/* CSS Custom Properties */
:root {
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    --secondary: #64748b;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --purple: #8b5cf6;

    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;

    --border-color: #e2e8f0;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.06);

    --sidebar-width: 260px;
    --header-height: 70px;
    --radius: 12px;
    --radius-sm: 8px;
}

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

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

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

/* Login Page */
.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

.login-container {
    width: 100%;
    max-width: 420px;
    padding: 1rem;
}

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

.login-header {
    text-align: center;
    margin-bottom: 2rem;
}

.login-icon {
    width: 48px;
    height: 48px;
    color: var(--primary);
    margin-bottom: 1rem;
}

.login-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.login-header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Alert */
.alert {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.875rem 1rem;
    border-radius: var(--radius-sm);
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.alert svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.alert-error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #dc2626;
}

.alert-error svg {
    color: var(--danger);
}

/* Form */
.login-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.input-wrapper {
    position: relative;
}

.input-wrapper svg {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    color: var(--text-muted);
}

.input-wrapper input {
    width: 100%;
    padding: 0.875rem 1rem 0.875rem 2.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: all 0.2s;
}

.input-wrapper input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.btn svg {
    width: 18px;
    height: 18px;
}

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

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

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

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

/* App Layout */
.app-container {
    display: flex;
    min-height: 100vh;
    width: 100%;
    overflow-x: hidden;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    left: 0;
    top: 0;
}

.sidebar-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.logo-icon {
    width: 32px;
    height: 32px;
    color: var(--primary);
}

.logo-text {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.sidebar-nav {
    flex: 1;
    padding: 1rem 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.2s;
}

.nav-item svg {
    width: 20px;
    height: 20px;
}

.nav-item:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.nav-item.active {
    background: rgba(59, 130, 246, 0.1);
    color: var(--primary);
}

.sidebar-footer {
    padding: 1rem 1.25rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.user-avatar {
    width: 36px;
    height: 36px;
    background: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.9rem;
}

.user-name {
    font-size: 0.9rem;
    font-weight: 500;
}

.logout-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    color: var(--text-muted);
    transition: all 0.2s;
}

.logout-btn:hover {
    background: var(--bg-tertiary);
    color: var(--danger);
}

.logout-btn svg {
    width: 20px;
    height: 20px;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 1.5rem 2rem;
    min-width: 0;
    overflow-x: hidden;
}

.content-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 2rem;
}

.header-title h1 {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.header-title p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.time-range-select {
    padding: 0.625rem 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.9rem;
    cursor: pointer;
}

.time-range-select:focus {
    outline: none;
    border-color: var(--primary);
}

.date-picker {
    padding: 0.625rem 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.9rem;
    cursor: pointer;
}

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

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1.25rem;
    margin-bottom: 2rem;
    width: 100%;
}

.stat-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}

.stat-icon svg {
    width: 24px;
    height: 24px;
}

.stat-icon.blue {
    background: rgba(59, 130, 246, 0.15);
    color: var(--primary);
}

.stat-icon.green {
    background: rgba(16, 185, 129, 0.15);
    color: var(--success);
}

.stat-icon.orange {
    background: rgba(245, 158, 11, 0.15);
    color: var(--warning);
}

.stat-icon.purple {
    background: rgba(139, 92, 246, 0.15);
    color: var(--purple);
}

.stat-icon.teal {
    background: rgba(20, 184, 166, 0.15);
    color: #14b8a6;
}

.stat-content {
    display: flex;
    flex-direction: column;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 600;
}

/* Chart Container */
.chart-container {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
}

.chart-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.5rem;
}

.chart-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
}

.chart-actions {
    display: flex;
    gap: 0.5rem;
}

.chart-type-btn {
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.2s;
}

.chart-type-btn:hover {
    background: var(--bg-tertiary);
}

.chart-type-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

.chart-wrapper {
    position: relative;
    height: 400px;
}

/* Chart Loading & Error States */
.chart-loading,
.chart-error {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    z-index: 10;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.chart-loading p,
.chart-error p {
    margin-top: 1rem;
    color: var(--text-secondary);
}

.chart-error svg {
    width: 48px;
    height: 48px;
    color: var(--warning);
}

.chart-error .btn {
    margin-top: 1rem;
}

/* Responsive */
@media (max-width: 1024px) {
    .sidebar {
        width: 70px;
    }

    .sidebar-header .logo-text,
    .nav-item span,
    .user-name {
        display: none;
    }

    .sidebar-header {
        justify-content: center;
    }

    .nav-item {
        justify-content: center;
        padding: 0.75rem;
    }

    .sidebar-footer {
        flex-direction: column;
        gap: 0.5rem;
    }

    .main-content {
        margin-left: 70px;
    }
}

@media (max-width: 768px) {
    .content-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .header-actions {
        width: 100%;
        flex-wrap: wrap;
    }

    .header-actions .btn,
    .time-range-select,
    .date-picker {
        flex: 1 1 auto;
    }
}

@media (max-width: 600px) {
    .main-content {
        padding: 1rem;
    }
}