.learn-site{min-height:100%;height:auto;overflow-x:hidden;overflow-y:auto;background:var(--ink);color:var(--text)}.site-header{position:sticky;top:0;z-index:5;display:flex;align-items:center;justify-content:space-between;gap:20px;padding:16px max(24px,calc((100vw - 900px)/2));background:#12181aef;border-bottom:1px solid #ffffff12;backdrop-filter:blur(14px)}.brand-name{font:700 20px var(--font-display);text-decoration:none;color:var(--text)}.brand-name span{color:var(--ball)}.site-header nav{display:flex;gap:24px}.site-header nav a{color:var(--text-dim);font-size:12px;text-decoration:none;padding:10px 0}.site-header nav a:hover,.site-header nav a[aria-current=page]{color:var(--ball)}.rules-page{width:min(900px,calc(100% - 40px));margin:0 auto}.back-link{display:inline-block;margin:24px 0 0;color:var(--text-dim);font-size:12px;text-decoration:none}.back-link:hover{color:var(--ball)}.rules-hero{padding:38px 0 44px;border-bottom:1px solid var(--line)}.eyebrow{font-size:9px;letter-spacing:1.8px;color:var(--ball);margin:0 0 12px;font-weight:600}.rules-hero h1{font:500 clamp(44px,7vw,70px)/1 var(--font-display);letter-spacing:-3px;margin:0 0 16px}.rules-hero h1 em{font:italic 400 1em Georgia,serif;color:var(--ball)}.rules-hero>p:not(.eyebrow){max-width:570px;color:var(--text-dim);font-size:14px;line-height:1.75;margin:0}.rules-summary{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin-top:24px;color:var(--text);font-size:10px;letter-spacing:.6px}.rules-summary i{width:4px;height:4px;border-radius:50%;background:var(--ball)}.lesson-list{border-bottom:1px solid var(--line)}.rule-lesson{display:grid;grid-template-columns:40px minmax(0,1fr);gap:14px;padding:28px 0;border-bottom:1px solid var(--line);scroll-margin-top:90px}.rule-lesson:last-child{border:0}.lesson-number{font:500 14px var(--font-display);color:var(--ball);padding-top:3px}.lesson-main{max-width:720px}.lesson-main>.eyebrow{color:var(--text-dim);font-size:9px;margin-bottom:8px}.lesson-main h2{font:500 clamp(23px,3vw,30px)/1.2 var(--font-display);letter-spacing:-.7px;margin:0 0 10px}.main-rule{font:500 clamp(16px,2vw,19px)/1.65 var(--font-body);color:var(--text);margin:0 0 12px}.detail-copy,.extra-detail p{font-size:12px;line-height:1.75;color:var(--text-dim);margin:12px 0 0}.extra-detail{margin-top:14px;border:1px solid var(--line);border-radius:10px;background:var(--ink-raised);padding:0 12px}.extra-detail summary{cursor:pointer;min-height:42px;display:flex;align-items:center;color:var(--ball);font-size:11px;font-weight:600;list-style:none}.extra-detail summary::-webkit-details-marker{display:none}.extra-detail summary:after{content:'＋';margin-left:auto;font-size:16px}.extra-detail[open] summary:after{content:'−'}.extra-detail p{padding:0 0 12px;margin:0}.card-link{display:inline-flex;gap:8px;align-items:center;color:var(--ball);font-weight:600;font-size:12px;text-decoration:none;padding:8px 0}.card-link:hover{text-decoration:underline;text-underline-offset:4px}.card-link span{font-size:17px}.advanced{padding:42px 0 12px}.advanced>h2{font:500 30px/1.2 var(--font-display);letter-spacing:-.7px;margin:0 0 8px}.advanced-intro{color:var(--text-dim);font-size:12px;line-height:1.65;margin:0 0 18px}.advanced-card{border-top:1px solid var(--line)}.advanced-card:last-child{border-bottom:1px solid var(--line)}.advanced-card summary{display:grid;grid-template-columns:140px minmax(0,1fr) 24px;align-items:center;gap:12px;min-height:62px;cursor:pointer;list-style:none}.advanced-card