:root {
    /* Shared Design Tokens */
    --font-geist: 'Geist', 'Inter', sans-serif;
    --font-sans: 'Inter', sans-serif;
    --font-serif: 'Playfair Display', serif;

    /* Timing */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    --transition-slow: 0.7s cubic-bezier(0.16, 1, 0.3, 1);

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    --radius-xl: 2rem;
    --radius-full: 9999px;
}

/* ===== LIGHT MODE (Default) ===== */
:root,
[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --bg-tertiary: #E4E4E7;
    --bg-glass: rgba(255, 255, 255, 0.7);
    --bg-glass-border: rgba(0, 0, 0, 0.06);

    --text-primary: #171717;
    --text-secondary: #525252;
    --text-tertiary: #a3a3a3;
    --text-inverse: #ffffff;

    --accent-primary: #171717;
    --accent-secondary: #525252;
    --accent-highlight: #3b82f6;

    --border-subtle: rgba(0, 0, 0, 0.08);
    --border-medium: rgba(0, 0, 0, 0.12);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.05);

    --gradient-text: linear-gradient(to bottom, #111 40%, #444 100%);
    --gradient-card: linear-gradient(to br, #E4E4E7, #f5f5f5);

    --scrollbar-track: #ffffff;
    --scrollbar-thumb: #e5e5e5;
    --scrollbar-thumb-hover: #a3a3a3;
}

/* ===== DARK MODE ===== */
[data-theme="dark"] {
    --bg-primary: #011418;
    --bg-secondary: #020c0e;
    --bg-tertiary: #0a2025;
    --bg-glass: rgba(1, 20, 24, 0.7);
    --bg-glass-border: rgba(34, 211, 238, 0.15);

    --text-primary: #ecfeff;
    --text-secondary: #a5f3fc;
    --text-tertiary: #67e8f9;
    --text-inverse: #011418;

    --accent-primary: #22d3ee;
    --accent-secondary: #06b6d4;
    --accent-highlight: #22d3ee;

    --border-subtle: rgba(34, 211, 238, 0.1);
    --border-medium: rgba(34, 211, 238, 0.2);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 30px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 0 30px -5px rgba(34, 211, 238, 0.3);

    --gradient-text: linear-gradient(to right, #ffffff, #22d3ee);
    --gradient-card: linear-gradient(to br, #0a2025, #011418);

    --scrollbar-track: #011418;
    --scrollbar-thumb: #155e75;
    --scrollbar-thumb-hover: #22d3ee;
}

/* ===== BASE STYLES ===== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-geist);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background-color var(--transition-medium), color var(--transition-medium);
}

::selection {
    background: var(--accent-primary);
    color: var(--text-inverse);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 6px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 3px;
}

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

/* ===== TYPOGRAPHY ===== */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 500;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

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

.serif-text {
    font-family: var(--font-serif);
}

/* ===== LAYOUT UTILITIES ===== */
.container {
    max-width: 80rem;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.section {
    padding: var(--space-3xl) 0;
}

/* ===== GLASS PANEL ===== */
.glass-panel {
    background: var(--bg-glass);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--bg-glass-border);
    box-shadow: var(--shadow-md);
}

/* ===== CARDS ===== */
.card {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-medium);
    overflow: hidden;
}

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

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    border-radius: var(--radius-full);
    font-weight: 500;
    font-size: 0.875rem;
    text-decoration: none;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--accent-primary);
    color: var(--text-inverse);
}

.btn-primary:hover {
    opacity: 0.9;
    transform: scale(1.02);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-subtle);
}

.btn-secondary:hover {
    border-color: var(--border-medium);
    background: var(--bg-secondary);
}

/* ===== LINKS ===== */
a {
    color: inherit;
    text-decoration: none;
}

.link {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.link:hover {
    color: var(--text-primary);
}

/* ===== BADGES ===== */
.badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-sm);
    font-size: 0.625rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: var(--bg-glass);
    border: 1px solid var(--border-subtle);
}

/* ===== STATUS INDICATOR ===== */
.status-dot {
    position: relative;
    width: 0.5rem;
    height: 0.5rem;
}

.status-dot::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 50%;
    background: var(--accent-highlight);
    animation: pulse 2s infinite;
}

.status-dot::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 50%;
    background: var(--accent-highlight);
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
        opacity: 1;
    }

    50% {
        transform: scale(2);
        opacity: 0;
    }
}

/* ===== THEME TOGGLE ===== */
.theme-toggle {
    position: fixed;
    bottom: var(--space-lg);
    right: var(--space-lg);
    z-index: 100;
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    background: var(--bg-glass);
    border: 1px solid var(--border-subtle);
    backdrop-filter: blur(16px);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-md);
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

.theme-toggle svg {
    width: 1.25rem;
    height: 1.25rem;
    color: var(--text-primary);
    transition: transform var(--transition-medium);
}

.theme-toggle:hover svg {
    transform: rotate(15deg);
}

/* Sun icon (shown in dark mode) */
.icon-sun {
    display: none;
}

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

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

/* Moon icon (shown in light mode) */
.icon-moon {
    display: block;
}

/* ===== VISUAL ENGINE CANVAS ===== */
#visual-engine {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    z-index: 0;
    pointer-events: none;
}

#fluid-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 2;
}

[data-theme="dark"] #fluid-canvas {
    opacity: 0;
    pointer-events: none;
}

#gl-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
}

.content-layer {
    position: relative;
    z-index: 10;
}

/* ===== ANIMATIONS ===== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fadeInUp {
    animation: fadeInUp 0.6s ease-out forwards;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

.animate-float {
    animation: float 3s ease-in-out infinite;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
    :root {
        --space-lg: 1rem;
        --space-xl: 1.5rem;
        --space-2xl: 2rem;
        --space-3xl: 3rem;
    }

    .container {
        padding: 0 var(--space-md);
    }
}