*{box-sizing:border-box}
body{margin:0;font-family:Arial,sans-serif;background:#f3f4f6;color:#1f2937}
main{width:min(960px,92%);margin:40px auto;background:#fff;border:1px solid #9ca3af;padding:30px;box-shadow:0 12px 30px #00000018}
header{text-align:center;margin-bottom:28px}
h1{margin:0 0 8px;font-size:30px}
header p{margin:0;color:#6b7280}
.subjects{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.subject{position:relative;display:flex;flex-direction:column;align-items:center;gap:12px;padding:14px;text-decoration:none;color:#1d4ed8;border:1px solid #d1d5db;border-radius:8px;background:#fff;transition:.2s}
.subject:hover{transform:translateY(-5px);box-shadow:0 10px 22px #00000024}
.subject span{font-weight:700;font-size:18px;text-decoration:underline}
.subject img{width:100%;height:250px;object-fit:cover}
.subject small{position:absolute;right:10px;top:10px;background:#6b7280;color:#fff;padding:4px 7px;border-radius:12px;text-decoration:none}
.subject.disabled{cursor:not-allowed;filter:grayscale(1);opacity:.65}
.subject.disabled:hover{transform:none;box-shadow:none}
.back{text-align:center;margin:26px 0 0}
.back a{color:#1d4ed8}
@media(max-width:760px){.subjects{grid-template-columns:repeat(2,1fr)}.subject img{height:220px}}
@media(max-width:430px){.subjects{grid-template-columns:1fr}}