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

:root {
    /* Light Mode Colors */
    --primary-color: #0066FF;
    --primary-hover: #0052CC;
    --secondary-color: #00D4FF;
    --success-color: #00C896;
    --background: #FFFFFF;
    --surface: #F8F9FA;
    --text-primary: #1A1A1A;
    --text-secondary: #6C757D;
    --border-color: #E5E7EB;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --header-height: 70px;
}

[data-theme="dark"] {
    --background: #1e1e1e;
    --surface: #2a2a2a;
    --text-primary: #d4d4d4;
    --text-secondary: #a0a0a0;
    --border-color: #404040;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.25);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.3);
}

html {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", 
                 Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 0.3s ease, color 0.3s ease;
}

main {
    flex: 1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Typography */
h1 {
    font-size: 2.5rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h2 {
    font-size: 2rem;
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: 0.875rem;
}

h3 {
    font-size: 1.5rem;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 0.75rem;
}

h4 {
    font-size: 1.25rem;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 0.625rem;
}

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

/* Header Styles */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--background);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.site-header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
}

[data-theme="dark"] .site-header.scrolled {
    background: rgba(10, 10, 10, 0.95);
}

.nav-wrapper {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.logo svg {
    width: 40px;
    height: 40px;
}

.logo-text {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    margin: 0;
    padding: 0;
}

.nav-menu a {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-menu a.active::after {
    content: '';
    position: absolute;
    bottom: -24px;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-color);
    border-radius: 3px 3px 0 0;
}

.dark-mode-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 8px;
    cursor: pointer;
    color: var(--text-primary);
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
}

.dark-mode-toggle:hover {
    background: var(--surface);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    width: 40px;
    height: 40px;
    position: relative;
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    margin: 5px 0;
    transition: all 0.3s ease;
}

/* Hero Section */
.hero {
    padding: calc(var(--header-height) + 60px) 0 60px;
    text-align: center;
    background: linear-gradient(135deg, var(--surface) 0%, var(--background) 100%);
}

.hero h1 {
    color: var(--text-primary);
    margin-bottom: 1.5rem;
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* Content Section */
.content-section {
    padding: 60px 0;
}

.seo-content {
    max-width: 800px;
    margin: 0 auto;
}

.seo-content h2 {
    color: var(--text-primary);
    margin-top: 2rem;
    margin-bottom: 1rem;
}

.seo-content h3 {
    color: var(--text-primary);
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.seo-content p {
    line-height: 1.8;
    margin-bottom: 1.25rem;
}

/* Footer Styles */
.site-footer {
    background: var(--surface);
    border-top: 1px solid var(--border-color);
    padding: 60px 0 30px;
    margin-top: 80px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.footer-section p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.footer-links {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: var(--text-secondary);
    transition: color 0.3s ease;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.hidden {
    display: none !important;
}