:root {
    /* Default Dark Theme (User Request) */
    --bg-primary: #020617;
    --bg-surface: #0f172a;
    --bg-elevated: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-tertiary: #64748b;
    --border-color: #1e293b;

    --accent-color: #818cf8;
    --accent-hover: #a5b4fc;
    --accent-glow: rgba(129, 140, 248, 0.5);
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #ec4899 100%);

    --success: #34d399;
    --warning: #fbbf24;
    --error: #f87171;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 25px rgba(99, 102, 241, 0.35);

    --radius: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-main: 'Inter', sans-serif;
}

[data-theme="light"] {
    /* Premium Light Theme */
    --bg-primary: #f1f5f9;
    --bg-surface: #ffffff;
    --bg-elevated: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --text-tertiary: #94a3b8;
    --border-color: #e2e8f0;

    --accent-color: #6366f1;
    --accent-hover: #4f46e5;
    --accent-glow: rgba(99, 102, 241, 0.4);
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);

    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow: 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-glow: 0 0 20px rgba(99, 102, 241, 0.25);
}

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

body {
    font-family: var(--font-main);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: 3.5rem;
    letter-spacing: -0.02em;
}

h2 {
    font-size: 2.5rem;
    letter-spacing: -0.01em;
}

h3 {
    font-size: 1.5rem;
}

p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    gap: 8px;
}

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 0 20px var(--accent-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px var(--accent-glow);
}

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

.btn-secondary:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
}

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(var(--bg-primary), 0.8);
    /* Falls back mostly to color, checking if I need RGB vars for alpha */
    /* Since I use hex, I'll use backdrop-filter */
    background: var(--bg-surface);
    /* Fallback */
}

@supports (backdrop-filter: blur(10px)) {
    header {
        background: transparent;
        backdrop-filter: blur(12px);
    }
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.logo span.material-icons {
    font-size: 32px;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    font-weight: 500;
    color: var(--text-secondary);
}

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

.nav-controls {
    display: flex;
    align-items: center;
    gap: 16px;
}

/* Hero Section */
.hero {
    padding: 160px 0 100px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -20%;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: var(--accent-color);
    opacity: 0.15;
    filter: blur(100px);
    border-radius: 50%;
    z-index: -1;
}

.hero h1 {
    margin-bottom: 24px;
    background: linear-gradient(to right, var(--text-primary) 20%, var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.hero-subtitle {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto 40px;
}

.hero-image {
    margin-top: 60px;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-elevated);
    overflow: hidden;
    position: relative;
    background: var(--bg-surface);
    aspect-ratio: 16/9;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-image img {
    width: 100%;
    height: auto;
    display: block;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
}

/* Features Section */
.features {
    padding: 100px 0;
    background: var(--bg-surface);
}

.section-header {
    text-align: center;
    margin-bottom: 80px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.feature-card {
    padding: 32px;
    border-radius: 24px;
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-color);
    box-shadow: var(--shadow-glow);
}

.feature-icon {
    width: 56px;
    height: 56px;
    border-radius: 16px;
    background: rgba(99, 102, 241, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    color: var(--accent-color);
}

.feature-card h3 {
    margin-bottom: 12px;
}

.feature-screenshot {
    margin-top: 24px;
    border-radius: 12px;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    height: 180px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    position: relative;
}

.feature-screenshot img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.placeholder-text {
    color: var(--text-tertiary);
    font-size: 0.9rem;
    font-style: italic;
}

/* Pricing/CTA Section */
.pricing {
    padding: 100px 0;
    text-align: center;
}

.pricing-card {
    max-width: 500px;
    margin: 0 auto;
    padding: 40px;
    border-radius: 30px;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.pricing-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 6px;
    background: var(--accent-gradient);
}

.cta-box {
    background: var(--accent-gradient);
    border-radius: 24px;
    padding: 60px;
    text-align: center;
    color: white;
}

.cta-box h2 {
    color: white;
}

.cta-box p {
    color: rgba(255, 255, 255, 0.9);
}

/* Footer */
footer {
    padding: 60px 0;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 24px;
}

.copyright {
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

/* Controls (Lang & Theme) */
.icon-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
}

.icon-btn:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
    background: rgba(99, 102, 241, 0.1);
}

.lang-selector {
    position: relative;
}

.lang-menu {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 8px;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 8px;
    width: 150px;
    box-shadow: var(--shadow-lg);
    display: none;
    z-index: 1001;
}

.lang-menu.show {
    display: block;
}

.lang-menu button {
    display: block;
    width: 100%;
    text-align: left;
    padding: 8px 12px;
    background: transparent;
    border: none;
    color: var(--text-primary);
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.lang-menu button:hover {
    background: var(--bg-primary);
}

/* Responsive */
@media (max-width: 768px) {
    h1 {
        font-size: 2.5rem;
    }

    h2 {
        font-size: 2rem;
    }

    .nav-links {
        display: none;
        /* simple mobile hide for now */
    }

    .hero {
        padding: 120px 0 60px;
    }

    .hero-buttons {
        flex-direction: column;
        padding: 0 20px;
    }
}