.tutorial-main{max-width:1200px;padding-bottom:64px}.tutorial-heading{padding:125px 0 36px;text-align:center}.tutorial-heading h1{font-size:clamp(40px,5vw,64px);line-height:1.1;margin:0;font-weight:800;letter-spacing:-1px}#lesson-library{color:#f5f3ee;margin:0;padding:0;background:transparent;border:0}#lesson-library [hidden]{display:none!important}.lesson-stage{padding:30px 0 36px;border-bottom:1px solid #ffffff16;scroll-margin-top:90px}.lesson-stage-title{display:flex;gap:16px;align-items:center;justify-content:center;text-align:center;margin-bottom:24px}.lesson-stage-title h2{font-size:25px;margin:0}.lesson-number{font-size:13px;letter-spacing:2px;color:#ffffff;border:1px solid #ffffff55;border-radius:50%;width:38px;height:38px;display:grid;place-items:center;flex-shrink:0}.lesson-model-label{display:block;font-size:14px;color:#b8b9bf;margin-bottom:8px}#lesson-model{max-width:360px;background:#191b20;color:#fff;border:1px solid #5b6068;margin-bottom:24px;color-scheme:dark}.lesson-models{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}.lesson-model-card{padding:22px 14px 17px;display:flex;flex-direction:column;align-items:center;gap:18px;font:600 18px ploni,Arial,sans-serif;color:#d6d6db;background:linear-gradient(145deg,#1e2025,#131519);border:1px solid #ffffff20;border-radius:16px;cursor:pointer;transition:border-color .2s,background .2s,transform .2s}.lesson-keys{display:flex;gap:2px;width:105px;height:29px;direction:ltr;padding:5px 5px 3px;border-radius:4px;background:#3d4046;border-top:5px solid #55585e}.lesson-keys i{display:block;flex:1;background:#c5c5c6;border-radius:0 0 2px 2px;position:relative}.lesson-keys i:not(:nth-child(3n)):not(:last-child):after{content:'';position:absolute;right:-3px;top:0;width:4px;height:15px;background:#111318;z-index:1}.lesson-model-card[aria-pressed=true]{background:linear-gradient(140deg,#263441,#161c23);color:#ffffff;border-color:#ffffff;box-shadow:0 0 0 1px #ffffff30}.lesson-model-card[aria-pressed=true] .lesson-keys{border-top-color:#b49a60}.lesson-categories{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:14px}.lesson-category{font:inherit;border:1px solid #ffffff24;border-radius:18px;background:#17191e;color:#eee;padding:24px 18px;cursor:pointer;text-align:right;display:flex;flex-direction:column;align-items:start;gap:14px}.lesson-category-icon{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:#ffffff12;color:#ffffff;font-size:26px}.lesson-category strong{font-size:18px;line-height:1.4}.lesson-category small{font-size:14px;color:#a7a8af;margin-top:auto}.lesson-category[aria-pressed=true]{border-color:#ffffff;background:linear-gradient(145deg,#263441,#161c23)}#lesson-overview{color:#a7a8af;margin:0 0 20px;font-size:16px}.lesson-topics{display:grid;grid-template-columns:1fr 1fr;gap:12px}.lesson-topic-card{text-align:right;display:grid;grid-template-columns:1fr 24px;gap:8px 16px;font:inherit;padding:22px 24px;background:#17191d;color:#eee;border:1px solid #ffffff21;border-radius:14px;cursor:pointer}.lesson-topic-card strong{font-size:18px}.lesson-topic-card small{grid-column:1;color:#aaaeb7;font-size:14px}.lesson-topic-card>span{grid-column:2;grid-row:1/3;align-self:center;color:#ffffff;font-size:24px}.lesson-topic-card[aria-pressed=true]{border-color:#ffffff;background:#222832}.lesson-model-card:hover,.lesson-category:hover,.lesson-topic-card:hover{border-color:#ffffff}.lesson-model-card:hover{transform:translateY(-2px)}#lesson-library button:focus-visible,#lesson-library summary:focus-visible{outline:2px solid #ffffff;outline-offset:4px}#lesson-body{scroll-margin-top:100px;margin:28px 0;padding:32px;border:1px solid #ffffff55;border-radius:22px;background:linear-gradient(140deg,#202126,#14161a)}#lesson-body h3{margin:0 0 24px;font-size:26px}.lesson-instruction{font-size:23px;line-height:1.9;padding:24px;background:#ffffff05;border:1px solid #ffffff10;border-radius:14px}.lesson-count{color:#ffffff;font-size:15px}.lesson-controls{display:flex;gap:12px;flex-wrap:wrap}.learn-action{font:600 17px ploni,Arial,sans-serif;cursor:pointer;background:#ffffff;color:#151515;border:1px solid #ffffff;border-radius:12px;padding:14px 22px}.lesson-controls .learn-action:first-child{background:transparent;color:#ffffff;border-color:#5b6068}.learn-action:disabled{opacity:.35;cursor:default}.lesson-warning{border-right:3px solid #ffffff;background:#ffffff12;color:#eeeeee;padding:18px;line-height:1.8;border-radius:8px}#lesson-library details{padding:18px 0;border-top:1px solid #ffffff17;margin-top:20px;line-height:1.9}#lesson-library summary{cursor:pointer;font-weight:600}#lesson-library a{color:#ffffff;text-underline-offset:5px}#lesson-library li{margin:12px 0}#lesson-status{color:#b8b2a5;line-height:1.7;margin:20px 0}#lesson-status:empty{display:none}.tutorial-videos{margin-top:40px;border:1px solid #ffffff20;border-radius:16px;padding:22px 26px;background:#111317}.tutorial-videos>summary{display:flex;justify-content:space-between;cursor:pointer;font-size:20px;list-style:none}.tutorial-videos>summary::-webkit-details-marker{display:none}.tutorial-videos>summary span{color:#ffffff}.tutorial-videos .learn-library{padding-bottom:12px}.tutorial-videos .learn-card{min-height:180px}
@media(max-width:900px){.lesson-categories{grid-template-columns:repeat(3,minmax(0,1fr))}.lesson-stage-title h2{font-size:23px}}
@media(max-width:600px){.tutorial-heading{padding:105px 0 18px}.lesson-stage{padding:24px 0}.lesson-models{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.lesson-model-card{padding:18px 12px;font-size:16px}.lesson-categories{grid-template-columns:1fr 1fr;gap:10px}.lesson-category{padding:18px 14px;gap:12px}.lesson-category strong{font-size:17px}.lesson-topics{grid-template-columns:1fr}.lesson-topic-card{padding:19px}.lesson-stage-title{gap:12px}.lesson-stage-title h2{font-size:22px}#lesson-body{padding:22px 18px}#lesson-body h3{font-size:22px}.lesson-instruction{font-size:20px;padding:18px}.lesson-controls button{width:100%}.tutorial-videos{padding:20px 16px}.tutorial-videos>summary{font-size:18px}#lesson-model{max-width:none}}
@media(prefers-reduced-motion:reduce){.lesson-model-card{transition:none}.lesson-model-card:hover{transform:none}}

