:root {
    --bg-color: #FAFAFA;
    --text-main: #111827;
    --text-muted: #4B5563;
    
    /* Bold flat colors */
    --accent-blue: #2563EB;
    --accent-green: #10B981;
    --accent-red: #EF4444;
    --accent-yellow: #F59E0B;
    
    --border-color: #E5E7EB;
    --surface: #FFFFFF;
    
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 32px;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Inter', system-ui, sans-serif;
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.text-center {
    text-align: center;
}

/* Typography */
h1, h2, h3, h4 {
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
    color: var(--text-main);
}

h1 { font-size: 3rem; letter-spacing: -0.05em; }
h2 { font-size: 2rem; border-bottom: 4px solid var(--accent-yellow); display: inline-block; margin-bottom: var(--spacing-md); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1rem; text-transform: uppercase; letter-spacing: 0.05em; }

p {
    margin-bottom: var(--spacing-md);
    color: var(--text-muted);
}

strong {
    color: var(--text-main);
}

a {
    color: var(--accent-blue);
    text-decoration: underline;
    text-decoration-thickness: 2px;
    text-underline-offset: 4px;
    font-weight: 600;
}
a:hover {
    color: #1D4ED8;
    background-color: #DBEAFE;
}

/* Header */
.header {
    background-color: var(--surface);
    padding: var(--spacing-lg) 0;
    border-bottom: 2px solid var(--text-main);
    margin-bottom: var(--spacing-lg);
}

.header h1 {
    margin-bottom: 0;
}
.header p {
    font-size: 1.2rem;
    margin-bottom: 0;
    color: var(--accent-blue);
    font-weight: 600;
}

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

.github-link {
    color: var(--text-main);
    transition: transform 0.2s, color 0.2s;
    background: none !important;
    text-decoration: none;
}

.github-link:hover {
    color: var(--accent-blue);
    transform: scale(1.1);
}

/* Sections */
section {
    margin-bottom: 4rem;
}

/* Guidance block reset since moved down */
.guidance-box {
    background-color: var(--surface);
    border: 3px solid var(--text-main);
    padding: var(--spacing-md);
    border-radius: 8px;
    box-shadow: 4px 4px 0px var(--text-main);
    height: 100%;
}
.guidance-box h3 {
    color: var(--accent-red);
    border-bottom: 2px solid var(--accent-red);
    padding-bottom: 8px;
    margin-bottom: var(--spacing-md);
    display: inline-block;
}

/* Sections at the bottom */
.guidance-and-math {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.guidance-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.good {
    background-color: #ECFDF5;
    padding: var(--spacing-md);
    border-radius: 4px;
    border: 2px solid var(--accent-green);
}
.good h4 { color: var(--accent-green); }

.bad {
    background-color: #FEF2F2;
    padding: var(--spacing-md);
    border-radius: 4px;
    border: 2px solid var(--accent-red);
}
.bad h4 { color: var(--accent-red); }

ul {
    padding-left: 20px;
    color: var(--text-muted);
}
.bad ul { margin-bottom: var(--spacing-sm); }
.small-text { font-size: 0.85rem; margin-bottom: 0; font-style: italic;}

/* App Interface Layout */
.app-interface {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    background-color: var(--surface);
    padding: var(--spacing-md);
    border: 3px solid var(--text-main);
    border-radius: 8px;
    box-shadow: 6px 6px 0px var(--text-main);
}

/* Canvas Area */
.canvas-container {
    position: relative;
    background-color: #111; /* Dark background strictly for the drawing canvas contrast */
    border-radius: 4px;
    overflow: hidden;
    min-height: 600px; /* Made significantly larger */
    border: 2px solid var(--text-main);
    width: 100%;
}

canvas {
    display: block;
    width: 100%;
    height: 100%;
}

.status-overlay {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--surface);
    color: var(--text-main);
    padding: 8px 16px;
    border: 2px solid var(--text-main);
    font-weight: 600;
    pointer-events: none;
    transition: opacity 0.2s;
    box-shadow: 3px 3px 0px rgba(0,0,0,0.1);
}

.status-overlay.hidden {
    opacity: 0;
}

/* Equation Bar */
.equation-container {
    position: relative;
    width: 100%;
    margin-top: var(--spacing-md);
    display: flex;
    align-items: stretch;
    background: rgba(17, 17, 17, 0.4);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: inset 0px 4px 10px rgba(0, 0, 0, 0.5);
}

