:root{color-scheme:light;--ink:#203536;--muted:#61706e;--gold:#d8b276;--dark:#142326;--paper:#f6f5f0;--line:#dadfd9;--accent:#356a63;font-family:"Microsoft YaHei","PingFang SC",system-ui,sans-serif;font-size:16px}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink)}button{font:inherit;cursor:pointer}button:disabled{cursor:default;opacity:.32}button:focus-visible,#gallery:focus-visible{outline:3px solid #c48a3d;outline-offset:4px}button{touch-action:manipulation}h1,h2,h3,p{margin:0}.masthead{display:flex;gap:17px;align-items:center;padding:24px 36px 22px;border-bottom:1px solid var(--line)}.brandmark{width:35px;height:38px;display:flex;align-items:flex-end;gap:5px}.brandmark i{display:block;background:var(--accent);width:7px;height:18px}.brandmark i:nth-child(2){height:28px}.brandmark i:nth-child(3){height:38px}.eyebrow{font-size:.75rem;letter-spacing:.12em;color:var(--muted);line-height:1.6}.heading h1{font-size:clamp(1.1rem,1.7vw,1.65rem);font-weight:600;letter-spacing:.025em;margin-top:5px}.header-label{margin-left:auto;border-left:1px solid #c9d2cc;padding-left:22px;font-size:.88rem;white-space:nowrap}.header-label span{display:block;font-size:.75rem;color:var(--muted);margin-top:6px}.experience{display:grid;grid-template-columns:minmax(0,1.3fr) minmax(390px,1fr);min-height:660px;height:calc(100dvh - 237px);max-height:940px;margin:20px 28px 0;gap:0;border:1px solid #cbd3cd;border-radius:8px;overflow:hidden}.visual{position:relative;min-height:560px;background:var(--dark);overflow:hidden;color:#f4f0e6}#gallery{position:absolute;inset:0;cursor:grab;touch-action:none}#gallery:active{cursor:grabbing}#gallery canvas{display:block;width:100%;height:100%}.scene-heading{position:absolute;top:28px;left:28px;right:98px;display:flex;gap:17px;align-items:center;pointer-events:none}.scene-heading>span{color:var(--gold);font-family:Georgia,serif;font-size:3.25rem;line-height:1}.scene-heading .eyebrow{color:#b1bdb5;font-size:.75rem;letter-spacing:.17em}.scene-heading h2{font-weight:500;font-size:clamp(1rem,1.3vw,1.4rem);line-height:1.6}.scene-tools{position:absolute;right:18px;top:25px;display:flex;gap:7px}.icon-button{border:1px solid #ffffff2b;background:#14232699;color:#e7e6d9;border-radius:5px;width:34px;height:36px;font-size:1.25rem}.icon-button:hover{background:#34534e}.scene-caption{position:absolute;bottom:126px;left:28px;right:28px;text-align:center;pointer-events:none}.scene-caption p{font-size:1rem;letter-spacing:.07em;text-shadow:0 2px 6px #000}.scene-caption span{font-size:.75rem;display:block;color:#b8c4bc;margin-top:7px}.drag-hint{position:absolute;bottom:89px;left:0;right:0;text-align:center;font-size:.8rem;color:#a8bab4;pointer-events:none;transition:opacity .5s}.drag-hint span{display:inline-block;margin-right:4px;font-size:1.25rem;color:var(--gold)}.scene-nav{position:absolute;bottom:0;left:0;right:0;border-top:1px solid #ffffff1f;background:#112022da;backdrop-filter:blur(10px);display:flex;justify-content:space-between;align-items:center;padding:17px 26px;font-size:.875rem}.scene-nav button{border:0;background:transparent;color:#f1ebdd;padding:6px 0}.scene-nav button:not(:disabled):hover{color:var(--gold)}.scene-nav>span{font:1rem Georgia,serif;letter-spacing:.12em;color:var(--gold)}.scene-nav button span{margin:0 8px}#fallback{position:absolute;inset:105px 22px 165px;display:flex;flex-direction:column;justify-content:center}#fallback[hidden]{display:none}#fallback img{width:100%;max-height:100%;object-fit:contain;border:7px solid #584e3a}#fallback p{font-size:.8rem;margin-top:12px;color:#b9c5bc}.lesson{overflow-y:auto;background:#fafaf6;scrollbar-width:thin;scrollbar-color:#b8c5bb