/* ===== Modern Premium Design System ===== */

:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --primary: #667eea;
    --primary-dark: #5568d3;
    --secondary: #10b981;
    --secondary-dark: #059669;
    --danger: #ef4444;
    --danger-dark: #dc2626;
    --bg: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --text: #111827;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-secondary);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    padding: 20px;
}

/* ===== Container ===== */
.container {
    max-width: 900px;
    margin: 0 auto;
}

/* ===== Header ===== */
.header {
    text-align: center;
    margin-bottom: 32px;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* ===== Auth Section ===== */
.auth-section {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow-xl);
}

/* ===== Tabs ===== */
.tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 24px;
    background: var(--bg-tertiary);
    padding: 4px;
    border-radius: var(--radius-sm);
}

.tab-btn {
    flex: 1;
    padding: 12px;
    border: none;
    background: transparent;
    cursor: pointer;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
}

.tab-btn.active {
    background: var(--bg);
    color: var(--primary);
    box-shadow: var(--shadow-sm);
}

.tab-btn:hover:not(.active) {
    color: var(--text);
}

/* ===== Forms ===== */
.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    font-size: 14px;
    color: var(--text);
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 15px;
    transition: var(--transition);
    background: var(--bg);
    color: var(--text);
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* ===== Buttons ===== */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-primary {
    background: var(--primary-gradient);
    color: white;
    width: 100%;
    box-shadow: var(--shadow);
}

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

.btn-primary:active {
    transform: translateY(0);
}

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

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

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text);
}

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

.btn-danger {
    background: var(--danger);
    color: white;
    padding: 8px 16px;
    font-size: 14px;
}

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

/* ===== Dashboard ===== */
.dashboard-section {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow-xl);
}

.user-info h2 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 24px;
}

.user-info h2 span {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===== Balance Cards ===== */
.balance-card {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.balance-item {
    background: var(--primary-gradient);
    padding: 24px;
    border-radius: var(--radius-sm);
    color: white;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

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

.balance-item .label {
    font-size: 13px;
    font-weight: 500;
    opacity: 0.9;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.balance-item .value {
    font-size: 32px;
    font-weight: 700;
    margin-top: 8px;
}

/* ===== Tabs Section ===== */
.tabs-section {
    margin-bottom: 24px;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

.action-bar {
    margin-bottom: 20px;
}

/* ===== Usage Stats ===== */
.usage-stats {
    display: grid;
    gap: 12px;
}

.usage-item {
    background: var(--bg-secondary);
    padding: 16px 20px;
    border-radius: var(--radius-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.usage-item:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow);
}

.usage-label {
    font-weight: 500;
    color: var(--text);
}

.usage-value {
    font-weight: 600;
    color: var(--primary);
    font-size: 18px;
}

/* ===== Modal ===== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    animation: fadeIn 0.2s ease;
}

.modal-content {
    background: var(--bg);
    padding: 32px;
    border-radius: var(--radius);
    width: 90%;
    max-width: 480px;
    box-shadow: var(--shadow-xl);
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.modal-content h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text);
}

.modal-actions {
    display: flex;
    gap: 12px;
    margin-top: 24px;
}

.modal-actions button {
    flex: 1;
}

/* ===== Toast ===== */
.toast {
    position: fixed;
    top: 24px;
    right: 24px;
    background: var(--text);
    color: white;
    padding: 14px 24px;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-xl);
    opacity: 0;
    transform: translateX(120%);
    transition: var(--transition);
    z-index: 10000;
    font-weight: 500;
}

.toast.show {
    opacity: 1;
    transform: translateX(0);
}

.toast.success {
    background: var(--secondary);
}

.toast.error {
    background: var(--danger);
}

/* ===== Dashboard Actions ===== */
.dashboard-actions {
    display: flex;
    gap: 12px;
    margin-top: 24px;
}

.dashboard-actions a,
.dashboard-actions button {
    flex: 1;
    text-decoration: none;
    text-align: center;
}

/* ===== Empty State ===== */
.empty-state {
    text-align: center;
    padding: 48px 24px;
    color: var(--text-secondary);
}

.empty-state-icon {
    font-size: 48px;
    margin-bottom: 16px;
    opacity: 0.5;
}

.empty-state-text {
    font-size: 16px;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    body {
        padding: 12px;
    }
    
    .header h1 {
        font-size: 1.75rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .auth-section,
    .dashboard-section {
        padding: 20px;
    }
    
    .balance-card {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        padding: 24px;
    }
    
    .dashboard-actions {
        flex-direction: column;
    }
    
    .toast {
        left: 12px;
        right: 12px;
        top: 12px;
    }
}