@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+JP:wght@400;500&display=swap');
:root{--ink:#26352f;--paper:#f5f1e7;--line:#75847144;--muted:#6a786c}*{box-sizing:border-box}html,body{width:100%;height:100%;margin:0;overflow:hidden}body{font-family:-apple-system,BlinkMacSystemFont,'Helvetica Neue','Hiragino Kaku Gothic ProN',sans-serif;background:#24342e;color:var(--ink)}button,input{font:inherit}button,a,input{touch-action:manipulation}button{cursor:pointer;border:0;background:none;color:inherit}button:focus-visible,a:focus-visible,input:focus-visible{outline:2px solid #aa7a42;outline-offset:4px}button:hover{color:#8c6237}button:disabled{cursor:default;opacity:.45}a{color:inherit;text-underline-offset:4px}[hidden]{display:none!important}#viewport{position:absolute;inset:0;right:0}#scene{display:block;width:100%;height:100%;touch-action:none}body.panel-open #viewport{right:410px}#view-fade{position:absolute;inset:0;background:#23382c;opacity:0;pointer-events:none;transition:opacity .18s}#view-fade.active{opacity:1}header{position:absolute;left:32px;right:32px;top:25px;display:flex;justify-content:space-between;align-items:center;pointer-events:none;color:#f9f6ec;text-shadow:0 1px 9px #102015aa;z-index:4}header>*{pointer-events:auto}.brand{display:flex;align-items:center;gap:14px;text-decoration:none}.brand b{letter-spacing:.25em;font-weight:500;font-size:22px}.brand span{font-family:serif;font-size:11px;letter-spacing:.3em}.header-right{display:flex;align-items:center;gap:12px}.header-right button{min-width:38px;min-height:38px;font-size:12px;background:#1f302b77;border:1px solid #ffffff28;border-radius:30px;padding:8px 13px;text-shadow:none;color:#fff}.xync{width:72px;height:25px;object-fit:contain;margin-left:10px}.eyebrow{font-size:10px;letter-spacing:.19em;font-weight:600;line-height:1.7;text-transform:uppercase}h1,h2{font-family:'Noto Serif JP','Hiragino Mincho ProN',serif;font-weight:400}h1{font-size:clamp(40px,5vw,74px);line-height:1.4;letter-spacing:.07em;margin:18px 0 25px}h2{font-size:28px;line-height:1.5;margin:18px 0}h3{font-size:17px;line-height:1.6}p{font-size:15px;line-height:2;letter-spacing:.025em}small{font-size:11px;line-height:1.9;display:block}.muted{color:var(--muted);font-size:13px}.primary{display:block;width:100%;text-align:left;background:var(--ink);color:var(--paper);padding:18px 22px;line-height:1.5;font-size:14px;margin:20px 0 14px;transition:background .2s}.primary:hover{background:#4b634a;color:#fff}#intro{position:absolute;left:5vw;top:50%;transform:translateY(-48%);width:370px;padding:28px 30px;background:linear-gradient(100deg,#f7f4e9ef,#f7f4e9cc);backdrop-filter:blur(14px);border-top:1px solid #fffc;border-bottom:1px solid #fffc;z-index:3}#intro>p:not(.eyebrow){font-size:14px;line-height:2.2}#intro small{color:#5b695e}#scene-note{position:absolute;left:32px;bottom:112px;color:#fff;text-shadow:0 1px 9px #12352c}#scene-note p{font-size:12px;line-height:1.6;margin:5px 0;max-width:420px}#navigation{position:absolute;bottom:47px;left:50%;transform:translateX(-50%);display:flex;gap:18px;align-items:center;background:#f8f6edee;backdrop-filter:blur(16px);padding:7px 14px;border:1px solid #ffffff88;box-shadow:0 8px 28px #102b2925;border-radius:3px;z-index:3;white-space:nowrap}.places,.tools{display:flex;gap:4px}.tools{border-left:1px solid var(--line);padding-left:14px}#navigation button{font-size:12px;padding:11px 13px;border-radius:2px}#navigation .active{background:#dbe2d1;color:#2b4433}#clock{position:absolute;right:32px;bottom:118px;display:flex;align-items:center;gap:10px;color:#fff;text-shadow:0 1px 9px #15251d;font-size:13px;font-variant-numeric:tabular-nums}#clock i{width:5px;height:5px;border-radius:50%;background:#dbd6af;box-shadow:0 0 10px #fff}#clock button{background:#122e265e;color:#fff;border:1px solid #ffffff55;border-radius:50%;width:30px;height:30px}body.panel-open header{right:438px}body.panel-open #clock{right:440px}body.panel-open #navigation{left:calc((100% - 410px)/2)}#panel{position:absolute;right:0;top:0;bottom:0;width:410px;background:#f5f1e7fa;z-index:5;overflow:auto;padding:30px 30px 50px;box-shadow:-14px 0 40px #17291f18;scrollbar-width:thin}.panel-head{display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);padding-bottom:18px}.panel-head button{font-size:26px;width:36px;height:36px}#panel-body{padding-top:6px}#panel-body a{font-size:11px;line-height:1.8}#panel-body fieldset{padding:18px 0 8px;border:0;border-top:1px solid var(--line);margin:24px 0 0}legend{font-size:13px;font-weight:600;float:left;width:100%;margin:4px 0 12px}output{float:right;color:var(--muted);font-variant-numeric:tabular-nums}input[type=range]{width:100%;accent-color:#526d4b;margin:12px 0;height:22px;cursor:pointer}.options{display:flex;flex-wrap:wrap;gap:6px;margin:12px 0}.options button,.secondary{border:1px solid var(--line);font-size:12px;padding:12px 14px}.options .active{background:#dee6d4}.topic-button{width:100%;text-align:left;border-bottom:1px solid var(--line);padding:20px 0;display:flex;justify-content:space-between;align-items:center;font-family:'Noto Serif JP',serif;font-size:21px}.topic-button span{font:10px sans-serif;letter-spacing:.08em;color:var(--muted)}.step{padding:13px 0;border-bottom:1px solid var(--line);display:flex;gap:12px;align-items:center}.step i{font-style:normal;font-size:11px;border:1px solid var(--line);border-radius:50%;min-width:24px;height:24px;display:grid;place-items:center}.step.done i{background:#4e6a4a;color:#fff}.step b{font-size:13px}.step small{color:var(--muted)}.completion{padding:15px;background:#e3ead9;border-left:2px solid #6a855a;margin:20px 0;font-size:14px;line-height:1.8}.mini-help{background:#e9e7dc;padding:15px;font-size:13px;line-height:1.8}#mini-return{position:absolute;left:32px;bottom:70px;padding:14px 20px;background:#f5f1e7ee;font-size:13px;z-index:3}#hover-label{position:absolute;pointer-events:none;background:#f6f3e9f2;padding:9px 14px;border-left:2px solid #7f9764;color:#223d2d;font-size:12px;white-space:nowrap;z-index:2;box-shadow:0 4px 18px #11271822}footer{position:absolute;left:32px;right:32px;bottom:16px;display:flex;align-items:center;justify-content:space-between;color:#eee9dc;font-size:9px;letter-spacing:.12em;text-shadow:0 1px 8px #15241c;z-index:3}footer button{font-size:10px;letter-spacing:.04em;padding:7px 0}body.panel-open footer{right:440px}#restore-ui{position:absolute;bottom:20px;right:24px;padding:12px 20px;background:#f5f1e7b8;color:var(--ink);font-size:11px;z-index:6}.hidden-ui header,.hidden-ui #navigation,.hidden-ui #scene-note,.hidden-ui #clock,.hidden-ui footer{display:none}#toast{position:absolute;bottom:125px;left:50%;transform:translate(-50%,10px);background:#253f32eb;color:#fff;padding:13px 22px;opacity:0;pointer-events:none;font-size:13px;max-width:90vw;z-index:10;transition:.25s;line-height:1.7}#toast.show{opacity:1;transform:translate(-50%,0)}#loading{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;flex-direction:column;background:#ebe8dc;z-index:30;transition:opacity .6s}#loading span{font-size:24px;letter-spacing:.45em}#loading p{font-size:12px;color:var(--muted)}#loading i{width:70px;height:1px;background:#587353;animation:pulse 1.8s infinite}@keyframes pulse{50%{opacity:.2;transform:scaleX(.4)}}dialog{width:min(650px,90vw);max-height:82vh;overflow:auto;background:#f5f1e7;border:0;padding:45px;color:var(--ink);box-shadow:0 24px 100px #0005}dialog::backdrop{background:#10221899;backdrop-filter:blur(6px)}#dialog-close{float:right;font-size:25px}dialog li{font-size:12px;line-height:1.9;margin-bottom:12px}dialog p{font-size:14px}body.mini-mode #clock,body.mini-mode #navigation,body.mini-mode #scene-note{display:none}
