/* Original material campaign and instruction-led product education. */
.durability-section{background:#080808;color:#fff;padding:100px 0 58px}
.durability-heading{display:grid;grid-template-columns:1.2fr .8fr;gap:80px;align-items:end;margin-bottom:52px}
.durability-heading h2{font-size:clamp(36px,4.6vw,68px);line-height:1.16;margin-top:23px;max-width:760px}
.durability-heading .eyebrow{color:#999}.durability-heading p{color:#aaa;font-size:17px;max-width:420px;margin-bottom:22px}
.durability-heading .button{color:#eee;border-color:#666;background:transparent}
.durability-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:44px 24px}
.durability-card{min-width:0}.durability-card figure{position:relative;overflow:hidden;background:#111;aspect-ratio:3/2}
.durability-card img{width:100%;height:100%;display:block;object-fit:cover;transition:transform .7s ease}
.durability-card:hover img{transform:scale(1.025)}
.durability-label{position:absolute;left:24px;top:23px;color:#fff;font:13px/1.4 ui-monospace,monospace;letter-spacing:.07em;background:transparent;padding:0}
.durability-copy{padding:24px 4px 0}.durability-copy h3{font-size:clamp(22px,2.1vw,31px);line-height:1.35;letter-spacing:-.025em;color:#f5f5f5;margin-bottom:13px}
.durability-copy p{font-size:16px;line-height:1.85;max-width:530px;color:#a5a5a5;margin-bottom:0}
.visual-note{font-size:12px;line-height:1.75;letter-spacing:.015em;color:#888;margin:35px 0 0}
.test-reference{font-size:13px;line-height:1.85;color:#aaa;margin-top:22px;border-top:1px solid #333;padding-top:22px;max-width:1000px}
.guide-preview .section-intro{margin-bottom:35px}.quick-steps{list-style:none;display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:20px;padding:0;margin:0 0 35px}
.quick-steps li{border-top:1px solid #bdbdbd;padding-top:20px;display:flex;flex-direction:column;gap:13px}.quick-steps span{font:13px/1.5 ui-monospace,monospace;color:#888}.quick-steps b{font-size:23px;font-weight:500}
.guide-actions{margin-top:30px;gap:14px}.letter-guide{display:grid;grid-template-columns:1.08fr .92fr;gap:66px;align-items:start;padding-top:22px;padding-bottom:85px}
.letter-explanation{min-width:0}.letter-explanation h2{font-size:clamp(38px,4.2vw,62px);line-height:1.15;margin:24px 0}.letter-explanation>p{color:#666;max-width:620px;font-size:16px}
.letter-explanation .letter-example{font:22px/1.5 ui-monospace,monospace;letter-spacing:.04em;color:#222;margin:25px 0}.letter-example span{color:#999;margin-inline:14px}.letter-example strong{font-weight:500;color:#d44b12}
.letter-positions{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1px;background:#c4c4c4;border:1px solid #c4c4c4;width:min(100%,380px);margin:25px 0 15px}
.letter-position{background:#f3f3f3;min-height:132px;padding:16px 20px;display:flex;flex-direction:column;align-items:flex-start;justify-content:space-between}.letter-position span{font-size:12px;line-height:1.5;color:#777}.letter-position b{font:40px/1 ui-monospace,monospace;color:#181818;font-weight:400;align-self:center;margin-bottom:8px}
.letter-position:nth-child(2),.letter-position:nth-child(4){border-left:0}.letter-explanation .micro-copy{font-size:13px;line-height:1.7;max-width:480px}.letter-rules{margin-top:30px;border-top:1px solid #d0d0d0;padding-top:22px}.letter-rules p{display:grid;grid-template-columns:155px 1fr;gap:18px;font-size:14px;line-height:1.75;margin-bottom:17px;color:#777}.letter-rules b{font-size:14px;font-weight:500;color:#222}
.letter-product{background:#000;position:sticky;top:112px;aspect-ratio:4/5;overflow:hidden}.letter-product img{width:100%;height:100%;object-fit:contain;padding:20px 10px 60px}.letter-product figcaption{position:absolute;bottom:22px;left:24px;right:24px;color:#a5a5a5;font-size:12px;text-align:center;line-height:1.7}
.operation-section{display:grid;grid-template-columns:.85fr 1.15fr;gap:85px;border-top:1px solid #ddd}.operation-intro{position:sticky;top:120px;align-self:start}.operation-intro h2{font-size:clamp(35px,4vw,56px);line-height:1.2;margin:22px 0}.operation-intro p{font-size:16px;color:#777;max-width:410px}.operation-steps{list-style:none;margin:0;padding:0}.operation-steps li{display:grid;grid-template-columns:42px 1fr;gap:24px;border-top:1px solid #cfcfcf;padding:30px 0}.operation-number{font:14px/1.7 ui-monospace,monospace;color:#c6501e;padding-top:4px}.operation-steps h3{font-size:25px;line-height:1.4;margin:0 0 13px}.operation-steps p{font-size:16px;line-height:1.85;margin:0;color:#666}
