:root {
    /* Color Palette */
    --color-bg-body: #ffffff;
    --color-bg-light: #f8f9fa;
    --color-bg-overlay: rgba(255, 255, 255, 0.9);

    --color-text-primary: #1a1a1a;
    --color-text-secondary: #666666;
    --color-text-light: #999999;

    --color-accent: #3b82f6;
    /* A clean, professional blue */
    --color-accent-dark: #2563eb;
    --color-border: #e5e5e5;

    /* Typography */
    --font-primary: 'Inter', system-ui, -apple-system, sans-serif;
    --size-h1: 3.5rem;
    --size-h2: 2.5rem;
    --size-h3: 1.75rem;
    --size-body: 1rem;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 8rem;

    /* Layout */
    --container-width: 1200px;
    --header-height: 80px;
}

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

body {
    font-family: var(--font-primary);
    color: var(--color-text-primary);
    background-color: var(--color-bg-body);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s ease;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* Layout Utilities */
.container {
    width: 90%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

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

.grid-2 {
    grid-template-columns: repeat(2, 1fr);
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* Header & Navigation */
.site-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    position: sticky;
    top: 0;
    background-color: var(--color-bg-overlay);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--color-border);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: 700;
    font-size: 1.5rem;
    letter-spacing: -0.02em;
}

.main-nav ul {
    display: flex;
    gap: var(--spacing-md);
}

.main-nav a {
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--color-text-secondary);
}

.main-nav a:hover,
.main-nav a.active {
    color: var(--color-text-primary);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 6px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text-primary);
}

/* Footer */
.site-footer {
    padding: var(--spacing-lg) 0;
    background-color: var(--color-bg-light);
    margin-top: var(--spacing-xl);
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    text-align: center;
}

@media (min-width: 768px) {
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
        text-align: left;
    }
}

/* Typography Utilities */
h1 {
    font-size: var(--size-h1);
    line-height: 1.1;
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.03em;
}

h2 {
    font-size: var(--size-h2);
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.02em;
}

h3 {
    font-size: var(--size-h3);
    margin-bottom: var(--spacing-xs);
}

p {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
}

/* Components */
.btn {
    display: inline-block;
    padding: 0.8em 1.6em;
    background-color: var(--color-text-primary);
    color: white;
    border-radius: 4px;
    font-weight: 500;
    transition: transform 0.2s ease, background-color 0.2s ease;
}

.btn:hover {
    transform: translateY(-2px);
    background-color: #000;
}

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--color-text-primary);
    color: var(--color-text-primary);
}

.btn-outline:hover {
    background-color: var(--color-text-primary);
    color: white;
}

/* Responsive */
@media (max-width: 768px) {
    :root {
        --size-h1: 2.5rem;
        --size-h2: 2rem;
    }

    .main-nav {
        display: none;
        /* TODO: Implement mobile menu toggle logic */
    }

    .mobile-menu-toggle {
        display: flex;
    }


    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }

    .hero h1 {
        font-size: 2.5rem;
    }
}

/* Sections */
.section {
    padding: var(--spacing-xl) 0;
}

.section-header {
    margin-bottom: var(--spacing-lg);
    text-align: center;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.section-header h2 {
    color: var(--color-text-primary);
}

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

/* Hero Component */
.hero {
    position: relative;
    padding: var(--spacing-xl) 0;
    min-height: 80vh;
    display: flex;
    align-items: center;
    background-color: var(--color-bg-light);
    overflow: hidden;
}

.hero-content {
    max-width: 600px;
    position: relative;
    z-index: 10;
}

.hero-image {
    position: absolute;
    top: 0;
    right: 0;
    width: 50%;
    height: 100%;
    object-fit: cover;
    z-index: 1;
    opacity: 0.8;
}

/* Cards */
.card {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--color-border);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.05);
}

.card-image {
    height: 250px;
    overflow: hidden;
    background-color: var(--color-bg-light);
}

.card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.card:hover .card-image img {
    transform: scale(1.05);
}

.card-content {
    padding: var(--spacing-md);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.2s ease;
}

.form-control:focus {
    outline: none;
    border-color: var(--color-accent);
}

textarea.form-control {
    resize: vertical;
    min-height: 120px;
}