:root {
    --color-bg: #f4f6f9;
    --color-surface: #ffffff;
    --color-border: #e0e4ea;
    --color-text: #1b2430;
    --color-text-muted: #5b6472;
    --color-primary: #2f5fda;
    --color-primary-dark: #23459f;
    --color-success: #1f9d55;
    --color-success-bg: #e8f8ee;
    --color-warning: #b6790a;
    --color-warning-bg: #fdf2df;
    --color-danger: #d1373f;
    --color-danger-bg: #fbe9ea;
    --radius: 10px;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.5;
}

.container {
    max-width: 980px;
    margin: 0 auto;
    padding: 0 20px;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.site-header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 20px;
}
.brand {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
    text-decoration: none;
}
.main-nav {
    display: flex;
    align-items: center;
    gap: 14px;
}
.nav-user {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

main.container {
    padding-top: 28px;
    padding-bottom: 60px;
    min-height: 60vh;
}

h1 { font-size: 1.6rem; margin-bottom: 4px; }
h2 { font-size: 1.25rem; }
.subtitle { color: var(--color-text-muted); margin-top: 0; }

.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 18px;
}

.card-list { display: flex; flex-direction: column; gap: 14px; }

.lesson-card {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 16px;
    flex-wrap: wrap;
}
.lesson-info h3 { margin: 0 0 4px; }
.lesson-meta { color: var(--color-text-muted); font-size: 0.9rem; margin: 2px 0; }
.lesson-actions { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }

.badge {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 999px;
    font-size: 0.8rem;
    font-weight: 600;
}
.badge-paid { background: var(--color-success-bg); color: var(--color-success); }
.badge-pending { background: var(--color-warning-bg); color: var(--color-warning); }
.badge-ended { background: var(--color-danger-bg); color: var(--color-danger); }
.badge-muted { background: #eceff3; color: var(--color-text-muted); }

.btn {
    display: inline-block;
    padding: 9px 16px;
    border-radius: 8px;
    border: 1px solid transparent;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    background: var(--color-primary);
    color: #fff;
}
.btn:hover { background: var(--color-primary-dark); text-decoration: none; }
.btn:disabled { background: #b9c1cf; cursor: not-allowed; }
.btn-secondary { background: #eceff3; color: var(--color-text); }
.btn-secondary:hover { background: #dfe3e9; }
.btn-ghost { background: transparent; color: var(--color-text-muted); border: 1px solid var(--color-border); }
.btn-ghost:hover { background: #f1f3f6; }
.btn-danger { background: var(--color-danger); }
.btn-danger:hover { background: #a92c32; }
.btn-success { background: var(--color-success); }
.btn-success:hover { background: #167a41; }
.btn-sm { padding: 5px 10px; font-size: 0.85rem; }

form.inline { display: inline; }

.form-group { margin-bottom: 16px; }
.form-group label { display: block; margin-bottom: 6px; font-weight: 600; font-size: 0.9rem; }
input[type="text"], input[type="email"], input[type="password"], input[type="datetime-local"], input[type="number"], textarea, select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--color-border);
    border-radius: 8px;
    font-size: 0.95rem;
    background: #fff;
    color: var(--color-text);
    font-family: inherit;
}
textarea { resize: vertical; min-height: 80px; }
.form-narrow { max-width: 420px; }
.radio-group { display: flex; gap: 18px; }
.radio-group label { font-weight: 500; display: flex; align-items: center; gap: 6px; }

.flash { padding: 12px 16px; border-radius: 8px; margin-bottom: 18px; font-size: 0.95rem; }
.flash-success { background: var(--color-success-bg); color: var(--color-success); }
.flash-error { background: var(--color-danger-bg); color: var(--color-danger); }
.flash-info { background: #e6edfb; color: var(--color-primary-dark); }

table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 10px 8px; border-bottom: 1px solid var(--color-border); font-size: 0.92rem; }
th { color: var(--color-text-muted); font-weight: 600; }

.empty-state { color: var(--color-text-muted); padding: 24px 0; text-align: center; }

.site-footer {
    border-top: 1px solid var(--color-border);
    padding: 18px 0;
    color: var(--color-text-muted);
    font-size: 0.85rem;
}

.join-status {
    padding: 16px;
    border-radius: var(--radius);
    margin-bottom: 16px;
    font-weight: 600;
}
.join-status.waiting { background: var(--color-warning-bg); color: var(--color-warning); }
.join-status.ready { background: var(--color-success-bg); color: var(--color-success); }
.join-status.blocked { background: var(--color-danger-bg); color: var(--color-danger); }

#jitsi-container {
    width: 100%;
    height: 70vh;
    min-height: 480px;
    border-radius: var(--radius);
    overflow: hidden;
    background: #000;
    margin-top: 10px;
}

.device-test {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 20px;
    margin-top: 10px;
}
.device-test-hint { color: var(--color-text-muted); margin-top: 2px; }
.device-test-body {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-top: 14px;
}
.device-test-preview {
    position: relative;
    width: 360px;
    max-width: 100%;
    aspect-ratio: 4 / 3;
    background: #111;
    border-radius: 8px;
    overflow: hidden;
    flex-shrink: 0;
}
.device-test-preview video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transform: scaleX(-1);
}
.device-test-placeholder {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #cfd6e0;
    font-size: 0.9rem;
    text-align: center;
    padding: 12px;
}
.device-test-controls {
    flex: 1;
    min-width: 240px;
}
.mic-meter {
    width: 100%;
    height: 14px;
    background: #eceff3;
    border-radius: 999px;
    overflow: hidden;
}
.mic-meter-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--color-success), var(--color-primary));
    transition: width 0.08s linear;
}
.calendar-legend {
    display: flex;
    gap: 18px;
    flex-wrap: wrap;
    margin: 10px 0 18px;
    font-size: 0.88rem;
    color: var(--color-text-muted);
}
.legend-item { display: flex; align-items: center; gap: 6px; }
.legend-dot {
    display: inline-block;
    width: 11px;
    height: 11px;
    border-radius: 50%;
}
#calendar .fc-event { cursor: pointer; }

.device-test-error {
    background: var(--color-danger-bg);
    color: var(--color-danger);
    padding: 10px 12px;
    border-radius: 8px;
    margin-bottom: 12px;
    font-size: 0.9rem;
}

.auth-card { max-width: 420px; margin: 40px auto; }

@media (max-width: 640px) {
    .header-inner { flex-direction: column; align-items: flex-start; gap: 10px; }
    .lesson-card { flex-direction: column; }
}