/**
 * Universal Back Button — Spartan Research Station
 * Positioned below nav bars (top: 70px) to prevent overlap with
 * sticky/fixed headers across all 38 pages.
 */

.back-button {
    position: fixed;
    top: 70px;
    left: 16px;
    z-index: 900;

    /* Spartan dark theme — no more dark red */
    background: rgba(10, 22, 40, 0.92);
    color: #FFD700;
    border: 1px solid rgba(255, 215, 0, 0.35);
    padding: 7px 14px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 13px;
    font-weight: 600;
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    text-decoration: none;
    letter-spacing: 0.3px;

    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);

    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
    transition: background 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;

    display: inline-flex;
    align-items: center;
    gap: 6px;

    user-select: none;
    -webkit-user-select: none;
}

.back-button:hover {
    background: rgba(15, 31, 61, 0.96);
    border-color: rgba(255, 215, 0, 0.7);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5), 0 0 12px rgba(255, 215, 0, 0.15);
    color: #FFD700;
    text-decoration: none;
}

.back-button:active {
    transform: translateY(1px);
}

.back-button:focus {
    outline: 2px solid rgba(255, 215, 0, 0.6);
    outline-offset: 2px;
}

@media (max-width: 768px) {
    .back-button {
        top: 70px;
        left: 12px;
        padding: 6px 12px;
        font-size: 12px;
    }
}

@media print {
    .back-button { display: none; }
}