.guide-check{display:grid;grid-template-columns:1fr 1.1fr;gap:75px;align-items:center}.guide-check h2{font-size:clamp(33px,3.5vw,52px);line-height:1.2;margin:23px 0}.guide-check p{font-size:16px;line-height:1.85;color:#666;max-width:430px}.guide-check .checklist-card{margin:0;max-width:none}
.original-manual details{border-top:1px solid #ccc;border-bottom:1px solid #ccc}.original-manual summary{padding:27px 0;display:flex;justify-content:space-between;gap:30px;align-items:center;cursor:pointer;list-style:none}.original-manual summary::-webkit-details-marker{display:none}.original-manual summary>span:first-child{display:flex;flex-direction:column;gap:9px}.original-manual summary small{font-size:12px;color:#888;letter-spacing:.045em}.original-manual summary b{font-size:26px;font-weight:500;line-height:1.4}.manual-plus{font-size:32px;font-weight:300;padding:5px 14px;transition:transform .2s}.original-manual details[open] .manual-plus{transform:rotate(45deg)}.manual-expanded{padding:15px 0 35px}.manual-expanded p{font-size:16px;color:#666;max-width:740px}.manual-expanded img{display:block;width:100%;max-width:980px;height:auto;margin:30px auto;background:white}.manual-expanded .button{margin-top:15px}
.material-pair{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}.material-pair img{aspect-ratio:3/2;height:auto;width:100%;object-fit:cover}.product-materials .visual-note{color:#888;margin-top:18px}
@media(max-width:960px){.durability-heading{gap:40px;grid-template-columns:1fr 1fr}.durability-section{padding-top:75px}.durability-heading h2{font-size:44px}.durability-copy h3{font-size:24px}.letter-guide{gap:35px}.letter-product{aspect-ratio:3/5}.letter-rules p{grid-template-columns:1fr;gap:4px}.operation-section{gap:40px}.guide-check{gap:40px}.operation-steps li{gap:16px;grid-template-columns:32px 1fr}.quick-steps b{font-size:20px}}
@media(max-width:700px){.durability-section{padding:58px 0 42px}.durability-heading{grid-template-columns:1fr;gap:22px;margin-bottom:30px}.durability-heading h2{font-size:clamp(32px,8.7vw,45px);margin-top:20px;line-height:1.24}.durability-heading p{font-size:16px;margin-bottom:15px}.durability-grid{grid-template-columns:1fr;gap:36px}.durability-card figure{aspect-ratio:3/2}.durability-label{top:14px;left:14px;font-size:12px;padding:0}.durability-copy{padding-top:20px}.durability-copy h3{font-size:24px;line-height:1.35;margin-bottom:10px}.durability-copy p{font-size:16px}.visual-note{font-size:12px;margin-top:30px}.test-reference{font-size:13px}.quick-steps{grid-template-columns:repeat(3,minmax(0,1fr));gap:22px 18px;margin-bottom:28px}.quick-steps li{padding-top:14px;gap:10px}.quick-steps b{font-size:20px}.quick-steps span{font-size:12px}.guide-preview .button{width:100%}.guide-actions{gap:10px;margin-top:25px}.guide-actions .button{font-size:14px;min-height:48px;padding:13px 17px}.letter-guide{display:flex;flex-direction:column;gap:32px;padding-top:5px;padding-bottom:55px}.letter-explanation h2{font-size:37px;margin-top:20px}.letter-explanation>p{font-size:16px}.letter-explanation .letter-example{font-size:20px}.letter-example span{margin-inline:8px}.letter-positions{width:100%}.letter-position{min-height:124px;padding:14px 18px}.letter-position span{font-size:13px}.letter-position b{font-size:37px}.letter-product{position:relative;top:auto;width:100%;aspect-ratio:1/1.1}.letter-product img{padding:22px 10px 53px}.letter-product figcaption{font-size:11px;left:16px;right:16px;bottom:17px}.letter-rules{margin-top:24px;padding-top:21px}.letter-rules p{font-size:14px;gap:5px;margin-bottom:18px}.letter-rules b{font-size:14px}.operation-section{display:block}.operation-intro{position:static;margin-bottom:26px}.operation-intro h2{font-size:36px;margin:20px 0}.operation-intro p{font-size:16px}.operation-steps li{padding:25px 0;gap:14px;grid-template-columns:31px 1fr}.operation-steps h3{font-size:23px}.operation-steps p{font-size:16px}.operation-number{font-size:13px}.guide-check{grid-template-columns:1fr;gap:23px}.guide-check h2{font-size:35px}.guide-check .checklist-card{padding:24px}.original-manual summary{gap:15px;padding:23px 0}.original-manual summary b{font-size:22px}.original-manual summary small{font-size:11px}.manual-plus{padding:5px 6px}.manual-expanded .button{width:100%;font-size:14px}.material-pair{grid-template-columns:1fr;gap:18px}.product-materials .section-intro h2{font-size:31px}}
@media(prefers-reduced-motion:reduce){.durability-card img,.manual-plus{transition:none}.durability-card:hover img{transform:none}}