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

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f6f9;
    color: #333;
}

.container {
    width: 90%;
    max-width: 900px;
    margin: 40px auto;
}

.header {
    margin-bottom: 20px;
}

.header h1 {
    font-size: 32px;
    font-weight: 700;
    color: #222;
}

.card {
    background: #fff;
    border-radius: 10px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.card h2 {
    margin-bottom: 15px;
    font-size: 18px;
    color: #444;
}

.button-group {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

button {
    border: none;
    border-radius: 6px;
    padding: 10px 18px;
    font-size: 15px;
    cursor: pointer;
    transition: 0.2s ease;
    background: #e0e0e0;
    color: #333;
}

button:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

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

.primary-button {
    width: 100%;
    background: #1976d2;
    color: white;
    font-size: 16px;
    font-weight: bold;
}

.primary-button:hover {
    background: #1565c0;
}

#loadSample1 {
    background: #4caf50;
    color: white;
}

#loadSample2 {
    background: #ff9800;
    color: white;
}

#clearData {
    background: #f44336;
    color: white;
}

textarea {
    width: 100%;
    min-height: 220px;
    resize: vertical;
    padding: 12px;
    border: 1px solid #ccc;
    border-radius: 6px;
    font-size: 15px;
    font-family: Consolas, Monaco, monospace;
    line-height: 1.5;
    outline: none;
    transition: 0.2s;
    background: #fafafa;
}

textarea:focus {
    border-color: #1976d2;
    box-shadow: 0 0 0 3px rgba(25, 118, 210, 0.15);
    background: #fff;
}

@media (max-width: 600px) {

    .container {
        width: 95%;
        margin: 20px auto;
    }

    .button-group {
        flex-direction: column;
    }

    .button-group button {
        width: 100%;
    }

    textarea {
        min-height: 180px;
    }

}