/* Three organ families, using the simulator photography. */
.lesson-models{grid-template-columns:repeat(3,minmax(0,1fr));margin-bottom:24px}.lesson-model-card{padding:24px 18px;gap:16px;font-size:23px}.lesson-model-card img{display:block;width:100%;max-width:300px;height:130px;object-fit:contain;filter:drop-shadow(0 10px 12px #0005)}
@media(max-width:600px){.lesson-models{gap:8px;grid-template-columns:repeat(3,minmax(0,1fr))}.lesson-model-card{padding:16px 8px;font-size:18px;gap:10px;border-radius:12px}.lesson-model-card img{height:65px}}

.lesson-manual-links{display:flex;gap:10px;flex-wrap:wrap;margin:16px 0 24px}.lesson-manual-links a{padding:9px 13px;border:1px solid #ffffff55;border-radius:9px;font-size:15px;background:#ffffff09}

/* The native screen and adjacent controls remain together at every viewport size. */
.lesson-visual{max-width:760px;margin:24px auto;text-align:center}.lesson-visual-frame{direction:ltr;position:relative;line-height:0}.lesson-visual-frame img{display:block;width:100%;height:auto;border-radius:10px}.lesson-visual-pin{position:absolute;width:24px;height:24px;border:3px solid #ff3f4e;border-radius:50%;transform:translate(-50%,-50%);box-shadow:0 0 0 2px #fff;pointer-events:none}.lesson-visual figcaption{font-size:15px;color:#c8c8cc;margin:12px 0 8px}.lesson-visual a{display:inline-block;padding:8px;font-size:15px}.lesson-visual-overview{max-width:440px}.lesson-visual-note{font-size:16px;line-height:1.8;color:#c8d0d8;margin:18px 0}.lesson-categories{grid-template-columns:repeat(3,minmax(0,1fr))}@media(max-width:600px){.lesson-categories{grid-template-columns:repeat(2,minmax(0,1fr))}.lesson-visual-pin{width:18px;height:18px;border-width:2px}.lesson-visual-note{font-size:15px}#lesson-body{padding:18px 10px}}

