/* CSS Variables - Dark Theme */
:root {
    /* Colors */
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #10b981;
    --secondary-hover: #059669;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --warning-color: #f59e0b;

    /* Dark Theme Colors */
    --bg-primary: #1f2937;
    --bg-secondary: #111827;
    --bg-tertiary: #374151;
    --bg-hover: #4b5563;

    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --text-muted: #9ca3af;

    --border-color: #374151;
    --border-hover: #4b5563;

    /* 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: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.3);

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Z-index */
    --z-dropdown: 100;
    --z-modal: 200;
    --z-toast: 300;
    --z-overlay: 400;
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }

p {
    margin-bottom: var(--spacing-md);
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-muted {
    color: var(--text-muted);
}

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    text-align: center;
    padding: var(--spacing-2xl) 0;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
}

.tagline {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    width: 100%;
    max-width: 800px;
}

/* Card */
.card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.card-header {
    margin-bottom: var(--spacing-lg);
}

.card-header h2 {
    margin-bottom: var(--spacing-sm);
}

.card-header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0;
}

.card-body {
    /* Card body styles */
}

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

label {
    display: block;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

input[type="text"],
input[type="password"],
textarea {
    width: 100%;
    padding: var(--spacing-md);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color var(--transition-fast);
}

input[type="text"]:focus,
input[type="password"]:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

input[type="text"]::placeholder,
input[type="password"]::placeholder,
textarea::placeholder {
    color: var(--text-muted);
}

.error-message {
    display: block;
    color: var(--danger-color);
    font-size: 0.85rem;
    margin-top: var(--spacing-xs);
    min-height: 1.2rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-hover);
}

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

.btn-secondary:hover:not(:disabled) {
    background-color: var(--secondary-hover);
}

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

.btn-danger:hover:not(:disabled) {
    background-color: var(--danger-hover);
}

.btn-block {
    width: 100%;
}

.btn-icon {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1.2rem;
    cursor: pointer;
    padding: var(--spacing-sm);
    transition: color var(--transition-fast);
}

.btn-icon:hover {
    color: var(--text-primary);
}

/* Footer */
.footer {
    text-align: center;
    padding: var(--spacing-xl) 0;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Loading Spinner */
.spinner {
    width: 50px;
    height: 50px;
    position: relative;
    animation: spin 1.2s cubic-bezier(0.5, 0, 0.5, 1) infinite;
}

.spinner::before,
.spinner::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    border: 4px solid transparent;
}

.spinner::before {
    border-top-color: var(--primary-color);
    animation: spin 1.2s cubic-bezier(0.5, 0, 0.5, 1) infinite;
}

.spinner::after {
    border-bottom-color: var(--secondary-color);
    animation: spin 1.5s cubic-bezier(0.5, 0, 0.5, 1) infinite reverse;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Pulse animation for waiting states */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.7;
        transform: scale(0.95);
    }
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--bg-hover);
}