/* ===== CSS Variables ===== */
:root {
    --color-bg: #fafafa;
    --color-surface: #ffffff;
    --color-text: #24292f;
    --color-text-secondary: #57606a;
    --color-border: #d0d7de;
    --color-accent: #0969da;
    --color-accent-hover: #0550ae;
    --color-shadow: rgba(0, 0, 0, 0.1);
    --color-placeholder: linear-gradient(135deg, #667eea 0%, #764ba2 100%);

    --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif;
    --font-mono: ui-monospace, SFMono-Regular, 'SF Mono', Menlo, Consolas, 'Liberation Mono', monospace;

    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;

    --border-radius: 8px;
    --transition: 0.2s ease;

    --max-width: 1200px;
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
    :root {
        --color-bg: #0d1117;
        --color-surface: #161b22;
        --color-text: #e6edf3;
        --color-text-secondary: #8b949e;
        --color-border: #30363d;
        --color-accent: #58a6ff;
        --color-accent-hover: #79c0ff;
        --color-shadow: rgba(0, 0, 0, 0.3);
    }
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Layout ===== */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ===== Header ===== */
.header {
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.header__title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.header__subtitle {
    color: var(--color-text-secondary);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-md);
}

.header__github-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition);
}

.header__github-link:hover {
    color: var(--color-accent-hover);
}

.header__github-link svg {
    width: 20px;
    height: 20px;
}

/* ===== Main Content ===== */
.main {
    flex: 1;
    padding: var(--spacing-xl) 0;
}

/* ===== Filters ===== */
.filters {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.search-input,
.sort-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    background-color: var(--color-surface);
    color: var(--color-text);
    font-size: 0.875rem;
    transition: border-color var(--transition);
}

.search-input {
    flex: 1;
    min-width: 200px;
}

.search-input:focus,
.sort-select:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(9, 105, 218, 0.1);
}

.sort-select {
    cursor: pointer;
    min-width: 150px;
}

.last-updated {
    display: flex;
    align-items: center;
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    margin-left: auto;
    padding: var(--spacing-xs) var(--spacing-sm);
}

@media (max-width: 768px) {
    .last-updated {
        order: 3;
        width: 100%;
        margin-left: 0;
        margin-top: var(--spacing-sm);
    }
}

/* ===== Loading ===== */
.loading {
    text-align: center;
    padding: var(--spacing-xxl);
    color: var(--color-text-secondary);
}

.loading__spinner {
    width: 40px;
    height: 40px;
    margin: 0 auto var(--spacing-md);
    border: 3px solid var(--color-border);
    border-top-color: var(--color-accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ===== Error ===== */
.error {
    text-align: center;
    padding: var(--spacing-xl);
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    margin: var(--spacing-xl) 0;
}

.error p {
    color: #cf222e;
}

/* ===== Projects Grid ===== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

/* ===== Project Card ===== */
.project-card {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    overflow: hidden;
    transition: transform var(--transition), box-shadow var(--transition);
}

.project-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--color-shadow);
}

.project-card__image {
    width: 100%;
    aspect-ratio: 16 / 10;
    background: var(--color-placeholder);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    position: relative;
    overflow: hidden;
}

.project-card__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.project-card__image-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-mono);
}

.project-card__content {
    padding: var(--spacing-md);
}

.project-card__header {
    margin-bottom: var(--spacing-sm);
}

.project-card__name {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.project-card__name a {
    color: var(--color-text);
    text-decoration: none;
}

.project-card__name a:hover {
    color: var(--color-accent);
}

.project-card__description {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    line-height: 1.5;
    margin-bottom: var(--spacing-md);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.project-card__meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.project-card__tag {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-text-secondary);
}

.project-card__stats {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.project-card__stat {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.project-card__actions {
    display: flex;
    gap: var(--spacing-sm);
}

.project-card__link {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    font-weight: 500;
    text-decoration: none;
    text-align: center;
    transition: background-color var(--transition), color var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
}

.project-card__link--primary {
    background-color: var(--color-accent);
    color: white;
}

.project-card__link--primary:hover {
    background-color: var(--color-accent-hover);
}

.project-card__link--secondary {
    background-color: var(--color-bg);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.project-card__link--secondary:hover {
    background-color: var(--color-border);
}

/* ===== Footer ===== */
.footer {
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-lg) 0;
    text-align: center;
    color: var(--color-text-secondary);
    font-size: 0.875rem;
}

/* ===== Responsive Design ===== */
@media (max-width: 600px) {
    .header__title {
        font-size: 1.5rem;
    }

    .header__subtitle {
        font-size: 1rem;
    }

    .filters {
        flex-direction: column;
    }

    .search-input,
    .sort-select {
        width: 100%;
    }

    .projects-grid {
        grid-template-columns: 1fr;
    }

    .project-card__actions {
        flex-direction: column;
    }
}

@media (max-width: 1024px) {
    .projects-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ===== Utility Classes ===== */
.hidden {
    display: none !important;
}