/* Focused lesson reader: one active screenshot beside its instruction. */
#lesson-library.lesson-reading>.lesson-stage,#lesson-library.lesson-reading>#lesson-status{display:none!important}
#lesson-body{scroll-margin-top:90px;padding:24px;min-width:0}
.lesson-toolbar{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:14px;color:#aaa}
.lesson-toolbar .lesson-back{background:transparent;color:inherit;border-color:#ffffff30;padding:10px 14px;font-size:15px}
#lesson-body h3{margin-bottom:20px;font-size:clamp(21px,2.2vw,28px);line-height:1.4}
.lesson-workspace{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(260px,1fr);gap:24px;align-items:start;direction:ltr}
.lesson-screen,.lesson-explanation{direction:rtl;min-width:0}
.lesson-screen{background:#0d0f12;border:1px solid #ffffff1a;border-radius:16px;padding:14px}
.lesson-screen .lesson-visual{margin:12px auto 0;max-width:100%;width:100%}
.lesson-screen .lesson-visual-overview{max-width:100%}
.lesson-visual-frame{width:100%;margin:auto}
.lesson-visual figcaption{font-size:14px;line-height:1.4;margin:10px 0 0}
.lesson-visual a{font-size:14px;padding:8px}
.lesson-view-tabs{display:flex;justify-content:center;gap:6px}
.lesson-view-tabs .learn-action{font-size:14px;padding:9px 13px;background:transparent;color:#ddd;border-color:#ffffff30}
.lesson-view-tabs .learn-action[aria-pressed=true]{background:#ffffff;color:#151515;border-color:#ffffff}
.lesson-explanation .lesson-count{margin:0 0 8px;font-size:16px}
.lesson-explanation progress{width:100%;height:5px;accent-color:#ffffff;display:block;margin-bottom:16px}
.lesson-explanation .lesson-instruction{margin:0;padding:0;border:0;background:none;font-size:21px;line-height:1.7}
.lesson-explanation .lesson-visual-note{font-size:14px;line-height:1.6;margin:14px 0;color:#b9bac0}
.lesson-controls{margin-top:22px;display:grid;grid-template-columns:1fr 1.4fr;gap:8px}
.lesson-controls .learn-action{font-size:15px;padding:12px 10px;width:auto;line-height:1.4}
.lesson-step-select{display:block;width:100%;min-width:0;max-width:100%;text-overflow:ellipsis;background:#17191e;color:#eee;border:1px solid #ffffff30;border-radius:10px;padding:10px;margin-top:12px;font:inherit;font-size:14px}
#lesson-body details{font-size:15px;padding:12px 0;margin-top:12px}
#lesson-body .lesson-warning{font-size:15px;padding:12px;margin:10px 0 16px}
@media(max-width:760px){#lesson-body{padding:16px 12px}.lesson-workspace{grid-template-columns:1fr;gap:18px}.lesson-explanation .lesson-instruction{font-size:19px;line-height:1.65}.lesson-screen{padding:10px}.lesson-toolbar{font-size:14px}.lesson-toolbar .lesson-back{font-size:14px;padding:8px}.lesson-screen .lesson-visual{margin-top:10px}.lesson-controls{position:sticky;bottom:8px;background:#17191e;padding:8px;border-radius:12px;z-index:2}.lesson-view-tabs .learn-action{font-size:13px}}

.lesson-screen .lesson-visual-frame{width:min(100%,calc(48vh * var(--image-ratio,1.5)))}@media(max-width:760px){.lesson-screen .lesson-visual-frame{width:min(100%,calc(34vh * var(--image-ratio,1.5)))}}

/* Center the selector hierarchy without changing RTL lesson instructions. */
.lesson-model-label{text-align:center}#lesson-model{display:block;margin-inline:auto;text-align:center;text-align-last:center}.lesson-number{display:none}.lesson-stage-title h2{width:100%;text-align:center}#yu-guides>h1{text-align:center}
/* Also cover cached markup from before the numbered stages were removed. */
#lesson-category-stage>.lesson-stage-title,#lesson-overview{display:none}

#yu-guides{font-family:ploni,Arial,sans-serif;direction:rtl;color:#fff;max-width:1160px;margin:auto;padding:100px 24px 70px}#yu-guides *{box-sizing:border-box}#yu-guides h1{font-family:ploni,Arial,sans-serif;font-size:clamp(44px,6vw,78px);line-height:1.15;margin:0 0 30px}#yu-guides button,#yu-guides select{font-family:inherit}#yu-guides select{width:100%;padding:14px;border-radius:12px}#yu-guides button{white-space:normal}#yu-guides .lesson-model-card[aria-pressed=true]{box-shadow:0 0 26px #fff1}#yu-guides .lesson-instruction{color:#fff}#yu-guides .lesson-visual-pin{border-color:#ff3f4e!important}@media(max-width:600px){#yu-guides{padding:85px 16px 40px}#yu-guides .lesson-model-card img{height:60px}#yu-guides h1{font-size:44px}}

#yu-guides button{color:#fff;border-color:#ffffff35;border-radius:16px}#yu-guides button[aria-pressed=true]{color:#fff;border-color:#fff;background:linear-gradient(140deg,#263441,#161c23)}#yu-guides button:hover{color:#fff;border-color:#fff}#yu-guides .learn-action{color:#111;background:#fff;border-color:#fff}#yu-guides .lesson-controls .learn-action:first-child{color:#fff;background:transparent;border-color:#777}#yu-guides h1,#yu-guides h2{font-weight:700}