/* Global Variables & Reset */
:root {
    --primary-color: #4f46e5; /* Indigo 600 */
    --primary-hover: #4338ca; /* Indigo 700 */
    --secondary-color: #0f172a; /* Slate 900 */
    --accent-color: #818cf8; /* Indigo 400 */
    --background-color: #f8fafc; /* Slate 50 */
    --surface-color: #ffffff;
    --text-main: #1e293b; /* Slate 800 */
    --text-muted: #64748b; /* Slate 500 */
    --border-color: #e2e8f0; /* Slate 200 */
    --success-color: #10b981;
    --error-color: #ef4444;
    --radius-lg: 16px;
    --radius-md: 8px;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-main);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    text-decoration: none;
    color: inherit;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    color: var(--secondary-color);
    font-weight: 700;
    line-height: 1.2;
}

h1 { font-size: 2.5rem; margin-bottom: 1rem; }
h2 { font-size: 2rem; margin-bottom: 0.75rem; }
p { color: var(--text-muted); margin-bottom: 1.5rem; }

/* Layout Utilities */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

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

.min-h-screen {
    min-height: 100vh;
}

/* Components */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-weight: 600;
    border-radius: var(--radius-md);
    transition: all 0.2s ease;
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 4px 6px -1px rgba(79, 70, 229, 0.2);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 6px 8px -1px rgba(79, 70, 229, 0.3);
}

.btn-primary:disabled {
    background-color: var(--text-muted);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.card {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: 2.5rem;
    border: 1px solid var(--border-color);
}

/* Form Elements */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--secondary-color);
}

.form-input, .form-select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
    background-color: #fff;
}

.form-input:focus, .form-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* Header */
.header {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 50;
    padding: 1rem 0;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Hero Section */
.hero {
    padding: 6rem 0;
    text-align: center;
    background: radial-gradient(circle at top center, #e0e7ff 0%, transparent 70%);
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.025em;
    margin-bottom: 1.5rem;
    background: linear-gradient(to right, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto 2.5rem;
}

/* Utility Classes */
.text-center { text-align: center; }
.mt-4 { margin-top: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.text-sm { font-size: 0.875rem; }
.text-error { color: var(--error-color); }
.hidden { display: none; }

/* Animations */
@keyframes spin {
    to { transform: rotate(360deg); }
}

.spinner {
    display: inline-block;
    width: 1.25rem;
    height: 1.25rem;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s linear infinite;
    margin-right: 0.5rem;
}

/* Responsive */
@media (max-width: 640px) {
    .hero-title { font-size: 2.5rem; }
    .card { padding: 1.5rem; }
}