/**
 * AntiGravity Web App Styles
 * Vanilla CSS implementation focused on premium scientific tool aesthetics.
 */

/* ==========================================================================
   CSS Variables & Tokens
   ========================================================================== */
:root {
    /* Color Palette - Premium Analytics */
    --clr-bg-app: #f5f7f9;
    --clr-bg-panel: #ffffff;
    --clr-border: #e2e8f0;
    --clr-primary: #3b82f6; /* Modern Blue */
    --clr-primary-hover: #2563eb;
    --clr-text-main: #0f172a;
    --clr-text-muted: #64748b;
    
    /* Semantic Colors */
    --clr-success: #10b981;
    --clr-warning: #f59e0b;
    --clr-danger: #ef4444;

    /* Typography */
    --font-ui: 'Inter', system-ui, -apple-system, sans-serif;
    --font-scientific: 'Lora', Georgia, serif;
    --font-mono: 'Fira Code', 'Courier New', monospace;

    /* Layout & Sizing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;

    --sidebar-width: 320px;
    --header-height: 60px;
    
    /* Shadows */
    --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);

    /* Chart specific vars (overridden via JS or themes) */
    --chart-bg: #ffffff;
    --chart-axis: #475569;
    --chart-grid: #e2e8f0;
    --chart-text: #1e293b;
    --chart-font: var(--font-ui);
}

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

body {
    font-family: var(--font-ui);
    background-color: var(--clr-bg-app);
    color: var(--clr-text-main);
    line-height: 1.5;
    font-size: 14px;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
    font-weight: 600;
    color: var(--clr-text-main);
}

/* ==========================================================================
   Layout Structure
   ========================================================================== */
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
}

.app-header {
    height: var(--header-height);
    background-color: var(--clr-bg-panel);
    border-bottom: 1px solid var(--clr-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-lg);
    flex-shrink: 0;
    z-index: 10;
}

.app-main {
    display: flex;
    flex: 1;
    overflow: hidden; /* prevents scrolling at the main wrapper */
}

/* ==========================================================================
   Header Components
   ========================================================================== */
.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--clr-text-main);
}

.logo .badge {
    font-size: 0.7rem;
    background-color: var(--clr-border);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    color: var(--clr-text-muted);
}

.header-actions {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

/* ==========================================================================
   Buttons & Forms
   ========================================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 8px 16px;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    font-family: var(--font-ui);
}

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

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

.btn-secondary {
    background-color: white;
    color: var(--clr-text-main);
    border: 1px solid var(--clr-border);
}

.btn-secondary:hover {
    background-color: var(--clr-bg-app);
}

.btn-outline {
    background-color: transparent;
    color: var(--clr-text-main);
    border: 1px solid var(--clr-border);
    padding: 6px 12px;
}

.btn-outline:hover {
    border-color: var(--clr-text-main);
}

.btn-text {
    background: none;
    color: var(--clr-primary);
    padding: 6px 12px;
}
.btn-text:hover {
    text-decoration: underline;
}

.icon {
    width: 16px;
    height: 16px;
}

/* ==========================================================================
   Sidebar Controls
   ========================================================================== */
.sidebar-controls {
    width: var(--sidebar-width);
    background-color: var(--clr-bg-panel);
    border-right: 1px solid var(--clr-border);
    display: flex;
    flex-direction: column;
    padding: var(--spacing-lg);
    overflow-y: auto;
    flex-shrink: 0;
}

.control-group {
    margin-bottom: var(--spacing-xl);
}

.group-title {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--clr-text-muted);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-xs);
    border-bottom: 1px solid var(--clr-border);
}

.control-item {
    margin-bottom: var(--spacing-md);
}

.control-item label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
    color: var(--clr-text-main);
}

.select-field {
    width: 100%;
    padding: 8px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--clr-border);
    font-family: var(--font-ui);
    font-size: 0.9rem;
    background-color: var(--clr-bg-panel);
    color: var(--clr-text-main);
    outline: none;
}
.select-field:focus {
    border-color: var(--clr-primary);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}
.select-field:disabled {
    background-color: var(--clr-bg-app);
    color: var(--clr-text-muted);
    cursor: not-allowed;
}

.scale-toggle {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xs);
    font-size: 0.8rem;
}

.scale-toggle label {
    display: flex;
    align-items: center;
    gap: 4px;
    font-weight: normal;
    cursor: pointer;
}

.range-slider {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}
.range-slider input[type=range] {
    flex: 1;
}
.range-val {
    font-size: 0.75rem;
    color: var(--clr-text-muted);
}

.export-actions {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}
#export-data {
    grid-column: 1 / -1;
    text-align: center;
}

/* ==========================================================================
   Toggles (Switch)
   ========================================================================== */
.toggle-switch {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}
.toggle-switch span {
    font-size: 0.9rem;
}

.switch {
    position: relative;
    display: inline-block;
    width: 36px;
    height: 20px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #cbd5e1;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 2px;
    bottom: 2px;
    background-color: white;
    transition: .4s;
}

input:checked + .slider {
    background-color: var(--clr-primary);
}

input:focus + .slider {
    box-shadow: 0 0 1px var(--clr-primary);
}

input:checked + .slider:before {
    transform: translateX(16px);
}

.slider.round {
    border-radius: 20px;
}
.slider.round:before {
    border-radius: 50%;
}

