:root {
    /* Colors */
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    --secondary: #8b5cf6;
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;

    /* Neutrals */
    --bg: #ffffff;
    --bg-secondary: #f9fafb;
    --text: #1f2937;
    --text-secondary: #6b7280;
    --border: #e5e7eb;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);
}

[data-theme="dark"] {
    --bg: #111827;
    --bg-secondary: #1f2937;
    --text: #f9fafb;
    --text-secondary: #9ca3af;
    --border: #374151;
}

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

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

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: 3rem;
}

h2 {
    font-size: 2.25rem;
}

h3 {
    font-size: 1.875rem;
}

h4 {
    font-size: 1.5rem;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Button */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
    gap: 0.5rem;
}

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

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

.btn-secondary {
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
}

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

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

/* Input */
.input {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg);
    color: var(--text);
    transition: border-color 0.2s ease;
}

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

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

/* Form */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--text);
}

.form-error {
    color: var(--error);
    font-size: 0.875rem;
    margin-top: var(--spacing-xs);
}

/* Card */
.card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

/* Navbar */
.navbar {
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.8);
}

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

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
}

.navbar-nav {
    display: flex;
    gap: var(--spacing-lg);
    list-style: none;
    align-items: center;
}

.navbar-link {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}

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

/* Hero */
.hero {
    padding: 6rem 0;
    text-align: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-lg);
    color: white;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-2xl);
    color: rgba(255, 255, 255, 0.9);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

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

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.feature-card {
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 48px;
    height: 48px;
    background: var(--primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
}

/* Auth Page */
.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: var(--spacing-xl);
}

.auth-card {
    width: 100%;
    max-width: 450px;
}

/* Dashboard */
.dashboard {
    display: grid;
    grid-template-columns: 250px 1fr;
    min-height: 100vh;
}

.sidebar {
    background: var(--bg-secondary);
    border-right: 1px solid var(--border);
    padding: var(--spacing-xl);
}

.sidebar-nav {
    list-style: none;
}

.sidebar-link {
    display: block;
    padding: var(--spacing-md);
    color: var(--text);
    text-decoration: none;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    transition: background 0.2s ease;
}

.sidebar-link:hover {
    background: var(--bg);
}

.main-content {
    padding: var(--spacing-2xl);
}

/* Responsive */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

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

    .sidebar {
        display: none;
    }
}