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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    margin: 0;
    padding: 0;
    background: black;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Hide UI elements in background mode */
body.background-mode #controls,
body.background-mode #aboutPanel {
    display: none !important;
}

#canvas {
    display: block;
    width: 100vw;
    height: 100vh;
    background: black;
}

#controls {
    position: fixed;
    top: 20px;
    right: 20px;
    background: rgba(0, 0, 0, 0.8);
    border: 1px solid #444;
    border-radius: 8px;
    padding: 15px;
    color: white;
    font-family: 'Arial', sans-serif;
    backdrop-filter: blur(10px);
    z-index: 1000;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.control-group:last-child {
    margin-bottom: 0;
}

.control-group label {
    font-size: 14px;
    font-weight: bold;
    min-width: 50px;
}

.control-group button {
    background: #333;
    border: 1px solid #555;
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s;
}

.control-group button:hover {
    background: #555;
}

.control-group button:active {
    background: #666;
}

#pointCountDisplay {
    font-size: 14px;
    font-weight: bold;
    min-width: 25px;
    text-align: center;
}

#distanceMetric {
    background: #333;
    border: 1px solid #555;
    color: white;
    padding: 5px 8px;
    border-radius: 4px;
    font-size: 12px;
    cursor: pointer;
    min-width: 120px;
}

#distanceMetric:focus {
    outline: none;
    border-color: #777;
}

#distanceMetric option {
    background: #333;
    color: white;
}

.control-group label {
    display: flex;
    align-items: center;
    gap: 5px;
    cursor: pointer;
    user-select: none;
}

.control-group input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: #666;
}

#pausePlay {
    background: #444;
    border: 1px solid #666;
    color: white;
    padding: 8px 16px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 12px;
    transition: background-color 0.2s;
}

#pausePlay:hover {
    background: #555;
}

#pausePlay:active {
    background: #666;
}

input[type="range"] {
    width: 80px;
    height: 4px;
    background: #444;
    outline: none;
    border-radius: 2px;
    appearance: none;
    margin: 0 5px;
}

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 16px;
    height: 16px;
    background: #666;
    border-radius: 50%;
    cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
    width: 16px;
    height: 16px;
    background: #666;
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

#gradientValue {
    font-size: 12px;
    color: #ccc;
    min-width: 25px;
    text-align: center;
}

#aboutPanel {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1000;
}

#aboutButton {
    background: rgba(68, 68, 68, 0.9);
    border: 1px solid #666;
    color: white;
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s ease;
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

#aboutButton:hover {
    background: rgba(85, 85, 85, 0.9);
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.4);
}

#aboutButton:active {
    background: rgba(102, 102, 102, 0.9);
    transform: translateY(0);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(5px);
}

.modal-content {
    background-color: #1a1a1a;
    margin: 5% auto;
    padding: 30px;
    border: 1px solid #444;
    border-radius: 12px;
    width: 80%;
    max-width: 800px;
    max-height: 80vh;
    overflow-y: auto;
    color: white;
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
}

.close {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    line-height: 1;
}

.close:hover,
.close:focus {
    color: white;
}

.modal-content h2 {
    color: #fff;
    margin-top: 0;
    border-bottom: 2px solid #444;
    padding-bottom: 10px;
}

.modal-content h3 {
    color: #ddd;
    margin-top: 25px;
    margin-bottom: 15px;
}

.modal-content h4 {
    color: #ccc;
    margin-top: 20px;
    margin-bottom: 10px;
}

.modal-content p {
    margin: 10px 0;
    color: #bbb;
}

.modal-content .math-block {
    background: #2a2a2a;
    padding: 15px;
    border-radius: 6px;
    border-left: 3px solid #666;
    margin: 20px 0;
    text-align: center;
    overflow-x: auto;
}

.modal-content .math-inline {
    background: #2a2a2a;
    padding: 2px 6px;
    border-radius: 3px;
    margin: 0 2px;
}

/* KaTeX styling adjustments for dark theme */
.modal-content .katex {
    color: #fff !important;
}

.modal-content .katex .base {
    color: #fff !important;
}

.modal-content .katex .mord, 
.modal-content .katex .mop, 
.modal-content .katex .mbin, 
.modal-content .katex .mrel, 
.modal-content .katex .mopen, 
.modal-content .katex .mclose, 
.modal-content .katex .mpunct {
    color: #fff !important;
}

.modal-content .metric {
    background: #222;
    padding: 15px;
    margin: 15px 0;
    border-radius: 8px;
    border-left: 4px solid #555;
}

.modal-content ul {
    margin: 10px 0;
    padding-left: 20px;
}

.modal-content li {
    margin: 5px 0;
    color: #bbb;
}

.modal-content em {
    font-style: italic;
    color: #ddd;
}

.modal-content strong {
    color: #fff;
    font-weight: bold;
}