/* ==========================================
   Main CSS - Global Styles & CSS Variables
   ========================================== */

/* CSS Custom Properties */
:root {
    /* Color Palette - Dark Theme */
    --color-bg-primary: #0a0a0f;
    --color-bg-secondary: #12121a;
    --color-bg-tertiary: #1a1a2e;
    --color-bg-card: rgba(26, 26, 46, 0.7);
    --color-bg-card-hover: rgba(40, 40, 70, 0.8);
    
    /* Accent Colors */
    --color-primary: #7c3aed;
    --color-primary-light: #a78bfa;
    --color-primary-dark: #5b21b6;
    --color-secondary: #4f46e5;
    --color-accent: #06b6d4;
    --color-accent-pink: #ec4899;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    --gradient-accent: linear-gradient(135deg, var(--color-accent) 0%, var(--color-primary) 100%);
    --gradient-glow: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-accent-pink) 100%);
    
    /* Text Colors */
    --color-text-primary: #f8fafc;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'Fira Code', 'Consolas', monospace;
    
    /* Font Sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;
    --text-6xl: 3.75rem;
    
    /* Font Weights */
    --font-light: 300;
    --font-regular: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;
    
    /* 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;
    --space-24: 6rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Shadows */
    --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 -2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(124, 58, 237, 0.4), 0 0 40px rgba(124, 58, 237, 0.2);
    --shadow-glow-accent: 0 0 20px rgba(6, 182, 212, 0.4), 0 0 40px rgba(6, 182, 212, 0.2);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    --transition-slower: 500ms ease;
    
    /* Z-index layers */
    --z-base: 1;
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-modal: 1000;
    --z-tooltip: 1100;
}

/* Light theme variant (for theme toggle demo) */
[data-theme="light"] {
    --color-bg-primary: #f8fafc;
    --color-bg-secondary: #f1f5f9;
    --color-bg-tertiary: #e2e8f0;
    --color-bg-card: rgba(255, 255, 255, 0.9);
    --color-bg-card-hover: rgba(241, 245, 249, 0.95);
    --color-text-primary: #0f172a;
    --color-text-secondary: #475569;
    --color-text-muted: #64748b;
    --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 -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
}

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

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(--text-base);
    font-weight: var(--font-regular);
    line-height: 1.6;
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    overflow-x: hidden;
}

/* Prevent scroll when modal is open */
body.modal-open {
    overflow: hidden;
}

/* Focus styles for accessibility */
:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

:focus:not(:focus-visible) {
    outline: none;
}

:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Selection styling */
::selection {
    background-color: var(--color-primary);
    color: var(--color-text-primary);
}

/* Skip link for accessibility */
.skip-link {
    position: fixed;
    top: -100%;
    left: var(--space-4);
    z-index: var(--z-tooltip);
    padding: var(--space-3) var(--space-6);
    background: var(--gradient-primary);
    color: var(--color-text-primary);
    text-decoration: none;
    font-weight: var(--font-semibold);
    border-radius: var(--radius-md);
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: var(--space-4);
}

/* Visually hidden (for screen readers) */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Hidden utility */
.hidden {
    display: none !important;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-bold);
    line-height: 1.2;
    color: var(--color-text-primary);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-4);
}

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

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

/* Code styling */
code, pre {
    font-family: var(--font-mono);
    font-size: var(--text-sm);
}

pre {
    background: var(--color-bg-secondary);
    padding: var(--space-4);
    border-radius: var(--radius-lg);
    overflow-x: auto;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

code {
    color: var(--color-accent);
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-4) var(--space-8);
    font-family: var(--font-primary);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    text-decoration: none;
    border: none;
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-base);
    min-height: 44px;
    min-width: 44px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn--primary {
    background: var(--gradient-primary);
    color: var(--color-text-primary);
    box-shadow: var(--shadow-lg);
}

.btn--primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

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

.btn--secondary:hover:not(:disabled) {
    background: var(--color-primary);
    box-shadow: var(--shadow-glow);
}

.btn--cta {
    background: var(--color-bg-card);
    color: var(--color-text-primary);
    border: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: var(--space-5) var(--space-8);
}

.btn--cta:hover:not(:disabled) {
    background: var(--color-bg-card-hover);
    border-color: var(--color-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn__icon {
    font-size: var(--text-lg);
    transition: transform var(--transition-fast);
}

.btn:hover .btn__icon {
    transform: translateX(4px);
}

/* Navigation Indicator */
.nav-indicator {
    position: fixed;
    right: var(--space-6);
    top: 50%;
    transform: translateY(-50%);
    z-index: var(--z-sticky);
}

.nav-dots {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    list-style: none;
}

.nav-dot {
    width: 12px;
    height: 12px;
    border-radius: var(--radius-full);
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-base);
    padding: 0;
}

.nav-dot:hover {
    background: rgba(255, 255, 255, 0.4);
    transform: scale(1.2);
}

.nav-dot.active {
    background: var(--color-primary);
    border-color: var(--color-primary-light);
    box-shadow: 0 0 10px var(--color-primary);
}

/* Label utility */
.label {
    display: inline-block;
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-primary-light);
    margin-bottom: var(--space-1);
}

/* Tech tags */
.tech-tag {
    display: inline-block;
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-weight: var(--font-medium);
    background: rgba(124, 58, 237, 0.2);
    color: var(--color-primary-light);
    border-radius: var(--radius-full);
    border: 1px solid rgba(124, 58, 237, 0.3);
}

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

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--color-primary-dark);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-primary);
}