summary::-webkit-details-marker{display:none}.advanced-tag{font-size:8px;letter-spacing:1.1px;color:var(--text-dim)}.advanced-card summary strong{font:500 17px var(--font-display)}.summary-arrow{font-size:18px;color:var(--ball);text-align:right}.advanced-card[open] .summary-arrow{transform:rotate(45deg)}.advanced-card>p{max-width:670px;color:var(--text-dim);font-size:12px;line-height:1.75;margin:0 32px 18px 152px}.next-step{display:flex;align-items:center;justify-content:space-between;gap:26px;padding:24px;margin:38px 0 28px;background:linear-gradient(120deg,#1b4b45,#1b2326);border:1px solid #9cbf8a55;border-radius:16px}.next-step h2{font:500 24px var(--font-display);margin:0 0 6px}.next-step p:not(.eyebrow){font-size:11px;line-height:1.6;color:var(--text-dim);margin:0}.next-step .primary-button{width:auto;flex:none;min-width:190px;text-decoration:none;min-height:50px}.sources{display:flex;gap:10px 20px;align-items:center;flex-wrap:wrap;padding:16px 0;border-top:1px solid var(--line)}.sources p{flex-basis:100%;font-size:10px;color:var(--text-dim);line-height:1.6;margin:0}.sources a{font-size:10px;color:var(--ball);text-underline-offset:3px}.site-footer{display:flex;justify-content:space-between;align-items:center;padding:20px 0 28px;border-top:1px solid var(--line);color:var(--text-dim);font-size:11px}.site-footer .brand-name{font-size:15px}
@media(max-width:560px){.site-header{padding:12px 18px}.site-header nav{gap:13px}.site-header nav a{font-size:11px}.rules-page{width:calc(100% - 34px)}.rules-hero{padding:32px 0}.rules-hero h1{letter-spacing:-2px}.rules-hero>p:not(.eyebrow){font-size:13px}.rules-summary{gap:7px;font-size:9px}.rule-lesson{grid-template-columns:26px minmax(0,1fr);gap:8px;padding:23px 0}.main-rule{font-size:16px}.detail-copy,.extra-detail p{font-size:11px}.advanced-card summary{grid-template-columns:90px minmax(0,1fr) 20px;gap:8px}.advanced-tag{font-size:7px;letter-spacing:.7px}.advanced-card summary strong{font-size:15px}.advanced-card>p{margin:0 24px 16px 98px;font-size:11px}.next-step{display:block;padding:20px}.next-step .primary-button{width:100%;margin-top:16px}.site-footer{font-size:10px}}
.site-footer small{font-size:9px;color:var(--text-dim)}

html.learn-document{height:auto;min-height:100%;overflow-x:hidden;overflow-y:auto;-webkit-overflow-scrolling:touch}.learn-site{min-height:100vh;min-height:100dvh;height:auto;overflow:visible}

.court-figure{margin:20px 0 16px;padding:16px;background:var(--ink-raised);border:1px solid var(--line);border-radius:16px}.court-map{display:block;width:100%;max-width:340px;height:auto;margin:auto;overflow:visible}.court-surface{fill:#1b4b45}.kitchen-fill{fill:#9cbf8a33}.court-lines{fill:none;stroke:#d9e3dc;stroke-width:3}.court-net{fill:none;stroke:#9cbf8a;stroke-width:5;stroke-dasharray:5 4}.map-label{fill:var(--text);font:600 14px var(--font-body);text-anchor:middle}.map-annotation{fill:var(--text-dim);font:12px var(--font-body);text-anchor:middle}.serve-target{fill:#9cbf8a55}.serve-area{fill:#9cbf8a22}.imaginary-line{fill:none;stroke:var(--ball);stroke-width:3;stroke-dasharray:7 6}.serve-flight{fill:none;stroke:var(--ball);stroke-width:4;color:var(--ball)}.server-dot{fill:var(--ball);stroke:var(--ink);stroke-width:3}.court-figure figcaption{max-width:440px;margin:10px auto 0;font-size:11px;line-height:1.65;color:var(--text-dim)}
@media(max-width:560px){.court-figure{padding:10px}.court-map{max-width:340px}}