/* ===================================
   CSS RESET & BASE STYLES
   =================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* ===================================
   CSS VARIABLES - LIGHT & DARK THEMES
   =================================== */
:root {
    /* Light Theme Colors */
    --bg-primary: #FAFAF9;
    --bg-secondary: #FFFFFF;
    --bg-tertiary: #F5F5F4;
    --text-primary: #1C1917;
    --text-secondary: #57534E;
    --text-tertiary: #78716C;
    --accent-primary: #138A7D;
    --accent-hover: #0F6B61;
    --border-color: #E7E5E4;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-serif: 'Crimson Pro', 'Georgia', serif;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', sans-serif;
    
    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
}

[data-theme="dark"] {
    --bg-primary: #1C1917;
    --bg-secondary: #292524;
    --bg-tertiary: #44403C;
    --text-primary: #FAFAF9;
    --text-secondary: #D6D3D1;
    --text-tertiary: #A8A29E;
    --accent-primary: #2DD4BF;
    --accent-hover: #5EEAD4;
    --border-color: #44403C;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.5);
}

/* ===================================
   TYPOGRAPHY
   =================================== */
@import url('https://fonts.googleapis.com/css2?family=Crimson+Pro:wght@400;600;700&display=swap');

body {
    font-family: var(--font-sans);
    font-size: 1.0625rem;
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: background-color var(--transition-base), color var(--transition-base);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
    margin-bottom: var(--space-md);
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.75rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2rem); }

p {
    margin-bottom: var(--space-md);
    color: var(--text-secondary);
}

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

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

/* ===================================
   LAYOUT UTILITIES
   =================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* ===================================
   HEADER & NAVIGATION
   =================================== */
.site-header {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--space-md) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    background-color: rgba(250, 250, 249, 0.95);
    transition: all var(--transition-base);
}

[data-theme="dark"] .site-header {
    background-color: rgba(41, 37, 36, 0.95);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    transition: transform var(--transition-fast);
}

.logo:hover {
    transform: translateY(-2px);
}

.logo svg {
    width: 28px;
    height: 28px;
    stroke: var(--accent-primary);
}

.main-nav {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-weight: 500;
    color: var(--text-secondary);
    padding: var(--space-xs) 0;
    border-bottom: 2px solid transparent;
    transition: all var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
}

.nav-link svg {
    width: 18px;
    height: 18px;
}

.theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.theme-toggle:hover {
    border-color: var(--accent-primary);
    transform: rotate(15deg);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    stroke: var(--text-primary);
    position: absolute;
    transition: all var(--transition-base);
}

.theme-toggle .sun-icon {
    opacity: 0;
    transform: rotate(90deg) scale(0);
}

[data-theme="dark"] .theme-toggle .moon-icon {
    opacity: 0;
    transform: rotate(-90deg) scale(0);
}

[data-theme="dark"] .theme-toggle .sun-icon {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

/* ===================================
   HERO SECTION
   =================================== */
.hero {
    padding: var(--space-2xl) 0;
    text-align: center;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    border-bottom: 1px solid var(--border-color);
}

.hero-title {
    font-size: clamp(3rem, 8vw, 5rem);
    margin-bottom: var(--space-sm);
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    color: var(--text-secondary);
    font-weight: 400;
}

/* ===================================
   INTRO SECTION
   =================================== */
.intro {
    padding: var(--space-2xl) 0;
    background-color: var(--bg-secondary);
}

.intro-text {
    font-size: 1.25rem;
    line-height: 1.8;
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    color: var(--text-secondary);
}

/* ===================================
   ARTICLES SECTION
   =================================== */
.articles {
    padding: var(--space-2xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--space-xl);
    font-size: clamp(2rem, 4vw, 2.5rem);
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-xl);
}

.article-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: var(--space-lg);
    transition: all var(--transition-base);
    display: flex;
    flex-direction: column;
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-primary);
}

