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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: #f5f5f5;
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

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

.main-content {
    display: flex;
    gap: 20px;
    align-items: stretch;
    min-height: 500px;
}

.textbox-container {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.textbox-container label {
    font-weight: 600;
    color: #555;
    margin-bottom: 8px;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

textarea {
    flex: 1;
    padding: 15px;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 14px;
    border: 2px solid #ddd;
    border-radius: 8px;
    resize: none;
    background-color: #fff;
    transition: border-color 0.2s, box-shadow 0.2s;
}

textarea:focus {
    outline: none;
    border-color: #4a90d9;
    box-shadow: 0 0 0 3px rgba(74, 144, 217, 0.1);
}

textarea[readonly] {
    background-color: #fafafa;
}

.buttons-container {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 12px;
    padding: 20px 10px;
}

button {
    padding: 12px 24px;
    font-size: 14px;
    font-weight: 600;
    color: #fff;
    background-color: #4a90d9;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    white-space: nowrap;
}

button:hover {
    background-color: #357abd;
}

button:active {
    transform: scale(0.98);
}

button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    background-color: #9aa0a6 !important;
    color: #ffffff;
}

button:disabled:hover {
    background-color: #9aa0a6 !important;
}

button:disabled:active {
    transform: none;
}

#btn-clear {
    background-color: #e74c3c;
}

#btn-clear:hover {
    background-color: #c0392b;
}

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

#btn-copy:hover {
    background-color: #1e8449;
}

@media (max-width: 900px) {
    .main-content {
        flex-direction: column;
    }
    
    .buttons-container {
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    textarea {
        min-height: 200px;
    }
}

.footer-info {
    text-align: center;
    margin-top: 30px;
    padding: 20px;
    color: #666;
    font-size: 0.9rem;
}