:root {
    /* Light mode colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-gradient-start: #f8fafc;
    --bg-gradient-end: #e2e8f0;
    --text-primary: #1a1a1a;
    --text-secondary: #6b7280;
    --text-heading: #1f2937;
    --accent-primary: #667eea;
    --accent-hover: #5a67d8;
    --card-bg: #ffffff;
    --border-color: #e5e7eb;
    --shadow-color: rgba(0, 0, 0, 0.08);
    --overlay-bg: rgba(255, 255, 255, 0.95);
}

[data-theme="dark"] {
    /* Dark mode colors */
    --bg-primary: #000000;
    --bg-secondary: #0a0a0a;
    --bg-gradient-start: #000000;
    --bg-gradient-end: #1a1a1a;
    --text-primary: #ffffff;
    --text-secondary: #d1d5db;
    --text-heading: #ffffff;
    --accent-primary: #fbbf24;
    --accent-hover: #f59e0b;
    --card-bg: #111111;
    --border-color: #333333;
    --shadow-color: rgba(251, 191, 36, 0.1);
    --overlay-bg: rgba(0, 0, 0, 0.95);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.25rem;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--overlay-bg);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-btn {
    background: var(--accent-primary);
    color: var(--bg-primary);
    padding: 0.75rem 1.5rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
}

.nav-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
    color: var(--bg-primary);
    text-decoration: none;
}

/* Theme toggle button */
.theme-toggle {
    background: transparent;
    border: 2px solid var(--accent-primary);
    color: var(--accent-primary);
    padding: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.2s ease;
    margin-right: 1.5rem;
}

.theme-toggle:hover {
    background: var(--accent-primary);
    color: var(--bg-primary);
}

/* Hero Section */
.hero {
    padding: 8rem 0 6rem;
    text-align: center;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 20%, var(--shadow-color) 0%, transparent 50%),
                radial-gradient(circle at 80% 80%, var(--shadow-color) 0%, transparent 50%);
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: clamp(2.5rem, 8vw, 4.5rem);
    font-weight: 800;
    color: var(--text-heading);
    margin-bottom: 1.5rem;
    line-height: 1.1;
}

.hero-subtitle {
    font-size: clamp(1.125rem, 3vw, 1.375rem);
    color: var(--text-secondary);
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-cta {
    margin-bottom: 4rem;
}

.cta-btn {
    background: var(--accent-primary);
    color: var(--bg-primary);
    padding: 1.25rem 2.5rem;
    border-radius: 16px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.125rem;
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px var(--shadow-color);
}

.cta-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px var(--shadow-color);
    color: var(--bg-primary);
    text-decoration: none;
}

/* Stats Section */
.hero-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 4rem;
}

.stat-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 20px;
    box-shadow: 0 4px 20px var(--shadow-color);
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px var(--shadow-color);
}

.stat-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-primary);
    margin-bottom: 0.5rem;
}

.stat-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Features Section */
.features {
    padding: 6rem 0;
    background: var(--bg-primary);
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    color: var(--text-heading);
    margin-bottom: 1rem;
}

.section-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--bg-secondary);
    padding: 2.5rem 2rem;
    border-radius: 20px;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.feature-card:hover {
    background: var(--card-bg);
    border-color: var(--accent-primary);
    transform: translateY(-5px);
    box-shadow: 0 8px 30px var(--shadow-color);
}

.feature-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-hover));
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    color: var(--bg-primary);
    font-size: 1.5rem;
}

.feature-title {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--text-heading);
    margin-bottom: 1rem;
}

.feature-description {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Demo Section */
.demo {
    padding: 6rem 0;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-gradient-end) 100%);
}

.demo-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.demo-content h2 {
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 700;
    color: var(--text-heading);
    margin-bottom: 1.5rem;
}

.demo-content p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.7;
}

.demo-mockup {
    background: var(--card-bg);
    border-radius: 24px;
    padding: 2rem;
    box-shadow: 0 20px 60px var(--shadow-color);
    transform: rotate(2deg);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.demo-mockup:hover {
    transform: rotate(0deg);
}

.mockup-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border-color);
}

.mockup-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-heading);
}

.status-dot {
    width: 12px;
    height: 12px;
    background: var(--accent-primary);
    border-radius: 50%;
}

.mockup-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.mockup-stat {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-hover));
    padding: 1.25rem;
    border-radius: 12px;
    text-align: center;
    color: var(--bg-primary);
}

.mockup-stat-number {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.mockup-stat-label {
    font-size: 0.875rem;
    opacity: 0.9;
}

.progress-preview {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-gradient-end) 100%);
    height: 100px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-primary);
    font-weight: 600;
    position: relative;
    overflow: hidden;
}

.progress-preview::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, var(--shadow-color), transparent);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { left: -100%; }
    100% { left: 100%; }
}

/* CTA Section */
.cta-section {
    padding: 6rem 0;
    background: var(--bg-gradient-end);
    text-align: center;
    color: var(--text-primary);
}

.cta-section h2 {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    margin-bottom: 1rem;
}

.cta-section p {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.signup-form {
    max-width: 500px;
    margin: 0 auto 2rem;
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.email-input {
    flex: 1;
    min-width: 200px;
    padding: 1.25rem 1.5rem;
    border: 2px solid var(--border-color);
    border-radius: 16px;
    background: var(--card-bg);
    color: var(--text-primary);
    font-size: 1rem;
    transition: all 0.2s ease;
}

.email-input:focus {
    outline: none;
    border-color: var(--accent-primary);
    background: var(--card-bg);
}

.email-input::placeholder {
    color: var(--text-secondary);
}

.signup-btn {
    background: var(--accent-primary);
    color: var(--bg-primary);
    padding: 1.25rem 2rem;
    border-radius: 16px;
    border: none;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
    min-width: 100px;
}

.signup-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

.form-note {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.confirmation-message {
    background: var(--shadow-color);
    color: var(--accent-primary);
    padding: 1rem 2rem;
    border-radius: 12px;
    margin-top: 1rem;
    font-weight: 600;
    display: none;
}

/* Footer */
.footer {
    padding: 3rem 0;
    background: var(--bg-secondary);
    text-align: center;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .hero {
        padding: 6rem 0 4rem;
    }

    .nav {
        padding: 0.75rem 0;
    }

    .logo {
        font-size: 1.25rem;
    }

    .nav-btn {
        padding: 0.6rem 1.2rem;
        font-size: 0.9rem;
    }

    .hero-stats {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .demo-container {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
    }

    .demo-mockup {
        transform: none;
    }

    .mockup-stats {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    .signup-form {
        flex-direction: column;
        align-items: stretch;
    }

    .email-input {
        min-width: auto;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .feature-card {
        padding: 2rem 1.5rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .hero {
        padding: 5rem 0 3rem;
    }

    .features,
    .demo,
    .cta-section {
        padding: 4rem 0;
    }

    .stat-card,
    .feature-card {
        padding: 1.5rem;
    }

    .demo-mockup {
        padding: 1.5rem;
    }
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

.fade-in-up-delay-1 {
    animation: fadeInUp 0.6s ease-out 0.2s both;
}

.fade-in-up-delay-2 {
    animation: fadeInUp 0.6s ease-out 0.4s both;
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Focus styles for accessibility */
.nav-btn:focus,
.cta-btn:focus,
.signup-btn:focus,
.email-input:focus {
    outline: 2px solid #667eea;
    outline-offset: 2px;
}