:root {
    /* Default Dark Theme (Matches Main Site) */
    --color-bg-main: #0f172a;
    /* Slate-950 */
    --color-bg-card: rgba(30, 41, 59, 0.7);
    /* Slate-800 alpha */
    --color-text-main: #f1f5f9;
    /* Slate-100 */
    --color-text-muted: #cbd5e1;
    /* Slate-300 */
    --color-primary: #38bdf8;
    /* Sky-400 */
    --color-accent: #818cf8;
    /* Indigo-400 */
    --color-border: rgba(148, 163, 184, 0.15);
    --color-input-bg: rgba(15, 23, 42, 0.6);
    --color-button-text: #0f172a;

    /* Graph/Visualizer Specifics */
    --color-graph-bg: #1e293b;
    /* Slate-800 */
    --color-node-bg: #38bdf8;
    --color-node-text: #0f172a;
    --color-edge: #94a3b8;
}

[data-theme="light"] {
    --color-bg-main: #f8fafc;
    /* Slate-50 */
    --color-bg-card: #ffffff;
    --color-text-main: #0f172a;
    /* Slate-900 */
    --color-text-muted: #475569;
    /* Slate-600 */
    --color-primary: #0284c7;
    /* Sky-600 */
    --color-accent: #6366f1;
    /* Indigo-500 */
    --color-border: #e2e8f0;
    --color-input-bg: #ffffff;
    --color-button-text: #ffffff;

    /* Graph/Visualizer Specifics */
    --color-graph-bg: #ffffff;
    --color-node-bg: #0ea5e9;
    --color-node-text: #ffffff;
    --color-edge: #64748b;
}

body {
    background-color: var(--color-bg-main) !important;
    color: var(--color-text-main) !important;
    transition: background-color 0.3s, color 0.3s;
}

h1,
h2,
h3,
label,
span {
    color: var(--color-text-main) !important;
}

/* Common Controls Styling */
input,
select {
    background-color: var(--color-input-bg) !important;
    border: 1px solid var(--color-border) !important;
    color: var(--color-text-main) !important;
    padding: 5px 10px;
    border-radius: 6px;
}

button {
    background-color: var(--color-primary) !important;
    color: var(--color-button-text) !important;
    border: none !important;
    border-radius: 6px;
    padding: 6px 12px;
    cursor: pointer;
    font-weight: 600;
    transition: transform 0.1s, background-color 0.2s;
}

button:hover {
    background-color: var(--color-accent) !important;
    color: white !important;
}

button.active,
button.selected {
    background-color: var(--color-accent) !important;
    color: white !important;
}

button:disabled {
    background-color: var(--color-border) !important;
    color: var(--color-text-muted) !important;
    cursor: not-allowed;
    opacity: 0.6;
}

/* SVG Containers usually have white background in original files */
svg {
    background-color: var(--color-graph-bg) !important;
    border-color: var(--color-border) !important;
}

/* Theme Toggle Button Fixed Position */
#theme-toggle-btn {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--color-bg-card) !important;
    border: 1px solid var(--color-border) !important;
    color: var(--color-text-main) !important;
    font-size: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 9999;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

#theme-toggle-btn:hover {
    transform: scale(1.1);
    border-color: var(--color-primary) !important;
}

/* Back to Home Link */
.back-link {
    position: fixed;
    top: 20px;
    left: 20px;
    color: var(--color-text-muted) !important;
    text-decoration: none;
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 5px;
    z-index: 9999;
}

.back-link:hover {
    color: var(--color-primary) !important;
}

/* =========================================
   Universal Overrides for Visualizer SVGs
   ========================================= */

/* Default Node Styling */
.node-circle {
    fill: var(--color-node-bg) !important;
    stroke: var(--color-primary) !important;
    stroke-width: 2px;
}

/* Node Text */
.node-text {
    fill: var(--color-node-text) !important;
    font-weight: bold;
}

/* Default Edge Styling */
.edge-line,
.edge {
    stroke: var(--color-edge) !important;
}

/* Edge Weights/Labels */
.edge-weight,
.edge-flow,
.node-text-small {
    fill: var(--color-text-muted) !important;
}

/* Specific State Overrides (Ensure visibility on dark bg) */
/* We keep original colors but might need slight adjustments if they clash */

/* Visited / Source (Green) */
.node-visited,
.node-source,
.node-final {
    fill: #22c55e !important;
    /* Tailwind green-500 */
    stroke: #14532d !important;
    /* Tailwind green-900 */
}

/* Current / Processing (Amber/Yellow) */
.node-current,
.node-highlight {
    fill: #eab308 !important;
    /* Tailwind yellow-500 */
    stroke: #422006 !important;
    /* yellow-950 */
    color: #422006 !important;
}

/* Selected / Target (Orange/Red) */
.node-selected-1,
.node-selected-2,
.node-sink {
    fill: #f97316 !important;
    /* Tailwind orange-500 */
    stroke: #431407 !important;
}

/* MST / Path Edges (Pink/Magenta) */
.edge-mst,
.edge-path,
.edge-augment {
    stroke: #ec4899 !important;
    /* Tailwind pink-500 */
    stroke-width: 4px !important;
}

/* Current Edge (Yellow) */
.edge-current {
    stroke: #eab308 !important;
}