:root {
    --bg-color: #f4f7f6;
    --text-color: #2c3e50;
    --accent-color: #4834d4;
    --accent-hover: #686de0;
    --white: #ffffff;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    --radius: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.8;
    margin: 0;
    padding-bottom: 80px;
}

main {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

h1 {
    font-weight: 800;
    font-size: 2.5rem;
    text-align: center;
    margin-top: 40px;
    color: #130f40;
}

h3 {
    margin-top: 40px;
    font-weight: 700;
    color: var(--accent-color);
}

nav {
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    width: 100%;
    z-index: 1000;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
    padding: 15px 0;
    text-align: center;
    border-bottom: 1px solid rgba(0,0,0,0.05);
}

nav hr {
    display: none;
}

nav a {
    text-decoration: none;
    color: #2c3e50;
    font-weight: 600;
    font-size: 1rem;
    padding: 10px 20px;
    margin: 0 5px;
    border-radius: 50px;
    transition: all 0.3s ease;
    display: inline-block;
}

nav a:hover {
    color: var(--accent-color);
    background-color: rgba(72, 52, 212, 0.1);
}

img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    display: block;
    margin: 30px auto;
}

ul {
    background: var(--white);
    padding: 30px 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    list-style: none;
}

ul li {
    margin-bottom: 15px;
    padding-left: 20px;
    position: relative;
}

ul li::before {
    content: "•";
    color: var(--accent-color);
    font-weight: bold;
    font-size: 1.5rem;
    position: absolute;
    left: 0;
    top: -5px;
}

a[href*="youtube.com"] {
    display: block;
    background-color: #ff0000;
    color: white;
    text-decoration: none;
    text-align: center;
    padding: 15px;
    border-radius: var(--radius);
    font-weight: bold;
    margin: 20px 0;
    transition: transform 0.2s;
    box-shadow: 0 5px 15px rgba(255, 0, 0, 0.3);
}

a[href*="youtube.com"]:hover {
    transform: translateY(-2px);
    background-color: #e60000;
}

.quiz-container {
    background: var(--white);
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--shadow);
    margin-top: 60px;
    border: 1px solid rgba(0,0,0,0.03);
}

.quiz-container h3 {
    text-align: center;
    margin-top: 0;
    margin-bottom: 30px;
    color: #2d3436;
}

.question p {
    font-size: 1.1rem;
    font-weight: 600;
}

.options label {
    display: block;
    background: #fdfdfd;
    border: 2px solid #ecf0f1;
    padding: 15px 20px;
    border-radius: 12px;
    margin-bottom: 10px;
    cursor: pointer;
    transition: all 0.2s;
}

.options label:hover {
    border-color: var(--accent-color);
    background: #f4f3ff;
}

.quiz-btn {
    background: var(--accent-color);
    color: white;
    border: none;
    width: 100%;
    padding: 16px;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    margin-top: 20px;
    transition: transform 0.2s, background 0.3s;
    box-shadow: 0 8px 20px rgba(72, 52, 212, 0.4);
}

.quiz-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
}

.result-message {
    margin-top: 20px;
    text-align: center;
    padding: 15px;
    border-radius: 10px;
    font-weight: 600;
}

.bottom-nav {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 60px;
}

.nav-btn {
    text-decoration: none;
    padding: 14px 35px;
    border-radius: 50px;
    font-weight: 700;
    transition: all 0.3s;
}

.btn-home {
    background: transparent;
    color: #95a5a6;
    border: 2px solid #bdc3c7;
}

.btn-home:hover {
    border-color: var(--text-color);
    color: var(--text-color);
}

.btn-next {
    background: var(--text-color);
    color: white;
    box-shadow: 0 5px 15px rgba(44, 62, 80, 0.3);
}

.btn-next:hover {
    background: black;
    transform: translateY(-3px);
}
.intro {
    font-size: 1.4rem;  
    font-weight: 500;   
    text-align: center; 
    color: var(--text-color);
    margin-bottom: 40px; 
    line-height: 1.6;
}