* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: #0b1220;
    color: #e8edf5;
    min-height: 100vh;
}
a { color: #7eb8ff; text-decoration: none; }
a:hover { text-decoration: underline; }
.container {
    max-width: 720px;
    margin: 0 auto;
    padding: 2rem 1.25rem 3rem;
}
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    gap: 1rem;
    flex-wrap: wrap;
}
.badge {
    display: inline-block;
    padding: 0.25rem 0.6rem;
    border-radius: 999px;
    font-size: 0.75rem;
    background: rgba(126, 184, 255, 0.15);
    color: #9ec5ff;
}
.card {
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 1rem;
}
.card h1, .card h2 {
    font-size: 1.35rem;
    margin-bottom: 0.75rem;
}
.muted { color: #9aa8bc; font-size: 0.9rem; }
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    border: none;
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.15s;
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-primary { background: #2f6fed; color: #fff; }
.btn-primary:hover:not(:disabled) { background: #255fd4; }
.btn-danger { background: #c0392b; color: #fff; }
.btn-secondary { background: rgba(255,255,255,0.08); color: #e8edf5; }
.input, .textarea {
    width: 100%;
    padding: 0.85rem 1rem;
    border-radius: 10px;
    border: 1px solid rgba(255,255,255,0.12);
    background: rgba(0,0,0,0.25);
    color: #fff;
    font-size: 1rem;
}
.textarea { min-height: 100px; resize: vertical; font-family: inherit; }
.input:focus, .textarea:focus {
    outline: none;
    border-color: #2f6fed;
}
.field { margin-bottom: 1rem; }
.field label {
    display: block;
    margin-bottom: 0.4rem;
    font-size: 0.85rem;
    color: #9aa8bc;
}
.room-code {
    font-size: 2rem;
    letter-spacing: 0.35em;
    font-weight: 700;
    color: #7eb8ff;
    text-align: center;
    padding: 1rem;
    background: rgba(47, 111, 237, 0.1);
    border-radius: 12px;
    margin: 1rem 0;
}
.status-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    display: inline-block;
    margin-right: 0.4rem;
}
.status-dot.online { background: #2ecc71; }
.status-dot.waiting { background: #f1c40f; }
.status-dot.playing { background: #3498db; animation: pulse 1s infinite; }
@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}
.student-list { list-style: none; }
.student-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid rgba(255,255,255,0.06);
}
.alert {
    padding: 0.75rem 1rem;
    border-radius: 10px;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}
.alert-error { background: rgba(192,57,43,0.2); color: #ffb4aa; }
.alert-success { background: rgba(46,204,113,0.15); color: #9dffbf; }
.alert-info { background: rgba(47,111,237,0.15); color: #9ec5ff; }
.volume-row {
    display: flex;
    align-items: center;
    gap: 1rem;
}
.volume-row input[type=range] { flex: 1; }
.hidden { display: none !important; }
table { width: 100%; border-collapse: collapse; }
th, td {
    text-align: left;
    padding: 0.6rem 0.5rem;
    border-bottom: 1px solid rgba(255,255,255,0.06);
    font-size: 0.9rem;
}
.actions { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-top: 1rem; }