/* ==========================================================================
   Chart Area
   ========================================================================== */
.chart-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: var(--spacing-lg) var(--spacing-xl);
    position: relative;
    background-color: var(--clr-bg-app);
}

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

.chart-title {
    font-size: 1.5rem;
    font-weight: 600;
}

.chart-subtitle {
    color: var(--clr-text-muted);
    font-size: 0.95rem;
    margin-top: var(--spacing-xs);
}

.d3-wrapper {
    flex: 1;
    background-color: var(--chart-bg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--clr-border);
    position: relative;
    min-height: 400px; /* Minimum height for small screens */
    overflow: hidden;
}

.empty-state {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    color: var(--clr-text-muted);
}
.empty-icon {
    width: 48px;
    height: 48px;
    margin-bottom: var(--spacing-sm);
    color: #cbd5e1;
}

/* ==========================================================================
   D3.js SVG Specifics
   ========================================================================== */
/* We will inject SVG styles dynamically for export, but here are the defaults */
.axis-line {
    stroke: var(--chart-axis);
    stroke-width: 1.5px;
}
.tick line {
    stroke: var(--chart-grid);
    /* For tick marks on axis */
}
.grid-line line {
    stroke: var(--chart-grid);
    stroke-dasharray: 2, 2;
}
.axis-label {
    fill: var(--chart-text);
    font-family: var(--chart-font);
    font-size: 14px;
    font-weight: 500;
}
.tick-text {
    fill: var(--chart-text);
    font-family: var(--chart-font);
    font-size: 12px;
}
.data-point {
    stroke-width: 1px;
    opacity: 0.8;
    transition: r 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275), stroke-width 0.2s, opacity 0.2s;
    cursor: pointer;
}
.data-point:hover {
    stroke-width: 2px;
    stroke: #0f172a;
    opacity: 1;
}

.point-label {
    fill: var(--chart-text);
    font-family: var(--chart-font);
    font-size: 11px;
    pointer-events: none;
    text-shadow: 0 1px 0 #fff, 1px 0 0 #fff, 0 -1px 0 #fff, -1px 0 0 #fff; /* Halo effect for text readability */
}

/* D3 Tooltip */
.chart-tooltip {
    position: absolute;
    background-color: rgba(255, 255, 255, 0.95);
    border: 1px solid var(--clr-border);
    border-radius: var(--radius-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    box-shadow: var(--shadow-md);
    pointer-events: none;
    font-family: var(--font-ui);
    font-size: 0.85rem;
    z-index: 100;
    transition: opacity 0.2s;
    backdrop-filter: blur(4px);
    color: var(--clr-text-main);
}
.tooltip-title {
    font-weight: 600;
    margin-bottom: 4px;
    border-bottom: 1px solid var(--clr-border);
    padding-bottom: 4px;
}
.tooltip-row {
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-md);
    margin-bottom: 2px;
}
.tooltip-label {
    color: var(--clr-text-muted);
}
.tooltip-val {
    font-weight: 500;
}

/* ==========================================================================
   Themes (Dynamic via CSS classes on body)
   ========================================================================== */
/* Theme: Nature / Science (Clean Academic) */
body.theme-nature {
    --chart-font: var(--font-scientific);
    --chart-bg: #ffffff;
    --chart-axis: #000000;
    --chart-grid: transparent; /* No grid by default */
    --chart-text: #000000;
}
body.theme-nature .axis-line, body.theme-nature .tick line {
    stroke-width: 1px;
    stroke: #000;
}

/* Theme: IEEE (B&W / High Contrast) */
body.theme-ieee {
    --chart-font: var(--font-scientific);
    --chart-bg: #ffffff;
    --chart-axis: #000000;
    --chart-text: #000000;
}
/* Dots will be overridden to grayscale in JS */

/* Theme: Dark Analytics */
body.theme-dark {
    --clr-bg-app: #0f172a;
    --clr-bg-panel: #1e293b;
    --clr-border: #334155;
    --clr-text-main: #f8fafc;
    --clr-text-muted: #94a3b8;
    
    --chart-bg: #0f172a;
    --chart-axis: #f8fafc;
    --chart-grid: #334155;
    --chart-text: #f8fafc;
}
body.theme-dark .empty-state {
    color: #64748b;
}
body.theme-dark .chart-tooltip {
    background-color: rgba(30, 41, 59, 0.95);
    border-color: #334155;
    color: #f8fafc;
}
body.theme-dark .point-label {
    text-shadow: 0 1px 0 #0f172a, 1px 0 0 #0f172a, 0 -1px 0 #0f172a, -1px 0 0 #0f172a;
}
body.theme-dark .btn-secondary, body.theme-dark .btn-outline {
    background-color: #1e293b;
    color: #f8fafc;
    border-color: #475569;
}
body.theme-dark .select-field {
    background-color: #0f172a;
    color: #f8fafc;
    border-color: #475569;
}

/* Toast System */
.toast-container {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}
.toast {
    background-color: #ffffff;
    color: var(--clr-text-main);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    border-left: 4px solid var(--clr-primary);
    font-size: 0.9rem;
    animation: slideIn 0.3s forwards, fadeOut 0.3s forwards 3s;
    font-family: var(--font-ui);
}
.toast.success { border-left-color: var(--clr-success); }
.toast.error { border-left-color: var(--clr-danger); }

@keyframes slideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}
@keyframes fadeOut {
    from { opacity: 1; }
    to { opacity: 0; visibility: hidden; }
}