/* STT Public Styles */
.stt-container {
    max-width: 1000px;
    margin: 0 auto;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

.stt-filter-wrap {
    background: #f1f5f9;
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.stt-select {
    padding: 8px 12px;
    border: 1px solid #cbd5e1;
    border-radius: 6px;
    font-size: 16px;
    min-width: 200px;
    max-width: 100%;
}

.stt-title {
    text-align: center;
    color: #1e293b;
    margin-bottom: 20px;
}

.stt-table-responsive {
    overflow-x: auto;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

.stt-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 600px;
}

.stt-table th, .stt-table td {
    border: 1px solid #e2e8f0;
    padding: 12px;
    text-align: center;
}

.stt-table th {
    background-color: #3b82f6;
    color: #ffffff;
    font-weight: 600;
}

.stt-th-period, .stt-td-period {
    background-color: #f8fafc;
    font-weight: 600;
    color: #475569;
    width: 60px;
}

.stt-td-session {
    background-color: #eff6ff;
    font-weight: bold;
    color: #1d4ed8;
    width: 60px;
    writing-mode: unset;
}

.stt-btn-download {
    background-color: #10b981;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: background-color 0.2s;
}

.stt-btn-download:hover {
    background-color: #059669;
}

.stt-btn-download:disabled {
    background-color: #9ca3af;
    cursor: not-allowed;
}

.stt-subject {
    font-weight: bold;
    color: #0f172a;
    font-size: 15px;
    margin-bottom: 4px;
}

.stt-teacher {
    font-size: 13px;
    color: #64748b;
}

.stt-empty {
    color: #cbd5e1;
}

.stt-empty-state {
    text-align: center;
    padding: 30px;
    color: #64748b;
    background: #f8fafc;
    border-radius: 8px;
    border: 1px dashed #cbd5e1;
}

/* Mobile optimizations */
@media (max-width: 768px) {
    .stt-filter-wrap {
        flex-direction: column;
        align-items: flex-start;
    }
    .stt-select {
        width: 100%;
    }
}