/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3b82f6;
    --secondary-color: #8b5cf6;
    --accent-color: #06b6d4;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --bg-color: #ffffff;
    --bg-secondary: #f9fafb;
    --border-color: #e5e7eb;
    --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    --text-color: #f9fafb;
    --text-light: #d1d5db;
    --bg-color: #111827;
    --bg-secondary: #1f2937;
    --border-color: #374151;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    transition: var(--transition);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Header and Navigation */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: var(--transition);
}

[data-theme="dark"] .header {
    background: rgba(17, 24, 39, 0.8);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.nav-brand h1 {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.5rem;
    font-weight: 700;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

.nav-link:hover::after {
    width: 100%;
}

.hamburger {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--text-color);
    margin: 3px 0;
    transition: var(--transition);
}

/* Hero Section */
.hero {
    padding: 8rem 0 4rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.1;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 0.75rem 2rem;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
    font-size: 1rem;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: #2563eb;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: var(--primary-color);
    transform: translateY(-2px);
}

/* Floating animation */
.hero-animation {
    position: relative;
    height: 400px;
}

.floating-card {
    position: absolute;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius);
    padding: 2rem;
    font-size: 1.5rem;
    font-weight: 600;
    color: white;
    animation: float 6s ease-in-out infinite;
}

#card1 {
    top: 50px;
    right: 100px;
    animation-delay: 0s;
}

#card2 {
    top: 150px;
    right: 50px;
    animation-delay: 2s;
}

#card3 {
    top: 250px;
    right: 150px;
    animation-delay: 4s;
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    25% { transform: translateY(-20px) rotate(1deg); }
    50% { transform: translateY(-10px) rotate(-1deg); }
    75% { transform: translateY(-15px) rotate(2deg); }
}

/* Sections */
.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--bg-color);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.feature-card p {
    color: var(--text-light);
    line-height: 1.6;
}

/* Demo Section */
.demo {
    padding: 6rem 0;
}

.demo-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: start;
}

.demo-controls {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.demo-btn {
    padding: 0.5rem 1rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.demo-btn:hover {
    background: #2563eb;
    transform: translateY(-2px);
}

.task-manager {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
}

.input-group {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.input-group input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--bg-color);
    color: var(--text-color);
    transition: var(--transition);
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.input-group button {
    padding: 0.75rem 1.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.task-list {
    list-style: none;
    margin-bottom: 1.5rem;
}

.task-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem;
    margin-bottom: 0.5rem;
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    transition: var(--transition);
    animation: slideIn 0.3s ease-out;
}

.task-item:hover {
    transform: translateX(5px);
}

.task-item.completed {
    opacity: 0.6;
    text-decoration: line-through;
}

.task-text {
    flex: 1;
    color: var(--text-color);
}

.task-actions {
    display: flex;
    gap: 0.5rem;
}

.task-btn {
    padding: 0.25rem 0.5rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: var(--transition);
}

.complete-btn {
    background: #10b981;
    color: white;
}

.delete-btn {
    background: #ef4444;
    color: white;
}

.task-stats {
    text-align: center;
    color: var(--text-light);
    font-size: 0.9rem;
}

.code-display {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 2rem;
    position: sticky;
    top: 2rem;
}

.code-display h4 {
    margin-bottom: 1rem;
    color: var(--text-color);
}

.code-display pre {
    background: #1f2937;
    color: #f9fafb;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
}

/* Contact Section */
.contact {
    padding: 6rem 0;
    background: var(--bg-secondary);
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--bg-color);
    color: var(--text-color);
    transition: var(--transition);
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

/* Footer */
.footer {
    background: var(--text-color);
    color: var(--bg-color);
    text-align: center;
    padding: 2rem 0;
}

/* Animations */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .hamburger {
        display: flex;
    }
    
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .demo-container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-animation {
        height: 200px;
    }
    
    .floating-card {
        font-size: 1rem;
        padding: 1rem;
    }
    
    .demo-controls {
        justify-content: center;
    }
    
    .input-group {
        flex-direction: column;
    }
    
    .container {
        padding: 0 1rem;
    }
}