:root{--ink:#10283d;--paper:#f7f3e8;--sun:#ffcb47;--sky:#4dbff5;--line:#17324d33}*{box-sizing:border-box}.platform-page{background:var(--paper);color:var(--ink);min-height:100vh;margin:0;font-family:Noto Sans KR,sans-serif}.platform-header{border-bottom:2px solid var(--ink);z-index:10;background:#fff;align-items:center;gap:32px;height:76px;padding:0 clamp(20px,5vw,72px);display:flex;position:sticky;top:0}.platform-brand{color:var(--ink);font:28px Black Han Sans;text-decoration:none}.platform-brand span,.platform-hero h1 span{color:#e8543e}.platform-header nav{gap:22px;margin-right:auto;display:flex}.platform-header a{color:inherit;font-weight:800}.platform-button,.course-search button,.code-jump button,.auth-actions button{border:2px solid var(--ink);background:var(--sun);cursor:pointer;min-height:48px;padding:0 20px;font-weight:800}.platform-shell{max-width:1320px;margin:auto;padding:56px clamp(20px,5vw,72px)}.platform-hero{grid-template-columns:1fr auto;align-items:end;gap:48px;padding:50px 0 72px;display:grid}.platform-hero h1{margin:10px 0;font:clamp(44px,7vw,92px)/.98 Black Han Sans}.code-jump{border:2px solid var(--ink);box-shadow:8px 8px 0 var(--sky);background:#fff;gap:10px;padding:22px;display:grid}input{font:inherit;border:2px solid var(--ink);min-height:48px;padding:0 14px}.course-world-bar{border-bottom:2px solid var(--ink);justify-content:space-between;align-items:center;display:flex}.course-world h2{font:36px Black Han Sans}.tabs button{background:0 0;border:0;min-height:48px;padding:0 18px;font-weight:800}.tabs button[aria-selected=true]{background:var(--ink);color:#fff}.course-search{gap:10px;margin:28px 0;display:flex}.course-search input{flex:1}.course-grid{grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:24px;display:grid}.course-card{border:2px solid var(--ink);box-shadow:5px 5px 0 var(--ink);background:#fff;position:relative}.course-card a{color:inherit;text-decoration:none}.course-thumbnail{aspect-ratio:16/9;border-bottom:2px solid var(--ink);background:linear-gradient(#4dbff5,#dff5ff);place-items:center;display:grid;overflow:hidden}.course-thumbnail img{object-fit:cover;width:100%;height:100%}.course-thumbnail span{color:#fff;font:64px Black Han Sans}.course-card-body{padding:18px}.course-card h3{margin:4px 0;font-size:22px}.course-author{color:#397893;font-weight:800}.course-card dl{gap:24px;display:flex}.course-card dt{font-size:12px}.course-card dd{margin:0;font-weight:800}.like-button{border:2px solid var(--ink);background:#fff;min-height:44px;margin:0 18px 18px}.platform-status{min-height:24px}.auth-dialog{border:2px solid var(--ink);width:min(460px,100% - 32px);box-shadow:8px 8px 0 var(--ink);padding:30px}.auth-dialog::backdrop{background:#10283dcc}.auth-dialog label{gap:5px;margin:16px 0;font-weight:800;display:grid}.auth-actions{gap:10px;display:flex}.dialog-close{float:right;background:0 0;border:0;font-size:30px}.sr-only{clip:rect(0,0,0,0);width:1px;height:1px;position:absolute;overflow:hidden}@media (max-width:767px){.platform-header{flex-wrap:wrap;height:auto;padding:12px 16px}.platform-header nav{order:3;width:100%}.platform-shell{padding:24px 16px}.platform-hero{grid-template-columns:1fr;padding:24px 0 42px}.code-jump{min-width:0}.code-jump input{width:100%;min-width:0}.course-world-bar{align-items:flex-end}.tabs button,.platform-button,.course-search button{min-height:52px}.course-search{flex-direction:column}}@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}.official-world{margin-bottom:64px}.official-card .course-thumbnail{background:linear-gradient(145deg,#17324d,#4dbff5)}.course-thumbnail .course-difficulty{z-index:1;background:var(--sun);border:2px solid var(--ink);color:var(--ink);padding:4px 10px;font-size:12px;font-weight:800;line-height:1;position:absolute;top:10px;left:10px}.course-card dl{flex-wrap:wrap}