transparent}.lesson-topline{display:flex;justify-content:space-between;gap:10px;background:#edf0e8;padding:14px 25px;font-size:.8rem;border-bottom:1px solid var(--line);color:#435b54}.lesson-topline>span:last-child{white-space:nowrap}#lesson-body{padding:24px 28px 25px}.section-kicker{font-size:.75rem;color:#637969;letter-spacing:.06em;font-weight:600;margin-bottom:11px}.cause-block h2{font-size:1.27rem;line-height:1.6;font-weight:600}.cause-block>p:not(.section-kicker){font-size:.94rem;line-height:1.85;color:#4b5e56;margin-top:9px}.cause-chain{display:flex;align-items:center;flex-wrap:wrap;gap:5px;margin-top:14px}.cause-chain span{font-size:.8rem;line-height:1.6;background:#e9eee4;border:1px solid #d8e0d2;padding:5px 8px;border-radius:3px}.cause-chain i{font-style:normal;font-size:.8rem;color:#879587}.contrast-block{margin-top:25px}.contrast{display:grid;grid-template-columns:1fr 1fr;gap:0;border-top:1px solid #ced8cc;border-bottom:1px solid #ced8cc}.contrast>div{padding:16px 15px}.contrast>.before{padding-left:0}.contrast>.after{background:#edf1e9;border-left:1px solid #d4ddd0}.era-tag{font-size:.75rem;color:#6c7b6b;display:block;margin-bottom:5px}.contrast h3{font-size:1.06rem;font-weight:600;margin-bottom:13px}.contrast dl{margin:0}.contrast dt{font-size:.75rem;color:#627461;margin-top:11px}.contrast dd{font-size:.92rem;line-height:1.7;margin:3px 0 0}.quiz{margin-top:24px}.quiz-title{display:flex;justify-content:space-between;align-items:center}.quiz-title button{border:0;background:transparent;font-size:.8rem;color:#436d5b;text-decoration:underline;padding:0 0 11px}.quiz h3{font-size:1rem;font-weight:500;line-height:1.7;margin-bottom:12px}.quiz-options{display:grid;gap:8px}.quiz-options button{display:flex;align-items:center;gap:10px;padding:10px 12px;border:1px solid #ccd5c7;border-radius:4px;text-align:left;background:#fff;font-size:.9rem;color:#334932;line-height:1.6;transition:background .15s,border .15s}.quiz-options button:hover{background:#eff3e9;border-color:#809a77}.quiz-options button .option-key{display:grid;place-items:center;flex:0 0 25px;height:25px;border:1px solid #c7d4c1;border-radius:50%;font: .85rem Georgia,serif}.quiz-options button.correct{background:#e5eee1;border-color:#638b57}.quiz-options button.wrong{background:#f7ebe2;border-color:#bc7953}.quiz-options button.correct .option-key{background:#4e7544;color:#fff;border-color:#4e7544}.quiz-options button.wrong .option-key{background:#af714c;color:#fff;border-color:#af714c}.feedback{margin-top:11px;padding:10px 12px;font-size:.86rem;line-height:1.8;border-left:3px solid #6b8958;background:#edf1e8;color:#3b5131}.feedback.wrong{border-color:#b9825b;background:#f8eee7;color:#72523c}.journey{margin:18px 28px 15px}.stops{display:grid;grid-template-columns:repeat(3,1fr);gap:15px}.stops button{position:relative;display:flex;gap:13px;align-items:center;text-align:left;background:transparent;border:1px solid #cdd5cd;border-radius:5px;color:#4c625a;padding:14px 18px;min-width:0}.stops button[aria-current]{background:#203b36;border-color:#203b36;color:#f0ecd9}.stops button:hover{border-color:#59826d}.stop-number{font:1.5rem Georgia,serif;color:#7d8e7d}.stops button[aria-current] .stop-number{color:#d9ba81}.stops b{font-size:.88rem;font-weight:500;line-height:1.5}.stops small{display:block;font-size:.75rem;margin-top:4px;color:#7c8a7b;line-height:1.5}.stops button[aria-current] small{color:#becabb}.completion{margin-left:auto;color:#a0b68c;font-size:1rem}.footnote{display:flex;justify-content:space-between;gap:15px;font-size:.75rem;color:#7c877c;margin:11px 2px 0;line-height:1.6}noscript{display:block;background:#f9d6a9;padding:30px}.visual::after{content:"";position:absolute;inset:0;pointer-events:none;box-shadow:inset 