/* ===================================
   CSS VARIABLES & DESIGN TOKENS
   =================================== */

:root {
    /* Colors - Light Mode */
    --color-primary: hsl(243, 80%, 62%);
    --color-primary-light: hsl(243, 80%, 70%);
    --color-primary-dark: hsl(243, 80%, 52%);
    --color-secondary: hsl(271, 76%, 53%);
    --color-accent: hsl(280, 87%, 65%);
    
    --color-success: hsl(142, 71%, 45%);
    --color-error: hsl(0, 84%, 60%);
    --color-warning: hsl(45, 93%, 47%);
    --color-info: hsl(199, 89%, 48%);
    
    --color-bg-primary: hsl(0, 0%, 100%);
    --color-bg-secondary: hsl(240, 20%, 98%);
    --color-bg-tertiary: hsl(240, 15%, 96%);
    --color-bg-elevated: hsl(0, 0%, 100%);
    
    --color-text-primary: hsl(240, 15%, 15%);
    --color-text-secondary: hsl(240, 10%, 40%);
    --color-text-tertiary: hsl(240, 8%, 60%);
    --color-text-inverse: hsl(0, 0%, 100%);
    
    --color-border: hsl(240, 15%, 90%);
    --color-border-hover: hsl(240, 15%, 80%);
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, hsl(243, 80%, 62%) 0%, hsl(271, 76%, 53%) 100%);
    --gradient-secondary: linear-gradient(135deg, hsl(271, 76%, 53%) 0%, hsl(280, 87%, 65%) 100%);
    --gradient-accent: linear-gradient(135deg, hsl(199, 89%, 48%) 0%, hsl(243, 80%, 62%) 100%);
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;
    
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --font-weight-extrabold: 800;
    
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
    
    /* Layout */
    --container-max-width: 1200px;
    --header-height: 70px;
}

/* Dark Mode Variables */
[data-theme="dark"] {
    --color-bg-primary: hsl(240, 15%, 8%);
    --color-bg-secondary: hsl(240, 15%, 11%);
    --color-bg-tertiary: hsl(240, 15%, 14%);
    --color-bg-elevated: hsl(240, 15%, 12%);
    
    --color-text-primary: hsl(0, 0%, 95%);
    --color-text-secondary: hsl(240, 5%, 70%);
    --color-text-tertiary: hsl(240, 5%, 50%);
    
    --color-border: hsl(240, 15%, 20%);
    --color-border-hover: hsl(240, 15%, 30%);
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6), 0 10px 10px -5px rgba(0, 0, 0, 0.4);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
}

/* ===================================
   RESET & BASE STYLES
   =================================== */

*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    line-height: var(--line-height-normal);
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    transition: background-color var(--transition-base), color var(--transition-base);
    overflow-x: hidden;
}

/* ===================================
   LAYOUT
   =================================== */

.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

@media (max-width: 768px) {
    .container {
        padding: 0 var(--space-4);
    }
}

/* ===================================
   HEADER & NAVIGATION
   =================================== */

.header {
    position: sticky;
    top: 0;
    width: 100%;
    height: var(--header-height);
    background-color: var(--color-bg-elevated);
    border-bottom: 1px solid var(--color-border);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: var(--z-sticky);
    transition: all var(--transition-base);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.nav__logo {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    text-decoration: none;
    color: var(--color-text-primary);
    font-weight: var(--font-weight-bold);
    font-size: var(--font-size-lg);
    transition: transform var(--transition-fast);
}

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

.logo-icon {
    width: 40px;
    height: 40px;
    filter: drop-shadow(0 2px 4px rgba(99, 102, 241, 0.3));
}

.nav__menu {
    display: flex;
    align-items: center;
    gap: var(--space-8);
}

.nav__list {
    display: flex;
    align-items: center;
    gap: var(--space-6);
    list-style: none;
}

.nav__link {
    position: relative;
    padding: var(--space-2) var(--space-3);
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: var(--font-weight-medium);
    font-size: var(--font-size-sm);
    transition: color var(--transition-fast);
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transform: translateX(-50%);
    transition: width var(--transition-base);
}

.nav__link:hover,
.nav__link.active {
    color: var(--color-primary);
}

.nav__link.active::after,
.nav__link:hover::after {
    width: 80%;
}

.theme-toggle {
    position: relative;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
}

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

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

.sun-icon {
    display: block;
}

.moon-icon {
    display: none;
}

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

[data-theme="dark"] .moon-icon {
    display: block;
}

.nav__toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    width: 30px;
    height: 30px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
}

.nav__toggle-line {
    width: 100%;
    height: 3px;
    background: var(--color-text-primary);
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
}

@media (max-width: 768px) {
    .nav__menu {
        position: fixed;
        top: var(--header-height);
        right: -100%;
        width: 280px;
        height: calc(100vh - var(--header-height));
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-4);
        padding: var(--space-8) var(--space-6);
        background: var(--color-bg-elevated);
        border-left: 1px solid var(--color-border);
        box-shadow: var(--shadow-xl);
        transition: right var(--transition-slow);
    }
    
    .nav__menu.active {
        right: 0;
    }
    
    .nav__list {
        flex-direction: column;
        align-items: flex-start;
        width: 100%;
        gap: var(--space-2);
    }
    
    .nav__link {
        width: 100%;
        padding: var(--space-3) var(--space-4);
        border-radius: var(--radius-md);
    }
    
    .nav__link:hover {
        background: var(--color-bg-secondary);
    }
    
    .nav__toggle {
        display: flex;
    }
}

/* ===================================
   HERO SECTION
   =================================== */

.hero {
    padding: var(--space-20) 0 var(--space-16);
    background: linear-gradient(180deg, var(--color-bg-secondary) 0%, var(--color-bg-primary) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.1) 0%, transparent 70%);
    border-radius: 50%;
    animation: float 20s ease-in-out infinite;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.1) 0%, transparent 70%);
    border-radius: 50%;
    animation: float 15s ease-in-out infinite reverse;
}

.hero__content {
    position: relative;
    z-index: 1;
    text-align: center;
}

.hero__title {
    font-size: var(--font-size-5xl);
    font-weight: var(--font-weight-extrabold);
    line-height: var(--line-height-tight);
    margin-bottom: var(--space-6);
    color: var(--color-text-primary);
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero__description {
    max-width: 700px;
    margin: 0 auto var(--space-12);
    font-size: var(--font-size-xl);
    line-height: var(--line-height-relaxed);
    color: var(--color-text-secondary);
}

.hero__stats {
    display: flex;
    justify-content: center;
    gap: var(--space-8);
    flex-wrap: wrap;
}

.stat-card {
    padding: var(--space-6);
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    min-width: 150px;
}

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

.stat-card__value {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-extrabold);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--space-2);
}

.stat-card__label {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
    font-weight: var(--font-weight-medium);
}

@media (max-width: 768px) {
    .hero {
        padding: var(--space-12) 0 var(--space-10);
    }
    
    .hero__title {
        font-size: var(--font-size-3xl);
    }
    
    .hero__description {
        font-size: var(--font-size-base);
    }
    
    .hero__stats {
        gap: var(--space-4);
    }
    
    .stat-card {
        min-width: 120px;
        padding: var(--space-4);
    }
}

/* ===================================
   MAIN CONTENT
   =================================== */

.main {
    padding: var(--space-16) 0;
}

/* ===================================
   UTILITY CLASSES
   =================================== */

.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Smooth scrolling for anchor links */
html {
    scroll-padding-top: calc(var(--header-height) + var(--space-4));
}