:root {
    /* Color Palette */
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --bg-color: #f8fafc;
    --surface-color: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;

    /* Spacing & Layout */
    --container-max-width: 800px;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
    --radius-md: 12px;
    --radius-lg: 24px;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);

    /* Typography */
    --font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

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

body {
    background-color: var(--bg-color);
    font-family: var(--font-family);
    color: var(--text-main);
    line-height: 1.6;
    padding: var(--spacing-md);
}

/* Layout Containers */
.container {
    max-width: var(--container-max-width);
    margin: 40px auto;
    background-color: var(--surface-color);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
}

/* Typography */
h1 {
    color: var(--text-main);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    text-align: center;
}

h2 {
    color: var(--text-main);
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    text-align: center;
}

p {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-lg);
}

/* Buttons & Links */
a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--primary-hover);
}

/* Button-like Links */
.btn, .breadcrumbs a {
    display: inline-block;
    padding: 0.5rem 1rem;
    background-color: var(--surface-color);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.btn:hover, .breadcrumbs a:hover {
    background-color: var(--primary-color);
    color: #fff;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Breadcrumbs Navigation */
.breadcrumbs {
    margin-bottom: var(--spacing-lg);
}

/* Images & Galleries */
img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s ease;
}

img:hover {
    transform: scale(1.02);
}

.gallery {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.gallery img {
    flex: 1 1 300px;
    max-width: 400px;
    object-fit: cover;
}

/* Grid for Index Directory */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
    list-style: none;
    padding: 0;
}

.grid li {
    display: flex;
}

.grid a {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    padding: var(--spacing-md);
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: all 0.2s ease;
    text-align: center;
    color: var(--text-main);
    box-shadow: var(--shadow-sm);
}

.grid a:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.grid img {
    width: 100px;
    height: 100px;
    object-fit: cover;
    border-radius: 50%; /* Circular thumbnails */
    margin-bottom: var(--spacing-md);
    box-shadow: var(--shadow-md);
}

/* Responsive constraints */
@media (max-width: 600px) {
    .container {
        padding: var(--spacing-md);
        margin: 20px auto;
    }
    
    h1 {
        font-size: 2rem;
    }
}