.equation-bar {
    flex-grow: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    text-align: left;
    overflow-x: auto;
    overflow-y: hidden;
    white-space: nowrap !important;
    color: var(--text-light);
    font-size: 0.95em;
    min-height: 40px;
}

/* Force KaTeX to never line wrap */
.equation-bar .katex, 
.equation-bar .katex-html {
    white-space: nowrap !important;
}
.equation-bar .base {
    display: inline-block !important;
    white-space: nowrap !important;
}

.equation-bar::-webkit-scrollbar {
    height: 6px;
}

.equation-bar::-webkit-scrollbar-thumb {
    background: var(--accent-blue);
    border-radius: 3px;
}

.copy-btn {
    background: rgba(30, 30, 30, 0.6);
    border: none;
    border-left: 1px solid var(--border-color);
    color: var(--text-light);
    padding: 0 15px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.copy-btn:hover {
    background: var(--accent-blue);
    color: white;
}

.copy-btn.hidden {
    display: none;
}

.equation-bar.hidden {
    display: none;
}

/* Controls */
.controls-panel {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border: 2px solid var(--text-main);
    background-color: var(--surface);
    color: var(--text-main);
    font-family: inherit;
    font-weight: 800;
    font-size: 1rem;
    cursor: pointer;
    text-align: center;
    transition: all 0.1s ease;
    text-decoration: none;
}

.btn:active {
    transform: translate(2px, 2px);
    box-shadow: 0px 0px 0px var(--text-main) !important;
}

.btn-bold {
    background-color: var(--accent-yellow);
    box-shadow: 4px 4px 0px var(--text-main);
    width: 100%;
}
.btn-bold:hover { background-color: #FCD34D; }

.btn-action {
    background-color: var(--accent-blue);
    color: white;
    box-shadow: 4px 4px 0px var(--text-main);
    width: 100%;
}
.btn-action:hover { background-color: #3B82F6; }

.file-input { display: none; }
#fileName { display: block; margin-top: 4px; font-size: 0.85rem; color: var(--text-muted); word-break: break-all;}

/* Presets Gallery */
.presets-section label {
    font-weight: 600;
    display: block;
    margin-bottom: 8px;
}
.presets-gallery {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    padding-bottom: 8px;
}
.presets-gallery::-webkit-scrollbar { height: 8px; }
.presets-gallery::-webkit-scrollbar-thumb { background: var(--border-color); border-radius: 4px;}

.preset-img {
    width: 50px;
    height: 50px;
    border: 2px solid var(--border-color);
    background: white;
    cursor: pointer;
    object-fit: contain;
    flex-shrink: 0;
    transition: border-color 0.1s;
}
.preset-img:hover {
    border-color: var(--accent-blue);
}

/* Sliders */
.control-group {
    background: #F9FAFB;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    margin-bottom: 12px;
}

.control-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-weight: 600;
}

.value-display {
    font-family: 'Space Mono', monospace;
    color: var(--accent-blue);
}

.slider {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 8px;
    background: var(--border-color);
    outline: none;
    border-radius: 4px;
    margin-bottom: 4px;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--accent-blue);
    border: 2px solid var(--text-main);
    cursor: pointer;
    border-radius: 50%;
}

.slider:disabled::-webkit-slider-thumb { background: #9CA3AF; cursor: not-allowed; }

.control-group small {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Math Explainer Box */
.math-explainer {
    height: 100%;
}

.explainer-box {
    background-color: var(--surface);
    border: 3px solid var(--text-main);
    padding: var(--spacing-md);
    border-radius: 8px;
    box-shadow: 4px 4px 0px var(--text-main);
    height: 100%;
}

.explainer-box h3 {
    color: var(--accent-blue);
    border-bottom: 2px solid var(--accent-blue);
    padding-bottom: 8px;
    margin-bottom: var(--spacing-md);
    display: inline-block;
}

/* Footer */
.footer {
    background-color: var(--text-main);
    color: var(--surface);
    padding: 2rem 0;
    margin-top: 4rem;
    border-top: 4px solid var(--accent-blue);
}
.footer p {
    color: var(--surface);
    margin: 0;
    font-family: 'Space Mono', monospace;
    font-size: 0.9rem;
}