/* ==========================================================================
   AI Data Governance - Stylesheet
   Version: 1.0.0
   ========================================================================== */

/* ==========================================================================
   1. CSS Variables (Design Tokens)
   ========================================================================== */
:root {
    /* Colors */
    --color-primary-dark: #1a365d;
    --color-primary: #2c5282;
    --color-primary-light: #90cdf4;
    --color-accent: #3182ce;
    --color-text: #333;
    --color-text-light: #718096;
    --color-bg-light: #f7fafc;
    --color-bg-alt: #edf2f7;
    --color-white: #ffffff;
    --color-border: #e2e8f0;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-base: 16px;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --line-height: 1.6;
    --line-height-tight: 1.3;

    /* Spacing */
    --container-max: 1200px;
    --container-narrow: 800px;
    --spacing-xs: 10px;
    --spacing-sm: 20px;
    --spacing-md: 40px;
    --spacing-lg: 60px;
    --spacing-xl: 80px;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
}

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

html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
}

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

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

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

h1, h2, h3, h4, h5, h6 {
    line-height: var(--line-height-tight);
    color: var(--color-primary-dark);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }

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

.container-narrow {
    max-width: var(--container-narrow);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.section {
    padding: var(--spacing-lg) 0;
}

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

/* ==========================================================================
   4. Components
   ========================================================================== */

/* 4.1 Navigation */
.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
}

.nav-logo {
    color: var(--color-white);
    font-size: var(--font-size-lg);
    font-weight: 700;
    text-decoration: none;
}

.nav-logo:hover {
    color: var(--color-primary-light);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-md);
    align-items: center;
}

.nav-menu a {
    color: rgba(255, 255, 255, 0.9);
    font-weight: 500;
    padding: 8px 0;
    border-bottom: 2px solid transparent;
    transition: all var(--transition-fast);
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--color-white);
    border-bottom-color: var(--color-primary-light);
}

.nav-cta {
    background: var(--color-primary-light);
    color: var(--color-primary-dark) !important;
    padding: 8px 20px !important;
    border-radius: 4px;
    border-bottom: none !important;
}

.nav-cta:hover {
    background: var(--color-white);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.nav-toggle span {
    display: block;
    width: 25px;
    height: 2px;
    background: var(--color-white);
    transition: var(--transition-fast);
}

/* 4.2 Header (site navigation) */
body > header {
    background: var(--color-primary-dark);
    position: sticky;
    top: 0;
    z-index: 100;
}

/* 4.3 Hero */
.hero {
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
    color: var(--color-white);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.hero h1 {
    color: var(--color-white);
    margin-bottom: var(--spacing-sm);
}

.hero p {
    font-size: var(--font-size-xl);
    opacity: 0.9;
    max-width: 650px;
    margin: 0 auto var(--spacing-md);
}

.hero-cta {
    display: inline-block;
    background: var(--color-white);
    color: var(--color-primary-dark);
    padding: 14px 32px;
    border-radius: 4px;
    font-weight: 600;
    font-size: var(--font-size-lg);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.hero-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    color: var(--color-primary-dark);
}

/* 4.4 Trust Signals */
.trust-bar {
    background: var(--color-bg-alt);
    padding: var(--spacing-md) 0;
    text-align: center;
}

.trust-bar p {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: var(--spacing-xs);
}

.trust-items {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.trust-items span {
    color: var(--color-primary-dark);
    font-weight: 600;
}

/* 4.5 Article Cards */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.article-card {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: var(--spacing-md);
    transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.article-card:hover {
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    transform: translateY(-4px);
}

.article-card-date {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    margin-bottom: var(--spacing-xs);
}

.article-card h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-xs);
}

.article-card h3 a {
    color: var(--color-primary-dark);
}

.article-card h3 a:hover {
    color: var(--color-accent);
}

.article-card p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.article-card-link {
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.article-card-link::after {
    content: '\2192';
}

/* 4.6 Newsletter CTA */
.newsletter {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: var(--color-white);
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.newsletter h2 {
    color: var(--color-white);
    margin-bottom: var(--spacing-xs);
}

.newsletter p {
    opacity: 0.9;
    margin-bottom: var(--spacing-md);
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.newsletter-form {
    display: flex;
    gap: var(--spacing-xs);
    max-width: 450px;
    margin: 0 auto var(--spacing-sm);
}

.newsletter-form input[type="email"] {
    flex: 1;
    padding: 14px 18px;
    border: none;
    border-radius: 4px;
    font-size: var(--font-size-base);
}

.newsletter-form button {
    background: var(--color-primary-light);
    color: var(--color-primary-dark);
    border: none;
    padding: 14px 28px;
    border-radius: 4px;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.newsletter-form button:hover {
    background: var(--color-white);
}

