/* ========================================
   CSS Custom Properties (Design Tokens)
   ======================================== */
:root {
    /* Colors */
    --color-background: #000000;
    --color-text-primary: #ffffff;

    /* Typography */
    --font-family-display: 'Inter', sans-serif;
    --font-size-name: 18px;
    --font-weight-regular: 400;

    /* Name positioning */
    --name-margin: 24px;

    /* Photo sizes - scale with viewport */
    --photo-size-small: clamp(120px, 15vw, 220px);
    --photo-size-medium: clamp(200px, 25vw, 400px);
    --photo-size-large: clamp(300px, 35vw, 550px);
    --photo-size-xlarge: clamp(400px, 45vw, 700px);

    /* Z-index layers */
    --z-background: 0;
    --z-photos: 1;
    --z-loader: 100;
}

/* ========================================
   Reset & Base
   ======================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family-display);
    background-color: var(--color-background);
    color: var(--color-text-primary);
    overflow-x: hidden;
    min-height: 100vh;
}

/* ========================================
   Fixed Background Layer
   ======================================== */
.fixed-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    z-index: var(--z-background);
    pointer-events: none;
}

.photographer-name {
    font-family: var(--font-family-display);
    font-size: var(--font-size-name);
    font-weight: var(--font-weight-regular);
    color: var(--color-text-primary);
    margin: var(--name-margin);
    line-height: 1.2;
    letter-spacing: 0;
}

/* ========================================
   Gallery Container
   ======================================== */
.gallery-container {
    position: relative;
    z-index: var(--z-photos);
    min-height: 100vh;
    padding: 0;
}

.gallery {
    position: relative;
    width: 100%;
}

/* ========================================
   Photo Items
   ======================================== */
.photo-item {
    position: absolute;
    will-change: transform;
    transition: opacity 0.6s ease-out;
    transform: translate3d(0, 0, 0);
    backface-visibility: hidden;
}

.photo-item img {
    display: block;
    width: 100%;
    height: auto;
    object-fit: cover;
}

/* Size variants */
.photo-item--small { width: var(--photo-size-small); }
.photo-item--medium { width: var(--photo-size-medium); }
.photo-item--large { width: var(--photo-size-large); }
.photo-item--xlarge { width: var(--photo-size-xlarge); }

/* Loading state */
.photo-item--loading {
    opacity: 0;
}

.photo-item--loaded {
    opacity: 1;
}

/* ========================================
   Loader
   ======================================== */
.loader {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: var(--z-loader);
    display: flex;
    gap: 8px;
    opacity: 1;
    transition: opacity 0.4s ease-out;
}

.loader-dot {
    width: 8px;
    height: 8px;
    background-color: #ffffff;
    border-radius: 50%;
    animation: loader-pulse 1.4s ease-in-out infinite both;
}

.loader-dot:nth-child(1) { animation-delay: -0.32s; }
.loader-dot:nth-child(2) { animation-delay: -0.16s; }
.loader-dot:nth-child(3) { animation-delay: 0s; }

@keyframes loader-pulse {
    0%, 80%, 100% {
        transform: scale(0.6);
        opacity: 0.5;
    }
    40% {
        transform: scale(1);
        opacity: 1;
    }
}

.loader--hidden {
    opacity: 0;
    pointer-events: none;
}

/* ========================================
   Utility Classes
   ======================================== */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ========================================
   Reduced Motion Support
   ======================================== */
@media (prefers-reduced-motion: reduce) {
    .photo-item {
        transform: none !important;
        will-change: auto;
        transition: none;
    }

    .loader-dot {
        animation: none;
        opacity: 1;
    }
}

/* Performance: only animate visible items */
.photo-item[data-visible="false"] {
    will-change: auto;
}

.photo-item[data-visible="true"] {
    will-change: transform;
}

/* ========================================
   Image Protection
   ======================================== */
.photo-item img {
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    -webkit-user-drag: none;
    -khtml-user-drag: none;
    -moz-user-drag: none;
    -o-user-drag: none;
    user-drag: none;
    pointer-events: none;
}

/* Invisible overlay to prevent interaction */
.photo-item::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: transparent;
    pointer-events: auto;
}