/* TDesign-inspired public surface */
body{background:#f5f7fa;color:#1d2733}.topbar{height:64px;padding:0 max(20px,calc((100vw - 1180px)/2));border-bottom:1px solid #e7ebf0;box-shadow:none}.brand{font-size:18px;color:#1d2733}.topbar nav{gap:18px;font-size:13px}.topbar nav .button{background:#0052d9;border-radius:4px;padding:7px 13px}.container{max-width:1180px;padding-top:42px}.hero{padding:56px 0 42px}.hero h1{font-size:clamp(38px,6vw,64px);max-width:760px;color:#182430}.hero p{font-size:17px}.hero .button{background:#0052d9;border-radius:4px}.feature-grid div,.panel,.course-card,.auth-card{border-color:#e1e7ef;border-radius:6px;box-shadow:none}.feature-grid div{padding:22px}.feature-grid div:hover,.course-card:hover{border-color:#9cc2f5;transform:none}.course-card{background:#fff}.course-card h2,.course-card h3{color:#1d2733}.auth-card{border-radius:6px;margin-top:35px}.auth-card h1{font-size:28px}.auth-card .button{background:#0052d9;border-radius:4px}.flash{border-radius:4px}.course-layout{gap:24px}.course-sidebar{border-color:#e1e7ef;border-radius:6px;box-shadow:none}.sidebar-title{color:#1d2733}.course-sidebar a{border-radius:4px}.course-sidebar a:hover,.course-sidebar a.active{background:#e8f1ff;color:#0052d9}.lesson-content h1{color:#1d2733}.video-wrap,.video-placeholder{border-radius:6px}.markdown{font-size:16px}.markdown h1,.markdown h2,.markdown h3{color:#1d2733}.player-tools .button{border-radius:4px}.empty{border-radius:6px}@media(max-width:800px){.container{padding:28px 16px 56px}.topbar{padding:0 16px}.hero{padding:32px 0}.course-layout{gap:16px}}