:root {
    --background-color: #121212;
    --text-color: #FFFFFF;
    --text-muted: #B0B0B0;
    --header-background: #1A1A1A;
    --header-text-color: #FFFFFF;
    --nav-link-color: #E0E0E0;
    --nav-link-hover-color: #B0B0B0;
    --welcome-section-bg: #1C1C1C;
    --card-bg: #1A1A1A;
    --card-hover-bg: #222222;
    --topic-card-text-color: #FFFFFF;
    --btn-bg: #E0E0E0;
    --btn-hover-bg: #B0B0B0;
    --info-item-bg: #1A1A1A;
    --footer-bg: #1C1C1C;
    --footer-text: #B0B0B0;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

header {
    background-color: var(--header-background);
    padding: 40px;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

header h1 {
    font-size: 3rem;
    color: var(--header-text-color);
    letter-spacing: 2px;
}

nav {margin-top: 15px;}

nav a {
    color: var(--nav-link-color);
    text-decoration: none;
    margin: 0 25px;
    font-size: 1.2rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.3s ease;
}

nav a:hover {color: var(--nav-link-hover-color);}

.main-container {padding: 60px 20px;}

.welcome-section {
    text-align: center;
    margin-bottom: 60px;
    padding: 40px;
    background-color: var(--welcome-section-bg);
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.welcome-section h2 {
    font-size: 2.6rem;
    color: var(--header-text-color);
    margin-bottom: 15px;
}

.welcome-section p {
    font-size: 1.2rem;
    color: var(--text-muted);
}

.content-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 20px;
    margin-top: 60px;
}

img {
    width: 200px;
    margin-left: auto;
    margin-right: auto;
}

.card {
    background-color: var(--card-bg);
    padding: 30px;
    border-radius: 10px;
    transition: transform 0.3s ease, background-color 0.3s;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.card:hover {
    transform: translateY(-10px);
    background-color: var(--card-hover-bg);
}

.card h3 {
    font-size: 1.8rem;
    color: var(--topic-card-text-color);
    margin-bottom: 15px;
}

.card p {
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 25px;
}

.card .btn {
    padding: 12px 25px;
    background-color: var(--btn-bg);
    color: black;
    font-size: 1.1rem;
    text-decoration: none;
    border-radius: 5px;
    transition: background-color 0.3s;
}

.card .btn:hover {
    background-color: var(--btn-hover-bg);
}

.iframe-container {
    margin-top: 60px;
    text-align: center;
}

.iframe-container iframe {
    border: none;
    width: 80%;
    height: 450px;
    border-radius: 8px;
}

.info-panel {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 60px;
}

.info-item {
    background-color: var(--info-item-bg);
    padding: 30px;
    border-radius: 10px;
    transition: transform 0.3s ease, background-color 0.3s;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    text-align: center;
}

.info-item:hover {
    transform: translateY(-10px);
    background-color: var(--card-hover-bg);
}

.info-item h3 {
    font-size: 1.8rem;
    color: var(--topic-card-text-color); 
    margin-bottom: 15px;
}

.info-item p {
    color: var(--text-muted);
    font-size: 1rem;
}

footer {
    background-color: var(--footer-bg);
    padding: 30px;
    text-align: center;
    margin-top: 60px;
    box-shadow: 0 -4px 15px rgba(0, 0, 0, 0.2);
}

footer p {
    color: var(--footer-text);
    font-size: 1rem;
}

@media (max-width: 768px) {
    .welcome-section h2 {font-size: 2.2rem;}
    .content-cards {grid-template-columns: 1fr;}
    .card h3 {font-size: 1.6rem;}
    .card p {font-size: 1rem;}
}