.article-meta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.reading-time {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.reading-time svg {
    width: 16px;
    height: 16px;
}

.article-title {
    font-size: 1.5rem;
    margin-bottom: var(--space-md);
    line-height: 1.3;
}

.article-title a {
    color: var(--text-primary);
    transition: color var(--transition-fast);
}

.article-title a:hover {
    color: var(--accent-primary);
}

.article-excerpt {
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
    flex-grow: 1;
}

.read-more {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    font-weight: 600;
    color: var(--accent-primary);
    transition: all var(--transition-fast);
}

.read-more:hover {
    gap: var(--space-sm);
}

.read-more svg {
    width: 18px;
    height: 18px;
}

/* ===================================
   PAGE CONTENT (ABOUT PAGE)
   =================================== */
.page-content {
    padding: var(--space-2xl) 0;
}

.page-header {
    text-align: center;
    margin-bottom: var(--space-xl);
    padding-bottom: var(--space-lg);
    border-bottom: 2px solid var(--border-color);
}

.page-body {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.125rem;
    line-height: 1.8;
}

.page-body p {
    margin-bottom: var(--space-lg);
}

/* ===================================
   ARTICLE CONTENT (ARTICLE PAGES)
   =================================== */
.article-content {
    padding: var(--space-2xl) 0;
}

.article-header {
    max-width: 800px;
    margin: 0 auto var(--space-xl);
    text-align: center;
}

.article-header .article-meta {
    justify-content: center;
    margin-bottom: var(--space-lg);
}

.article-lead {
    font-size: 1.375rem;
    line-height: 1.6;
    color: var(--text-secondary);
    font-weight: 400;
}

.article-body {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.125rem;
    line-height: 1.8;
}

.article-body p {
    margin-bottom: var(--space-lg);
}

.article-footer {
    max-width: 800px;
    margin: var(--space-xl) auto 0;
    padding-top: var(--space-xl);
    border-top: 2px solid var(--border-color);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    font-weight: 600;
    color: var(--accent-primary);
    transition: all var(--transition-fast);
}

.back-link:hover {
    gap: var(--space-sm);
}

.back-link svg {
    width: 18px;
    height: 18px;
}

/* ===================================
   FOOTER
   =================================== */
.site-footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: var(--space-2xl) 0 var(--space-lg);
    margin-top: var(--space-2xl);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--space-xl);
    gap: var(--space-xl);
}

.footer-brand .logo {
    margin-bottom: var(--space-sm);
}

.footer-brand p {
    color: var(--text-tertiary);
    margin: 0;
}

.footer-links {
    display: flex;
    gap: var(--space-lg);
}

.footer-links a {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    text-align: center;
    padding-top: var(--space-lg);
    border-top: 1px solid var(--border-color);
}

.footer-bottom p {
    color: var(--text-tertiary);
    font-size: 0.875rem;
    margin: 0;
}

/* ===================================
   RESPONSIVE DESIGN
   =================================== */
@media (max-width: 768px) {
    .main-nav {
        gap: var(--space-md);
    }
    
    .nav-link span {
        display: none;
    }
    
    .hero {
        padding: var(--space-xl) 0;
    }
    
    .articles-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-md);
    }
    
    .header-content {
        flex-wrap: wrap;
    }
    
    .main-nav {
        gap: var(--space-sm);
    }
}

/* ===================================
   ANIMATIONS & MICRO-INTERACTIONS
   =================================== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.article-card {
    animation: fadeIn 0.6s ease backwards;
}

.article-card:nth-child(1) { animation-delay: 0.1s; }
.article-card:nth-child(2) { animation-delay: 0.2s; }
.article-card:nth-child(3) { animation-delay: 0.3s; }

/* ===================================
   PRINT STYLES
   =================================== */
@media print {
    .site-header,
    .site-footer,
    .theme-toggle,
    .read-more,
    .back-link {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
}