:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --secondary-color: #64748b;
    --background-color: #f8fafc;
    --surface-color: #ffffff;
    --text-color: #0f172a;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --error-color: #ef4444;
    --radius: 0.5rem;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

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

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s;
}

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header & Nav */
header {
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    letter-spacing: -0.025em;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

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

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
}

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

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

.btn-outline {
    border: 1px solid var(--border-color);
    background: transparent;
}

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    padding: 6rem 0;
    text-align: center;
    background: linear-gradient(to bottom, var(--surface-color), var(--background-color));
}

.hero h1 {
    font-size: 3.5rem;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    background: -webkit-linear-gradient(45deg, var(--text-color), var(--primary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 700px;
    margin: 0 auto 2.5rem;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* Features Section */
.features {
    padding: 5rem 0;
    background: var(--surface-color);
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title h2 {
    font-size: 2.25rem;
    margin-bottom: 1rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--background-color);
    padding: 2rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    transition: transform 0.2s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
}

.card h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

/* Pricing */
.pricing {
    padding: 5rem 0;
}

.price-card {
    background: var(--surface-color);
    padding: 2.5rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    text-align: center;
    position: relative;
    box-shadow: var(--shadow);
}

.price-card.featured {
    border-color: var(--primary-color);
    transform: scale(1.05);
    z-index: 10;
}

.price {
    font-size: 3rem;
    font-weight: 700;
    margin: 1.5rem 0;
    color: var(--text-color);
}

.price span {
    font-size: 1rem;
    color: var(--text-muted);
    font-weight: 400;
}

.features-list {
    margin: 2rem 0;
    text-align: left;
}

.features-list li {
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.check-icon {
    color: var(--success-color);
}

/* Footer */
footer {
    background: var(--text-color);
    color: white;
    padding: 3rem 0;
    text-align: center;
}

footer p {
    color: var(--secondary-color);
}

/* Auth Pages */
.auth-container {
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.auth-box {
    background: var(--surface-color);
    padding: 2.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 400px;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.1);
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .price-card.featured {
        transform: none;
    }
}