.newsletter-note {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

/* 4.7 Footer */
footer {
    background: var(--color-primary-dark);
    color: var(--color-white);
    padding: var(--spacing-md) 0;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.footer-links {
    display: flex;
    gap: var(--spacing-md);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    font-size: var(--font-size-sm);
}

.footer-links a:hover {
    color: var(--color-primary-light);
}

.footer-copy {
    color: rgba(255, 255, 255, 0.7);
    font-size: var(--font-size-sm);
}

/* 4.8 Page Header */
.page-header {
    background: var(--color-primary-dark);
    color: var(--color-white);
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.page-header h1 {
    color: var(--color-white);
    margin-bottom: var(--spacing-xs);
}

.page-header p {
    opacity: 0.9;
    font-size: var(--font-size-lg);
}

/* 4.9 Contact */
.contact-content {
    padding: var(--spacing-lg) 0;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
}

.contact-info h2 {
    margin-bottom: var(--spacing-sm);
}

.contact-email {
    display: inline-block;
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.contact-form label {
    display: block;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--color-primary-dark);
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: var(--font-size-base);
    font-family: inherit;
    margin-bottom: var(--spacing-sm);
    transition: border-color var(--transition-fast);
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--color-accent);
}

.contact-form button {
    background: var(--color-primary);
    color: var(--color-white);
    border: none;
    padding: 14px 32px;
    border-radius: 4px;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.contact-form button:hover {
    background: var(--color-primary-dark);
}

/* 4.10 About */
.about-content {
    padding: var(--spacing-lg) 0;
}

.about-intro {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    align-items: start;
}

.about-photo {
    width: 200px;
    height: 200px;
    background: var(--color-bg-alt);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
    color: var(--color-primary);
}

.about-bio h2 {
    margin-bottom: var(--spacing-xs);
}

.about-bio .title {
    color: var(--color-text-light);
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-sm);
}

.about-bio p {
    margin-bottom: var(--spacing-sm);
}

.about-section {
    margin-bottom: var(--spacing-lg);
}

.about-section h3 {
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--color-border);
}

/* 4.11 Article Page */
.article-content {
    padding: var(--spacing-lg) 0;
}

.article-meta {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

.article-meta span {
    margin-right: var(--spacing-sm);
}

.article-body {
    font-size: var(--font-size-lg);
    line-height: 1.8;
}

.article-body h2 {
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.article-body h3 {
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.article-body p {
    margin-bottom: var(--spacing-sm);
}

.article-body ul,
.article-body ol {
    margin-bottom: var(--spacing-sm);
    padding-left: var(--spacing-md);
}

.article-body li {
    margin-bottom: var(--spacing-xs);
}

.article-body blockquote {
    border-left: 4px solid var(--color-primary);
    padding-left: var(--spacing-sm);
    margin: var(--spacing-md) 0;
    font-style: italic;
    color: var(--color-text-light);
}

.author-box {
    background: var(--color-bg-light);
    padding: var(--spacing-md);
    border-radius: 8px;
    margin-top: var(--spacing-lg);
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

.author-box-photo {
    width: 80px;
    height: 80px;
    background: var(--color-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-size: 2rem;
    font-weight: 700;
    flex-shrink: 0;
}

.author-box-info h4 {
    margin-bottom: 4px;
}

.author-box-info p {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    margin-bottom: 8px;
}

/* 4.12 Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 4px;
    font-weight: 600;
    text-align: center;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
}

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

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

.btn-outline {
    background: transparent;
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
}

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

/* 4.13 Section Headers */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-md);
}

.section-header h2 {
    margin-bottom: var(--spacing-xs);
}

.section-header p {
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto;
}

.view-all {
    text-align: center;
    margin-top: var(--spacing-md);
}

/* ==========================================================================
   5. Utilities
   ========================================================================== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* ==========================================================================
   6. Responsive
   ========================================================================== */
@media (max-width: 768px) {
    :root {
        --font-size-4xl: 2rem;
        --font-size-3xl: 1.75rem;
        --spacing-lg: 40px;
        --spacing-xl: 60px;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-primary-dark);
        flex-direction: column;
        padding: var(--spacing-sm);
        gap: 0;
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-menu li {
        width: 100%;
    }

    .nav-menu a {
        display: block;
        padding: 12px;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

    .nav-cta {
        text-align: center;
        margin-top: var(--spacing-xs);
    }

    header {
        position: relative;
    }

    .nav {
        position: relative;
    }

    .hero {
        padding: var(--spacing-lg) 0;
    }

    .newsletter-form {
        flex-direction: column;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

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

    .about-intro {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .about-photo {
        margin: 0 auto;
    }

    .author-box {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .trust-items {
        flex-direction: column;
        gap: var(--spacing-xs);
    }

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