:root {
    --primary: #0369a1;
    --secondary: #e0f2fe;
    --accent: #06b6d4;
    --text: #0c1a27;
    --bg: #f8faff;
}

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

section {
    padding: 32px 16px;
}

@media (min-width: 768px) {
    section {
        padding: 48px 16px;
    }
}

.card {
    border-radius: 20px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
}

h1 {
    font-weight: 800;
    line-height: 1.1;
    font-size: clamp(18px, 4vw, 24px);
}

.btn {
    border-radius: 16px;
    font-weight: 700;
    box-shadow: 0 4px 16px rgba(3, 105, 161, 0.25);
}

.btn:hover {
    box-shadow: 0 6px 20px rgba(3, 105, 161, 0.35);
}

/* Visually hidden for accessible inputs */
.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;
}

/* Pure CSS Gallery */
.gallery-container {
    width: 100%;
}

.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;
}

/* Gallery radio input state controls */
#img-1:checked ~ .gallery-main .slide-1,
#img-2:checked ~ .gallery-main .slide-2,
#img-3:checked ~ .gallery-main .slide-3,
#img-4:checked ~ .gallery-main .slide-4 {
    opacity: 1;
    z-index: 10;
}

#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(--primary);
    box-shadow: 0 0 0 2px rgba(3, 105, 161, 0.2);
}