header {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px;
    background: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
    color: white;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

.content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

@media (max-width: 768px) {
    .content {
        grid-template-columns: 1fr;
    }
}

.section {
    background: white;
    border-radius: 10px;
    padding: 25px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
    margin-bottom: 30px;
}

h2 {
    color: #2575fc;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #f0f0f0;
}

h3 {
    color: #6a11cb;
    margin: 20px 0 10px;
}

p {
    margin-bottom: 15px;
}

.code-block {
    background: #2d2d2d;
    color: #f8f8f2;
    padding: 15px;
    border-radius: 5px;
    margin: 15px 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
}

.tag {
    color: #f92672;
}

.attribute {
    color: #a6e22e;
}

.value {
    color: #e6db74;
}

.comment {
    color: #75715e;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

table, th, td {
    border: 1px solid #ddd;
}

th {
    background-color: #f2f2f2;
    padding: 12px 15px;
    text-align: left;
}

td {
    padding: 10px 15px;
}

.example-table {
    background: white;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.example-table th {
    background: #2575fc;
    color: white;
}

.example-table tr:nth-child(even) {
    background: #f9f9f9;
}

.preview {
    background: #f9f9f9;
    padding: 20px;
    border-radius: 5px;
    border-left: 4px solid #2575fc;
}

.note {
    background: #fff9e6;
    padding: 15px;
    border-left: 4px solid #ffc107;
    margin: 20px 0;
}

.exercise {
    background: #e8f5e9;
    padding: 20px;
    border-radius: 5px;
    margin: 25px 0;
}

/*footer {
    text-align: center;
    margin-top: 50px;
    padding: 20px;
    color: #666;
    font-size: 0.9rem;
}*/

/*.btn {*/
/*    display: inline-block;*/
/*    background: #2575fc;*/
/*    color: white;*/
/*    padding: 10px 20px;*/
/*    border-radius: 5px;*/
/*    text-decoration: none;*/
/*    margin-top: 10px;*/
/*    transition: background 0.3s;*/
/*}*/

.btn:hover {
    background: #1a68e8;
}