/* =============================================================================
   CSS VARIABLES - LIGHT MODE
   ============================================================================= */
:root {
    --bg-primary: #f8fafc;
    --bg-secondary: #f1f5f9;
    --bg-card: #ffffff;
    --bg-hover: #e2e8f0;

    --primary-color: #0891b2;
    --primary-hover: #0e7490;
    --primary-light: #cffafe;

    --accent-green: #10b981;

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;

    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.10);
    --shadow-hover: 0 12px 40px rgba(0, 0, 0, 0.12);

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

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
}

/* =============================================================================
   DARK MODE
   ============================================================================= */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --bg-hover: #334155;

    --primary-color: #22d3ee;
    --primary-hover: #06b6d4;
    --primary-light: #164e63;

    --accent-green: #34d399;

    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    --border-color: #334155;
    --border-hover: #475569;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
    --shadow-hover: 0 12px 40px rgba(0, 0, 0, 0.6);

    color-scheme: dark;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --bg-primary: #0f172a;
        --bg-secondary: #1e293b;
        --bg-card: #1e293b;
        --bg-hover: #334155;

        --primary-color: #22d3ee;
        --primary-hover: #06b6d4;
        --primary-light: #164e63;

        --accent-green: #34d399;

        --text-primary: #e2e8f0;
        --text-secondary: #94a3b8;
        --text-muted: #64748b;

        --border-color: #334155;
        --border-hover: #475569;

        --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
        --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
        --shadow-hover: 0 12px 40px rgba(0, 0, 0, 0.6);

        color-scheme: dark;
    }
}

/* =============================================================================
   GLOBAL STYLES
   ============================================================================= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', sans-serif;
    background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* =============================================================================
   HEADER
   ============================================================================= */
.header {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-align: center;
}

.header .theme-toggle {
    position: absolute;
    right: 0;
}

.logo {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
}

.brand-text {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.brand-name {
    font-size: 1.25rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-green));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    line-height: 1.2;
}

.tagline {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
    line-height: 1.2;
}

/* =============================================================================
   THEME TOGGLE
   ============================================================================= */
.theme-toggle {
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    transition: all 0.3s ease;
    color: var(--text-secondary);
}

.theme-toggle:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background: var(--bg-hover);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
}

.theme-toggle .sun-icon { display: none; }
.theme-toggle .moon-icon { display: block; }

[data-theme="dark"] .theme-toggle .sun-icon { display: block; }
[data-theme="dark"] .theme-toggle .moon-icon { display: none; }

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .theme-toggle .sun-icon { display: block; }
    :root:not([data-theme="light"]) .theme-toggle .moon-icon { display: none; }
}

/* =============================================================================
   MAIN CONTENT
   ============================================================================= */
.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl) var(--spacing-md);
    max-width: 1000px;
    margin: 0 auto;
    width: 100%;
}

/* =============================================================================
   PRODUCT CARDS
   ============================================================================= */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    width: 100%;
}

.product-card {
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    text-decoration: none;
    color: inherit;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-color);
}

.product-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
    display: block;
}

.product-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.product-description {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    flex: 1;
}

.product-link {
    display: inline-block;
    margin-top: var(--spacing-md);
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    font-size: 0.9rem;
    border-radius: var(--radius-sm);
    transition: all 0.3s ease;
    align-self: center;
}

.product-link:hover,
.product-card:hover .product-link {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

/* =============================================================================
   FOOTER
   ============================================================================= */
.footer {
    text-align: center;
    padding: var(--spacing-lg) var(--spacing-md);
    color: var(--text-muted);
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

/* =============================================================================
   RESPONSIVE
   ============================================================================= */
@media (max-width: 768px) {
    .main {
        padding: var(--spacing-lg) var(--spacing-md);
    }

    .products-grid {
        gap: var(--spacing-md);
    }

    .product-card {
        padding: var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    .brand-name {
        font-size: 1.1rem;
    }

    .tagline {
        display: none;
    }

    .logo {
        width: 32px;
        height: 32px;
    }

    .product-icon {
        font-size: 2.5rem;
    }

    .product-title {
        font-size: 1.1rem;
    }
}