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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 750px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    padding: 8px;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 2em;
}

h3 {
    color: #555;
    margin-bottom: 15px;
    font-size: 1.2em;
}

h4 {
    color: #666;
    margin-bottom: 10px;
    font-size: 1em;
}

/* Controls */
.controls {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-bottom: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 8px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group label {
    font-weight: 600;
    color: #555;
    font-size: 0.9em;
}

select, input[type="number"] {
    padding: 8px 12px;
    border: 2px solid #ddd;
    border-radius: 6px;
    font-size: 1em;
    background: white;
    cursor: pointer;
    transition: border-color 0.3s;
}

select:hover, input[type="number"]:hover {
    border-color: #667eea;
}

select:focus, input[type="number"]:focus {
    outline: none;
    border-color: #667eea;
}

/* Toggle button */
.toggle-btn {
    width: 100%;
    margin-top: 15px;
    padding: 10px 20px;
    border: 2px solid #667eea;
    border-radius: 6px;
    background: white;
    color: #667eea;
    font-size: 0.95em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-align: left;
}

.toggle-btn:hover {
    background: #667eea;
    color: white;
}

/* Character Grid */
#character-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(40px, 1fr));
    gap: 5px;
    max-width: 100%;
    margin-top: 10px;
    max-height: 500px;
    overflow-y: auto;
    transition: max-height 0.3s ease, opacity 0.3s ease;
    opacity: 1;
}

#character-grid.collapsed {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    margin-top: 0;
}

.char-grid-break {
    grid-column: 1 / -1;
    height: 10px;
}

.char-btn {
    width: 40px;
    height: 40px;
    border: 2px solid #ddd;
    border-radius: 4px;
    background: white;
    font-size: 1.1em;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    color: #333;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.char-btn.control-char {
    font-size: 0.8em;
    color: #999;
}

.char-btn:hover {
    background: #667eea;
    color: white;
    border-color: #667eea;
    transform: scale(1.05);
}

.char-btn.active {
    background: #667eea;
    color: white;
    border-color: #5568d3;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.3);
}

/* Editor Section */
.editor-section {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 30px;
    margin-bottom: 30px;
}

@media (max-width: 968px) {
    .editor-section {
        grid-template-columns: 1fr;
    }
}

/* Matrix Panel */
.matrix-panel {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
}

#matrix-container {
    display: inline-grid;
    gap: 2px;
    padding: 15px;
    background: white;
    border: 2px solid #ddd;
    border-radius: 6px;
    margin-bottom: 15px;
}

.pixel {
    width: 30px;
    height: 30px;
    border: 1px solid #ccc;
    cursor: pointer;
    transition: all 0.1s;
    border-radius: 2px;
}

.pixel.off {
    background: white;
}

.pixel.on {
    background: #333;
}

.pixel:hover {
    transform: scale(1.1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.matrix-controls {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

/* Buttons */
button {
    padding: 10px 20px;
    border: none;
    border-radius: 6px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    color: white;
}

#undo-btn {
    background: #3498db;
}

#undo-btn:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.4);
}

#redo-btn {
    background: #9b59b6;
}

#redo-btn:hover {
    background: #8e44ad;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(155, 89, 182, 0.4);
}

#reset-btn {
    background: #e74c3c;
}

#reset-btn:hover {
    background: #c0392b;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(231, 76, 60, 0.4);
}

#copy-hex-btn {
    background: #27ae60;
}

#copy-hex-btn:hover {
    background: #229954;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(39, 174, 96, 0.4);
}

#export-c-btn, #export-json-btn {
    background: #667eea;
}

#export-c-btn:hover, #export-json-btn:hover {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

button:active {
    transform: translateY(0);
}

/* Data Section */
.data-section {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
}

.data-display {
    margin-bottom: 15px;
}

.hex-data, .binary-data {
    background: white;
    padding: 15px;
    border-radius: 6px;
    border: 2px solid #ddd;
}

code {
    display: block;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    color: #333;
    white-space: pre-wrap;
    word-break: break-all;
}

/* Export Section */
.export-section {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}