:root{--ink:#102a43;--muted:#627d98;--line:#d9e2ec;--paper:#fff;--canvas:#f5f7fa;--red:#bd202c;--dark:#081c2c}*{box-sizing:border-box}body{color:var(--ink);background:var(--canvas);margin:0;font-family:Arial,Helvetica,sans-serif}button,input,textarea{font:inherit}a{color:inherit;text-decoration:none}.shell{min-height:100vh}.nav{background:var(--dark);color:#fff;justify-content:space-between;align-items:center;gap:20px;height:68px;padding:0 max(24px,50vw - 590px);display:flex}.brand{letter-spacing:.08em;font-weight:900}.brand b{color:#ed3b46}.navlinks{color:#d9e2ec;gap:20px;font-size:14px;font-weight:700;display:flex}.navlinks a:hover{color:#fff}.hero{color:#fff;background:linear-gradient(120deg,#071827,#123a51 60%,#a71928);padding:74px 24px}.hero-inner,.page{width:min(1180px,100% - 40px);margin:auto}.hero h1{max-width:700px;margin:0 0 16px;font-size:clamp(36px,6vw,66px);line-height:1.02}.hero p{color:#d9e2ec;max-width:570px;font-size:18px;line-height:1.6}.button{background:var(--red);color:#fff;cursor:pointer;border:0;border-radius:8px;justify-content:center;align-items:center;padding:12px 17px;font-weight:800;display:inline-flex}.button.secondary{color:var(--ink);border:1px solid var(--line);background:#fff}.button:disabled{opacity:.55;cursor:not-allowed}.page{padding:34px 0 64px}.heading{justify-content:space-between;align-items:end;gap:16px;margin-bottom:20px;display:flex}.heading h1,.heading h2{margin:0}.heading p{color:var(--muted);margin:7px 0 0}.grid{grid-template-columns:repeat(auto-fill,minmax(245px,1fr));gap:18px;display:grid}.card{background:var(--paper);border:1px solid var(--line);border-radius:12px;overflow:hidden;box-shadow:0 3px 10px #102a4310}.cover{object-fit:cover;background:linear-gradient(135deg,#173f5f,#bd202c);width:100%;height:150px}.card-body{padding:16px}.tag{color:var(--red);text-transform:uppercase;font-size:12px;font-weight:800}.card h3{margin:8px 0;font-size:19px}.card p{color:var(--muted);min-height:40px;font-size:14px}.card-foot{justify-content:space-between;align-items:center;margin-top:15px;font-weight:800;display:flex}.detail{grid-template-columns:minmax(0,1.55fr) 350px;gap:24px;display:grid}.panel{border:1px solid var(--line);background:#fff;border-radius:12px;padding:22px}.panel h1{margin-top:0}.lesson{border-top:1px solid var(--line);align-items:center;gap:12px;padding:13px 0;display:flex}.lesson:first-child{border-top:0}.lesson small{color:var(--muted)}.lesson .grow{flex:1}.progress{background:#e8eef3;border-radius:6px;height:7px;overflow:hidden}.progress>span{background:var(--red);height:100%;display:block}.player{aspect-ratio:16/9;background:#071827;border-radius:11px;overflow:hidden}.player video,.player iframe{border:0;width:100%;height:100%}.comments textarea{border:1px solid var(--line);border-radius:8px;width:100%;min-height:90px;padding:10px}.comment{border-top:1px solid var(--line);padding:12px 0}.comment small{color:var(--muted)}.notice{color:#6b4f00;background:#fff3cd;border-radius:8px;margin:12px 0;padding:15px}.empty{text-align:center;color:var(--muted);border:1px dashed var(--line);background:#fff;border-radius:12px;padding:36px}.text-button{color:var(--red);cursor:pointer;background:0 0;border:0;padding:0;font-weight:700}.reply{border-left:3px solid var(--line);background:#f8fafc;margin:12px 0 0 18px;padding:12px}.stats{z-index:1;border:1px solid var(--line);background:#fff;border-radius:12px;grid-template-columns:repeat(3,1fr);width:min(1180px,100% - 40px);margin:-25px auto 0;display:grid;position:relative;box-shadow:0 7px 22px #102a431a}.stats div{text-align:center;border-right:1px solid var(--line);padding:18px 24px}.stats div:last-child{border-right:0}.stats strong,.stats span{display:block}.stats strong{font-size:24px}.stats span{color:var(--muted);margin-top:3px;font-size:13px}.feedback{margin-top:48px}.feedback h2{margin-bottom:16px}@media (max-width:760px){.nav{padding:0 16px}.navlinks{gap:10px;font-size:12px}.hero{padding:48px 20px}.hero-inner,.page{width:min(100% - 28px,1180px)}.detail{grid-template-columns:1fr}.heading{flex-direction:column;align-items:start}}