:root {
    /* Color System - Dark Theme based on Slate/Zinc */
    --bg-body: #0f172a;
    --bg-surface: #1e293b;
    --bg-surface-hover: #334155;
    --bg-input: #0f172a;
    
    /* Primary Brand Colors */
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --primary-glow: rgba(59, 130, 246, 0.5);
    
    /* Functional Colors */
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #0ea5e9;
    
    /* Text Colors */
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    --text-inverse: #0f172a;
    
    /* Borders & Separators */
    --border: #334155;
    --border-light: #475569;
    
    /* Effects */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 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);
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
}

/* Global Reset & Base */
body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* Navbar Styling */
.navbar {
    background-color: var(--bg-surface) !important;
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(8px);
}

.navbar-brand {
    color: var(--text-main) !important;
    font-weight: 700;
    letter-spacing: -0.5px;
    font-size: 1.25rem;
}

/* Card System */
.card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s, box-shadow 0.2s;
    overflow: hidden;
    margin-bottom: 1.5rem;
}

.card:hover {
    border-color: var(--border-light);
    box-shadow: var(--shadow-md);
}

.card-header {
    background-color: rgba(255, 255, 255, 0.02);
    border-bottom: 1px solid var(--border);
    padding: 1rem 1.5rem;
    font-weight: 600;
    color: var(--text-main);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.card-header h5 {
    margin: 0;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.card-body {
    padding: 1.5rem;
    color: var(--text-muted);
}

/* Tabs Styling */
.nav-tabs {
    border-bottom: 1px solid var(--border);
    margin-bottom: 2rem;
    gap: 0.5rem;
}

.nav-tabs .nav-link {
    color: var(--text-muted);
    border: none;
    background: transparent;
    padding: 0.75rem 1.25rem;
    border-radius: var(--radius-md);
    font-weight: 500;
    transition: all 0.2s;
}

.nav-tabs .nav-link:hover {
    color: var(--text-main);
    background-color: rgba(255, 255, 255, 0.05);
}

.nav-tabs .nav-link.active {
    color: var(--primary);
    background-color: rgba(59, 130, 246, 0.1);
    font-weight: 600;
}

/* Form Elements */
.form-label {
    color: var(--text-main);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.form-control, .form-select {
    background-color: var(--bg-input);
    border: 1px solid var(--border);
    color: var(--text-main);
    border-radius: var(--radius-md);
    padding: 0.625rem 1rem;
    transition: all 0.2s;
}

.form-control:focus, .form-select:focus {
    background-color: var(--bg-input);
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
    color: var(--text-main);
}

.form-control::placeholder {
    color: #64748b;
}

/* Buttons */
.btn {
    padding: 0.625rem 1.25rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary {
    background-color: var(--primary);
    border: none;
    box-shadow: 0 4px 6px -1px rgba(59, 130, 246, 0.2);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    box-shadow: 0 10px 15px -3px rgba(59, 130, 246, 0.3);
    transform: translateY(-1px);
}

.btn-success {
    background-color: var(--success);
    border: none;
    color: #fff;
}

.btn-success:hover {
    background-color: #059669;
    transform: translateY(-1px);
}

.btn-outline-primary {
    border-color: var(--border);
    color: var(--text-muted);
    background: transparent;
}

.btn-outline-primary:hover, 
.btn-outline-primary.active {
    background-color: var(--bg-surface-hover);
    border-color: var(--primary);
    color: var(--primary);
}

/* Data Displays & Logs */
#log {
    background-color: #000000;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
}

#log p {
    color: #cbd5e1;
    border-left: 2px solid var(--border);
    padding-left: 0.75rem;
    margin-bottom: 0.5rem;
}

.target-item {
    background-color: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.2);
    color: #fbbf24;
    border-radius: var(--radius-md);
    padding: 0.75rem;
    margin-bottom: 0.75rem;
    transition: all 0.2s;
}

.target-item:hover {
    background-color: rgba(245, 158, 11, 0.15);
    transform: translateX(4px);
    border-color: #fbbf24;
}

/* Metrics Dashboard */
#metrics p {
    background-color: rgba(255, 255, 255, 0.03);
    padding: 0.75rem 1rem;
    border-radius: var(--radius-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid transparent;
}

#metrics p:hover {
    border-color: var(--border);
}

#metrics strong {
    color: var(--text-muted);
    font-weight: 500;
}

#metrics span {
    color: var(--primary);
    font-weight: 700;
    font-family: 'JetBrains Mono', monospace;
}

/* Visualization Area */
#plotDiv {
    background-color: var(--bg-body);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 0.5rem;
}

/* Modal Styling */
.modal-content {
    background-color: var(--bg-surface);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
}

.modal-header {
    border-bottom-color: var(--border);
}

.modal-footer {
    border-top-color: var(--border);
}

.btn-close-white {
    filter: invert(1) grayscale(100%) brightness(200%);
}

/* Utils */
.text-muted {
    color: #64748b !important;
}

hr {
    border-color: var(--border);
    opacity: 0.5;
}

/* Tooltips */
.tooltip-inner {
    background-color: var(--bg-surface-hover);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
}

.tooltip-arrow::before {
    border-top-color: var(--border) !important;
}

/* Plotly Dark Mode Overrides */
.js-plotly-plot .plotly .main-svg {
    background: transparent !important;
}

.js-plotly-plot .plotly .bg {
    fill: transparent !important;
}

.js-plotly-plot .plotly .gridlayer path {
    stroke: var(--border) !important;
    stroke-opacity: 0.3;
}

.js-plotly-plot .plotly text {
    fill: var(--text-muted) !important;
}