@media(max-width:1050px){#panel{width:360px;padding:22px}body.panel-open #viewport{right:360px}body.panel-open header{right:382px}body.panel-open #navigation{left:calc((100% - 360px)/2);gap:4px;padding:6px}.tools{padding-left:7px}body.panel-open #navigation button{padding:9px 8px}body.panel-open footer,body.panel-open #clock{right:382px}.xync{display:none}}
@media(max-width:760px){header{left:20px;right:20px;top:18px}.brand b{font-size:18px}.brand span{display:none}.header-right{gap:6px}.header-right button{font-size:11px;padding:7px 10px}.header-right #help{min-width:32px;width:32px}.xync{display:none}#intro{left:20px;top:auto;bottom:95px;transform:none;width:min(330px,calc(100% - 40px));padding:22px}h1{font-size:42px;margin:10px 0 16px}#intro p:not(.eyebrow){font-size:12px}#intro .primary{margin-top:17px;padding:15px}#intro small{font-size:10px}#navigation{bottom:47px;width:calc(100% - 30px);padding:7px;gap:5px;justify-content:center;flex-wrap:wrap}#navigation button{padding:10px 12px}.tools{padding-left:6px}#scene-note{left:20px;bottom:153px}#scene-note p{max-width:250px;font-size:10px}#clock{right:20px;bottom:153px}#scene-note .eyebrow{font-size:9px}footer{left:20px;right:20px;font-size:8px;bottom:12px}footer span{display:none}body.panel-open #viewport{right:0;bottom:42vh}body.panel-open #panel{top:58vh;width:100%;padding:18px 22px 35px;border-radius:15px 15px 0 0}body.panel-open header{right:20px}body.panel-open #navigation,body.panel-open #scene-note,body.panel-open #clock,body.panel-open footer{display:none}#panel h2{font-size:24px;margin:14px 0}#panel p{font-size:14px;line-height:1.9}#panel .primary{padding:14px 18px}#mini-return{left:16px;top:calc(58vh - 55px);bottom:auto;font-size:11px;padding:11px 15px}#toast{bottom:46vh;width:max-content;max-width:90vw;font-size:12px}dialog{padding:25px}.mini-help{font-size:12px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;animation-duration:0s!important;transition-duration:0s!important}}
#panel-body fieldset{min-inline-size:0}
/* Flex rows must start below the full-width floated legend. */
#panel-body fieldset>.options{clear:both;width:100%}
#panel-body fieldset>.options button{white-space:normal;min-width:72px}
.tatami-views{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:22px 0 16px}.tatami-views button{border:1px solid var(--line);padding:13px 10px;font-size:13px;text-align:center;line-height:1.6}.tatami-views button.active{background:#dfe5d4;border-color:#829073}.material-reading{border-left:2px solid #9aa27d;padding:1px 0 6px 16px;margin:12px 0 24px}.material-reading h3{margin:8px 0;font-size:16px}.material-reading p{font-size:14px!important;line-height:1.95;margin:8px 0}.tatami-build{border-top:1px solid var(--line);padding-top:19px}.tatami-build>span{font-size:12px;color:var(--muted)}.tatami-progress{display:flex;gap:6px;flex-wrap:wrap;margin:12px 0}.tatami-progress b{padding:5px 7px;background:#e8e8de;font-size:11px;font-weight:500;line-height:1.7}.tatami-progress b.done{background:#dbe5d0}.tatami-build .primary{margin-top:12px}.tatami-learning{margin:26px 0}.tatami-fact{border-top:1px solid var(--line);padding:16px 0}.tatami-fact:last-child{border-bottom:1px solid var(--line)}.tatami-fact summary{font-size:14px;line-height:1.8;cursor:pointer;padding-right:8px}.tatami-fact p{font-size:13px!important;line-height:2}.tatami-fact .design-reading{color:#65755b;padding-left:12px;border-left:2px solid #bcc6ad}
.reference-photo{margin:24px 0;border-top:1px solid var(--line);padding-top:20px}.reference-photo button{display:block;width:100%;padding:0;text-align:left}.reference-photo img{display:block;width:100%;max-height:250px;object-fit:cover}.reference-photo span{display:block;padding:9px 0;font-size:10px;letter-spacing:.06em}.reference-photo figcaption{font-size:12px;line-height:1.8}.photo-credit{font-size:10px;line-height:1.8;margin-top:10px;color:var(--muted);overflow-wrap:anywhere}.photo-credit a{font-size:10px!important}.photo-large{width:100%;max-height:60vh;object-fit:contain}.roof-methods{margin:22px 0}.roof-methods section{border-left:2px solid #93a17b;padding:1px 0 1px 15px;margin:18px 0}.roof-methods b{font-size:15px}.roof-methods p{font-size:13px!important;margin:5px 0}.craft-details{border-block:1px solid var(--line);padding:14px 0}.craft-details summary{font-size:13px;cursor:pointer}.craft-details p{font-size:13px!important}

