/* CSS Variables & Dark-Modern Theme Setup */
:root {
    --primary: #475569;
    --secondary: #f8fafc;
    --accent: #3b82f6;
    --text: #f5f5f5;
    --bg: #0f0f0f;
    --card-bg: #1a1a1a;
    --card-border: #333333;
}

body {
    background-color: var(--bg);
    color: var(--text);
    margin: 0;
    padding: 0;
    font-family: 'Inter', sans-serif;
}

section {
    padding: 32px 16px;
}

@media (min-width: 768px) {
    section {
        padding: 64px 16px;
    }
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 12px;
}

h1 {
    font-weight: 800;
    font-size: clamp(22px, 5vw, 36px);
}

.text-p {
    font-size: clamp(14px, 4vw, 16px);
}

/* CTA Button Styling */
.btn-cta {
    background-color: var(--accent);
    color: #ffffff;
    font-weight: 700;
    font-size: clamp(16px, 4vw, 18px);
    padding: 16px 32px;
    border-radius: 8px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    box-shadow: 0 4px 14px rgba(59, 130, 246, 0.4);
    width: 100%;
    max-width: 360px;
}

.btn-cta:hover {
    background-color: #2563eb;
    color: #ffffff;
}

/* Accessibility SR-Only class for Radio Input hiding */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Gallery Styles (CSS Only) */
.gallery-main {
    position: relative;
    width: 100%;
    padding-bottom: 100%;
    overflow: hidden;
}

.slide {
    position: absolute;
    inset: 0;
    opacity: 0;
    z-index: 1;
    transition: opacity 0.3s ease-in-out;
}

/* Slide switches via radio inputs */
#img-1:checked ~ .gallery-main .slide-1 {
    opacity: 1;
    z-index: 10;
}

#img-2:checked ~ .gallery-main .slide-2 {
    opacity: 1;
    z-index: 10;
}

#img-3:checked ~ .gallery-main .slide-3 {
    opacity: 1;
    z-index: 10;
}

#img-4:checked ~ .gallery-main .slide-4 {
    opacity: 1;
    z-index: 10;
}

/* Thumbnail Navigation */
.thumbnails {
    display: flex;
    gap: 12px;
    margin-top: 16px;
}

.thumbnails label {
    cursor: pointer;
    border: 2px solid transparent;
    border-radius: 8px;
    overflow: hidden;
    flex: 1;
    aspect-ratio: 1 / 1;
    background-color: var(--card-bg);
    transition: border-color 0.2s ease;
}

.thumbnails label:hover {
    border-color: #666;
}

/* Active Thumbnail Highlight */
#img-1:checked ~ .thumbnails label[for="img-1"],
#img-2:checked ~ .thumbnails label[for="img-2"],
#img-3:checked ~ .thumbnails label[for="img-3"],
#img-4:checked ~ .thumbnails label[for="img-4"] {
    border-color: var(--accent);
}