border-radius: 0; background: #f4f6fa; }
  .lesson-dialog::backdrop { background: transparent; backdrop-filter: none; }
  .lesson-dialog-inner { width: 100%; height: 100%; max-height: none; border: 0; border-radius: 0; box-shadow: none; background: #f4f6fa; }
  .lesson-dialog-scroll { height: 100%; max-height: none; padding: 54px 12px max(18px, env(safe-area-inset-bottom)); }
  .dialog-close { top: 10px; right: 10px; }
}