/* Quiet volume control: no redundant on/off switch. */
#sound-popover{position:absolute;z-index:12;top:76px;right:32px;width:280px;padding:20px;background:#f5f1e7f5;border:1px solid #fff8;box-shadow:0 12px 40px #10241e33;backdrop-filter:blur(15px)}
#sound-popover label{font-size:13px;font-weight:500}#sound-popover p{font-size:11px;line-height:1.7;margin:4px 0;color:var(--muted)}
body.panel-open #sound-popover{right:438px}
.seasons{display:grid;grid-template-columns:repeat(4,1fr)}#panel-body fieldset>.seasons button{min-width:0;padding:12px 4px}
.season-note{clear:both;font-size:13px!important;color:var(--muted)}
#save-view{display:block;margin-top:16px}
#intro{width:430px}#intro h1{font-size:clamp(33px,3.5vw,48px);line-height:1.6;letter-spacing:.025em}
@media(max-width:1050px){body.panel-open #sound-popover{right:382px}}
@media(max-width:760px){#sound-popover,body.panel-open #sound-popover{right:16px;top:67px;width:260px}#intro{width:calc(100% - 40px);max-width:360px}#intro h1{font-size:32px}.header-right{gap:4px}.header-right button{min-width:30px;padding:7px 9px}.brand b{font-size:16px;letter-spacing:.17em}header{left:16px;right:16px}}

.footer-links{display:flex;gap:20px}.header-right{gap:8px}@media(max-width:760px){.footer-links{gap:14px}.header-right{gap:4px}}

.roof-views{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:6px;margin:20px 0 12px}.roof-views button{padding:12px 6px;min-width:0}.roof-progress{margin:24px 0 14px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;color:var(--ink)}.roof-progress progress{width:100%;height:5px;accent-color:#526a4b}.auto-weather{margin:24px 0;border-top:1px solid #ccd0c4;padding-top:12px}.auto-weather h3{font-size:17px}.joint-types{flex-wrap:wrap}

.wall-study{padding:20px 0;border-block:1px solid #d7d9cb;margin:24px 0}.wall-study svg{display:block;width:100%;height:auto}.wall-stage-buttons{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-top:14px}.wall-stage-buttons button{padding:12px 8px;min-width:0;text-align:left;font-size:13px}#wall-layer-note{padding:18px 0}#wall-layer-note small{display:block;margin-bottom:14px}

/* Back stays within reach while reading a long lesson. */
.vr-entry{display:block;margin-top:12px;padding:13px 18px;border:1px solid #abb9ac;background:#223b32;color:#f7f4e8;font-size:14px;letter-spacing:.04em}
.vr-entry[hidden]{display:none}
body.in-vr>header,body.in-vr>#intro,body.in-vr>#navigation,body.in-vr>#scene-note,body.in-vr>#clock,body.in-vr>#panel,body.in-vr>#sound-popover,body.in-vr>footer,body.in-vr>#mini-return,body.in-vr>#restore-ui,body.in-vr>#toast{display:none!important}
body.in-vr #viewport{inset:0;width:100%;height:100%}
body.in-vr #hover-label,body.in-vr #view-fade{display:none}
.panel-head{position:sticky;top:-30px;z-index:3;background:#f5f1e7;padding:10px 0 14px;margin-top:-10px;gap:16px}
.panel-head #panel-back{width:auto;min-height:44px;height:auto;font-size:14px;text-align:left;padding:8px 10px 8px 0}
#panel-kicker{margin:18px 0 0;font-size:10px}
@media(max-width:1050px){.panel-head{top:-22px}}
@media(max-width:760px){.panel-head{top:-18px}}
body.quest-title #viewport{background:#17261f url('./assets/quest-title.jpg') center/cover no-repeat}
body.quest-title #scene{visibility:hidden}
body.quest-title #intro{backdrop-filter:none;background:#f5f1e7f5}
body.quest-title #sound,body.quest-title #season-open,body.quest-title footer{display:none}
body.quest-title #quest-status{font-size:13px;line-height:1.7;margin:14px 0 0}
body.quest-device #loading i{animation:none}
body.quest-device #navigation,body.quest-device dialog::backdrop{backdrop-filter:none}