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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    background-color: #f5f5f5;
    color: #333;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2c3e50;
}

.input-section, .output-section {
    margin-bottom: 1.5rem;
}

textarea {
    width: 100%;
    min-height: 150px;
    padding: 1rem;
    border: 2px solid #e0e0e0;
    border-radius: 5px;
    font-size: 1rem;
    resize: vertical;
    transition: border-color 0.3s ease;
}

textarea:focus {
    outline: none;
    border-color: #3498db;
}

.controls {
    display: flex;
    gap: 1rem;
    align-items: center;
    margin-bottom: 1.5rem;
}

.transform-option {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

input[type="text"] {
    padding: 0.5rem;
    border: 2px solid #e0e0e0;
    border-radius: 5px;
    font-size: 1rem;
    width: 60px;
    text-align: center;
}

button {
    padding: 0.75rem 1.5rem;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #2980b9;
}

#copyBtn {
    background-color: #2ecc71;
    width: 100%;
    margin-top: 0.5rem;
}

#copyBtn:hover {
    background-color: #27ae60;
}

#outputText {
    background-color: #f8f9fa;
}

.separator-history {
    margin-bottom: 1.5rem;
}

.separator-history h3 {
    margin-bottom: 0.5rem;
    color: #2c3e50;
    font-size: 1rem;
}

.separator-button-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.hex-display {
    font-family: monospace;
    font-size: 0.7rem;
    color: #666;
    background-color: #f0f0f0;
    padding: 0.1rem 0.3rem;
    border-radius: 3px;
    white-space: nowrap;
}

.separator-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.separator-button {
    padding: 0.5rem 1rem;
    background-color: #f8f9fa;
    color: #2c3e50;
    border: 1px solid #e0e0e0;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.separator-button:hover {
    background-color: #e9ecef;
    border-color: #3498db;
    transform: translateY(-1px);
}

.separator-button:active {
    transform: translateY(0);
}