0 0 90px #0003}body:fullscreen{overflow:auto}@media(min-width:1700px){.experience{grid-template-columns:1.5fr 1fr}#lesson-body{padding:30px 36px}.cause-block h2{font-size:1.4rem}.contrast dd{font-size:1rem}.quiz-options button{font-size:1rem;padding:12px}.scene-heading{top:34px;left:34px}.scene-heading h2{font-size:1.6rem}}@media(max-width:1050px){.masthead{padding:20px 22px}.header-label{display:none}.experience{grid-template-columns:minmax(0,1fr) minmax(350px,1fr);margin:16px 18px 0}#lesson-body{padding:21px}.scene-heading{left:20px;right:70px;top:22px;gap:12px}.scene-heading>span{font-size:2.4rem}.scene-heading h2{font-size:1rem}.scene-tools{top:82px;right:17px}.journey{margin:15px 18px}.stops{gap:9px}.stops button{padding:11px;gap:8px}.stops b{font-size:.8rem}.stops small{font-size:.75rem}.lesson-topline{padding:12px 17px;font-size:.75rem}}@media(max-width:780px){.masthead{padding:17px 16px;gap:12px}.brandmark{transform:scale(.78);width:28px}.heading .eyebrow{font-size:.75rem;letter-spacing:.03em}.heading h1{font-size:1.1rem;line-height:1.55}.experience{display:flex;flex-direction:column;height:auto;max-height:none;min-height:0;margin:12px 12px 0}.visual{min-height:450px;height:52dvh;max-height:580px}.scene-heading h2{font-size:1.1rem}.scene-tools{top:22px}.scene-heading{right:92px}.lesson{overflow:visible}.lesson-topline{padding:14px 20px}.lesson-topline>span{font-size:.8rem}#lesson-body{padding:22px}.cause-block h2{font-size:1.25rem}.cause-block>p:not(.section-kicker){font-size:1rem}.contrast dd{font-size:1rem}.quiz-options button{font-size:1rem;padding:12px}.journey{margin:14px 12px}.stops{gap:7px}.stops button{flex-direction:column;align-items:flex-start;gap:7px;padding:11px 9px}.stops b{font-size:.78rem;line-height:1.65}.stops small{display:none}.stop-number{font-size:1.1rem}.completion{position:absolute;right:8px;top:8px}.footnote{flex-direction:column;gap:2px;font-size:.75rem}.scene-caption{bottom:120px}.drag-hint{bottom:83px}.scene-nav{padding:14px 18px}}@media(max-width:380px){.scene-heading{top:18px;gap:8px;left:15px}.scene-heading h2{font-size:.93rem}.scene-heading>span{font-size:2rem}.scene-tools{top:76px}.visual{min-height:410px}.contrast>div{padding:12px}.contrast>.before{padding-right:10px}#lesson-body{padding:18px}}@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
/* Narrated guide: controls stay visible while the lesson follows the voice. */
.narration{position:sticky;top:0;z-index:3;background:#eef2e8;border:1px solid #c5d2bd;border-radius:6px;padding:13px 14px;margin-bottom:23px;box-shadow:0 5px 14px #182d2110}.narration-controls{display:flex;align-items:center;flex-wrap:wrap;gap:8px}.narration-controls button{padding:7px 10px;font-size:.84rem;border-radius:4px;border:1px solid #90a482;background:#fff;color:#355336;min-height:36px}.narration-controls button:first-child{background:#294f41;color:#fff;border-color:#294f41}.narration-controls button:hover{filter:brightness(1.08)}#narration-status{font-size:.75rem;color:#52684d;margin-left:auto;line-height:1.5}#narration-caption{font-size:.87rem;line-height:1.8;margin-top:9px;color:#33482f}.narration-focus{outline:2px solid #b98539!important;outline-offset:5px;background-color:#eedca442!important;border-radius:3px;transition:background-color .2s}.scene-caption p.narration-focus{display:inline-block;padding:5px 12px;background:#142326df!important;color:#f8ddb2}.cause-chain.narration-focus span{background:#eee2ba;border-color:#c6a768}@media(max-width:780px){.narration{top:0;padding:12px;margin-bottom:23px}#narration-status{margin-left:0;width:100%}#narration-caption{font-size:.9rem}.narration-controls button{min-height:40px}}