:root {
    --white: #FFFFFF;
    --onyx: #0A0A0A;
    --slate: #5A5F66;
    --accent: #CADCF5;
    --font-stack: 'Inter', sans-serif;
}

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

body {
    font-family: var(--font-stack);
    color: var(--onyx);
    background-color: var(--white);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

h1, h2 { font-weight: 600; letter-spacing: -0.02em; }
h1 { font-size: 2.5rem; margin-bottom: 0.25rem; }
h2 { font-size: 1.25rem; color: var(--slate); font-weight: 400; }

.bg-white { background-color: var(--white); }
.bg-accent { background-color: var(--accent); }

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 6rem 2rem;
}
.text-center { text-align: center; }
.max-w-sm { max-width: 600px; margin: 0 auto; }

/* Buttons */
.btn {
    display: inline-block;
    margin-top: 1.5rem;
    padding: 0.75rem 2rem;
    background-color: var(--onyx);
    color: var(--white);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 600;
    transition: background-color 0.2s ease;
}
.btn:hover { background-color: var(--slate); }

.btn.sold {
    background-color: transparent;
    color: var(--slate);
    border: 1px solid var(--slate);
    pointer-events: none;
}

/* Gallery Grid */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 3rem;
}

/* Flip Card Mechanics */
.card {
    background-color: transparent;
    aspect-ratio: 1 / 1.414; /* A-series paper ratio */
    perspective: 1000px;
    cursor: pointer;
    width: 100%;
    max-width: calc(60vh / 1.414); /* cap height to 60% of viewport height */
    margin: 0 auto;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
    /* will-change: transform; */
}

/* Desktop hover */
@media (hover: hover) {
    .card:hover .card-inner {
        transform: rotateY(180deg);
    }
}

/* Mobile tap trigger via JS */
.card.is-flipped .card-inner {
    transform: rotateY(180deg);
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
}

.card-front img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    box-shadow: 0 4px 20px rgba(10, 10, 10, 0.08);
}

.card-back {
    background-color: var(--white);
    color: var(--onyx);
    transform: rotateY(180deg);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    box-shadow: inset 0 0 0 1px var(--accent);
}

.card-back h3 { font-size: 1.25rem; margin-bottom: 1rem; }
.card-back p { font-size: 0.875rem; color: var(--slate); margin-bottom: 0.25rem; }
.card-back .status { margin-top: 1rem; font-weight: 600; color: var(--onyx); }

/* Footer */
.flex-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 2rem;
}
.flex-footer nav a {
    color: var(--onyx);
    text-decoration: none;
    margin-left: 1.5rem;
    font-size: 0.875rem;
}
.flex-footer nav a:hover { text-decoration: underline; }

@media (max-width: 600px) {
    .flex-footer { flex-direction: column; gap: 1rem; }
    .flex-footer nav a { margin: 0 0.75rem; }
}