:root {
–primary-color: #4a6da7;
–secondary-color: #6c757d;
–accent-color: #ffc107;
–text-color: #333;
–background-color: #f8f9fa;
–card-background: #fff;
–border-color: #dee2e6;
–success-color: #28a745;
–warning-color: #dc3545;
}

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

body {
font-family: ‘Segoe UI’, Tahoma, Geneva, Verdana, sans-serif;
line-height: 1.6;
color: var(–text-color);
background-color: var(–background-color);
padding: 20px;
}

.container {
max-width: 1200px;
margin: 0 auto;
padding: 20px;
background-color: var(–card-background);
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

h1, h2, h3, h4 {
color: var(–primary-color);
margin-bottom: 15px;
border-bottom: 2px solid var(–border-color);
padding-bottom: 10px;
}

h1 {
font-size: 2.5rem;
text-align: center;
margin-bottom: 30px;
}

h2 {
font-size: 1.8rem;
margin-top: 30px;
}

h3 {
font-size: 1.4rem;
margin-top: 25px;
border-bottom: 1px solid var(–border-color);
}

p {
margin-bottom: 20px;
}

ul, ol {
margin-bottom: 20px;
padding-left: 30px;
}

li {
margin-bottom: 10px;
}

.image-container {
text-align: center;
margin: 20px 0;
position: relative;
}

.image-container img {
max-width: 100%;
height: auto;
border-radius: 8px;
box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.image-fallback {
padding: 20px;
background-color: #f2f2f2;
border: 2px dashed #ccc;
border-radius: 8px;
text-align: center;
margin: 20px 0;
color: #666;
}

.code-block {
background-color: #272822;
color: #f8f8f2;
padding: 15px;
border-radius: 5px;
font-family: ‘Courier New’, Courier, monospace;
margin-bottom: 20px;
overflow-x: auto;
}

.note {
background-color: #fff3cd;
border-left: 4px solid var(–accent-color);
padding: 15px;
margin-bottom: 20px;
border-radius: 4px;
}

.tip {
background-color: #d4edda;
border-left: 4px solid var(–success-color);
padding: 15px;
margin-bottom: 20px;
border-radius: 4px;
}

.warning {
background-color: #f8d7da;
border-left: 4px solid var(–warning-color);
padding: 15px;
margin-bottom: 20px;
border-radius: 4px;
}

.resource-card {
border: 1px solid var(–border-color);
border-radius: 8px;
padding: 15px;
margin-bottom: 20px;
transition: transform 0.3s ease;
background-color: var(–card-background);
}

.resource-card:hover {
transform: translateY(-5px);
box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.exercise {
background-color: #e6f3ff;
border-radius: 8px;
padding: 20px;
margin: 30px 0;
border-left: 5px solid var(–primary-color);
}

.video-container {
position: relative;
padding-bottom: 56.25%; /* 16:9 Aspect Ratio */
height: 0;
overflow: hidden;
margin-bottom: 20px;
border-radius: 8px;
box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.video-container iframe {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
border: none;
}

.video-fallback {
padding: 30px;
background-color: #f2f2f2;
border: 2px dashed #ccc;
border-radius: 8px;
text-align: center;
margin: 20px 0;
color: #666;
}

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

table, th, td {
border: 1px solid var(–border-color);
}

th {
background-color: var(–primary-color);
color: white;
padding: 12px;
text-align: left;
}

td {
padding: 12px;
}

tr:nth-child(even) {
background-color: #f2f2f2;
}

@media (max-width: 768px) {
.container {
padding: 10px;
}

h1 {
font-size: 2rem;
}

h2 {
font-size: 1.5rem;
}

h3 {
font-size: 1.2rem;
}
}