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

:root {
    --primary-color: #4F46E5;
    --primary-dark: #4338CA;
    --secondary-color: #64748B;
    --background: #F8FAFC;
    --surface: #FFFFFF;
    --text-primary: #1E293B;
    --text-secondary: #64748B;
    --border: #E2E8F0;
    --error: #EF4444;
    --success: #10B981;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
.navbar {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.nav-brand h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.nav-brand a {
    text-decoration: none;
}

.nav-links, .nav-user {
    display: flex;
    gap: 1rem;
    align-items: center;
}

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

/* Buttons */
.btn-primary, .btn-secondary, .btn-large {
    padding: 0.5rem 1.5rem;
    border: none;
    border-radius: 0.5rem;
    font-size: 1rem;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: all 0.2s;
}

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

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

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

.btn-secondary:hover {
    background: var(--background);
}

.btn-large {
    padding: 0.75rem 2rem;
    font-size: 1.125rem;
    font-weight: 600;
}

.btn-block {
    width: 100%;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    text-align: center;
}

.hero h2 {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.hero-actions {
    margin-top: 2rem;
}

/* Features Section */
.features {
    padding: 4rem 0;
}

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

.feature-card {
    background: var(--surface);
    padding: 2rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border);
    text-align: center;
}

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

.feature-card p {
    color: var(--text-secondary);
}

/* Footer */
footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 2rem 0;
    margin-top: 4rem;
    text-align: center;
    color: var(--text-secondary);
}

/* Auth Page */
.auth-page {
    min-height: calc(100vh - 200px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem 0;
}

.auth-container {
    width: 100%;
    max-width: 450px;
    padding: 0 20px;
}

.auth-box {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    padding: 2rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.auth-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border);
}

.tab-btn {
    flex: 1;
    padding: 0.75rem;
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all 0.2s;
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.auth-form h2 {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.error-message, .success-message {
    padding: 0.75rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
}

.error-message {
    background: #FEE2E2;
    color: var(--error);
    border: 1px solid #FECACA;
}

.success-message {
    background: #D1FAE5;
    color: var(--success);
    border: 1px solid #A7F3D0;
}

/* Responsive */
@media (max-width: 768px) {
    .hero h2 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

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