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

body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background-color: #FAFAFA;
    color: #5A6B7C;
    line-height: 1.7;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 20px;
}

header {
    text-align: center;
    margin-bottom: 50px;
    padding-bottom: 30px;
    border-bottom: 1px solid #E0E0E0;
}

header h1 {
    font-size: 2.2rem;
    font-weight: 400;
    color: #1A73E8;
    margin-bottom: 15px;
}

header .subtitle {
    font-size: 1rem;
    color: #7A8A9C;
    max-width: 700px;
    margin: 0 auto 25px;
}

.course-info {
    background: white;
    padding: 25px;
    border-radius: 8px;
    margin-bottom: 30px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.course-info h2 {
    font-size: 1.3rem;
    font-weight: 500;
    color: #1A73E8;
    margin-bottom: 15px;
}

.course-info p {
    margin-bottom: 12px;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

.info-item {
    padding: 12px;
    background: #F8F9FA;
    border-radius: 6px;
    font-size: 0.9rem;
}

.info-item strong {
    color: #1A73E8;
    display: block;
    margin-bottom: 5px;
}

.section {
    background: white;
    padding: 30px;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.section:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.section-header {
    display: flex;
    align-items: center;
    margin-bottom: 15px;
}

.section-number {
    font-size: 1.8rem;
    font-weight: 300;
    color: #1A73E8;
    margin-right: 15px;
    min-width: 40px;
}

.section h3 {
    font-size: 1.4rem;
    font-weight: 500;
    color: #2C3E50;
}

.section p {
    margin-bottom: 15px;
}

.topics-list {
    background: #F8F9FA;
    padding: 20px;
    border-radius: 6px;
    margin: 15px 0;
}

.topics-list h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: #1A73E8;
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.topics-list ul {
    list-style: none;
    padding-left: 0;
}

.topics-list li {
    padding: 6px 0 6px 20px;
    position: relative;
    font-size: 0.95rem;
}

.topics-list li:before {
    content: "▪";
    position: absolute;
    left: 0;
    color: #1A73E8;
}

.practice {
    background: #E3F2FD;
    padding: 15px 20px;
    border-radius: 6px;
    border-left: 4px solid #1A73E8;
    margin-top: 15px;
}

.practice strong {
    color: #1A73E8;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.final-project {
    background: linear-gradient(135deg, #1A73E8 0%, #0d5dc1 100%);
    color: white;
    padding: 40px;
    border-radius: 8px;
    text-align: center;
    margin-top: 30px;
}

.final-project h3 {
    font-size: 1.8rem;
    font-weight: 400;
    margin-bottom: 15px;
}

.final-project p {
    font-size: 1.05rem;
    line-height: 1.8;
    opacity: 0.95;
}

.back-button {
    display: inline-block;
    margin-top: 40px;
    padding: 12px 30px;
    background: white;
    color: #1A73E8;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.back-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.back-button i {
    margin-right: 8px;
}

.scroll-to-top {
    position: fixed;
    right: 30px;
    bottom: 30px;
    width: 50px;
    height: 50px;
    background: #1A73E8;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.2s ease;
    box-shadow: 0 4px 12px rgba(26, 115, 232, 0.3);
    z-index: 1000;
}

.scroll-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.scroll-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 16px rgba(26, 115, 232, 0.4);
}

.scroll-to-top i {
    font-size: 1.2rem;
}

@media (max-width: 768px) {
    .container {
        padding: 20px 15px;
    }
    
    header h1 {
        font-size: 1.8rem;
    }
    
    .section {
        padding: 20px;
    }
    
    .section-number {
        font-size: 1.5rem;
    }
    
    .scroll-to-top {
        right: 20px;
        bottom: 20px;
        width: 45px;
        height: 45px;
    }
}