:root {
    --bg: #050816;
    --bg-alt: #0b1020;
    --accent: #ffd700;
    --accent-soft: rgba(255, 215, 0, 0.12);
    --text: #f5f5f5;
    --muted: #a5a5b8;
}

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: radial-gradient(circle at top, #171c3a 0, #050816 55%, #01010a 100%);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    align-items: stretch;
    justify-content: center;
}

.page {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.top-bar {
    display: flex;
    flex-direction: column;
    gap: 4px;
    justify-content: center;
    align-items: flex-start;
}

.logo {
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    font-size: 0.9rem;
    color: var(--accent);
}

.logo span {
    color: var(--text);
}

.tagline {
    font-size: 0.85rem;
    color: var(--muted);
}

.viewer {
    background: linear-gradient(135deg, var(--bg-alt), #050816);
    border-radius: 18px;
    box-shadow: 0 18px 45px rgba(0, 0, 0, 0.6);
    padding: 16px;
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 8px;
    align-items: center;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.slide-frame {
    background: radial-gradient(circle at top, rgba(255, 255, 255, 0.08), transparent 55%);
    border-radius: 14px;
    padding: 10px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    overflow: hidden;
    max-height: 70vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.slide-frame img {
    display: block;
    width: 100%;
    height: auto;
    max-height: 65vh;
    object-fit: contain;
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.75);
}

.nav-button {
    background: transparent;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.18);
    color: var(--text);
    font-size: 1.8rem;
    width: 40px;
    height: 40px;
    cursor: pointer;
    transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s ease, border-color 0.12s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.nav-button:hover:not(:disabled) {
    background: var(--accent-soft);
    transform: translateY(-1px);
    box-shadow: 0 6px 14px rgba(0, 0, 0, 0.45);
    border-color: rgba(255, 215, 0, 0.6);
}

.nav-button:disabled {
    opacity: 0.3;
    cursor: default;
}

.indicator {
    text-align: center;
    font-size: 0.85rem;
    color: var(--muted);
}

.footer {
    margin-top: 4px;
    text-align: center;
    font-size: 0.75rem;
    color: var(--muted);
    opacity: 0.85;
}

/* Mobile tweaks */
@media (max-width: 640px) {
    .viewer {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto auto;
    }

    .nav-button.prev,
    .nav-button.next {
        width: 100%;
        font-size: 1.3rem;
        margin-top: 4px;
    }

    .nav-button.prev {
        order: 2;
    }

    .nav-button.next {
        order: 3;
    }

    .slide-frame {
        order: 1;
        max-height: 60vh;
    }
}