body {
    max-width: 900px;
    font-family: 'Verdana', sans-serif;
    color: #464646;
    margin: 0 auto 60px;
}

a {
    color: #1976d2;
}

.homeLink {
    position: fixed;
    top: 16px;
    right: 16px;
    color: #1976d2;
    text-decoration: none;
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 4px;
    opacity: 0.7;
    transition: opacity 0.15s;
    z-index: 10;
}
.homeLink:hover {
    opacity: 1;
}

.hero {
    text-align: center;
    padding: 8px 0 4px;
}
.hero .material-icons {
    font-size: 44px;
    color: #1976d2;
}
.hero .headLine {
    margin: 0;
}

.headLine2,
.headLine3,
.headLine4 {
    color: #202020;
    text-align: left;
    border-bottom: 2px solid #1976d2;
    display: inline-block;
    padding: 0 0 4px 0;
    margin: 24px 8px 14px;
}
.headLine2 {
    font-size: 22px;
}
.headLine3 {
    font-size: 18px;
}
.headLine4 {
    font-size: 15px;
    font-weight: bold;
    border-bottom: none;
    border-left: 3px solid #1976d2;
    padding: 0 0 0 8px;
    margin: 20px 8px 10px;
}

.card {
    background: #fafafa;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    padding: 16px 20px;
    margin: 12px 8px;
    line-height: 1.7;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}
.cardAccent {
    border-left: 4px solid #1976d2;
}
.cardList {
    background: #fafafa;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    padding: 12px 18px;
    margin: 10px 8px;
    line-height: 1.7;
    transition: border-color 0.15s;
}
.cardList:hover {
    border-color: #1976d2;
}
.cardList b:first-child {
    color: #1976d2;
}

.abstractCard {
    background: #fafafa;
    border: 1px solid #e0e0e0;
    border-left: 4px solid #1976d2;
    border-radius: 10px;
    padding: 18px 22px;
    margin: 16px 8px 28px;
    line-height: 1.7;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.sectionTitle {
    font-size: 20px;
    color: #202020;
    padding: 0 8px;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.sectionTitle .material-icons {
    color: #1976d2;
    font-size: 22px;
}

.sections {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    padding: 8px;
}
.secCard {
    background: #fafafa;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    padding: 12px 16px;
    display: flex;
    gap: 12px;
    align-items: flex-start;
    transition: box-shadow 0.15s, border-color 0.15s;
}
.secCard:hover {
    border-color: #1976d2;
    box-shadow: 0 2px 6px rgba(25, 118, 210, 0.15);
}
.secNum {
    flex-shrink: 0;
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: #1976d2;
    color: #fff;
    font-size: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 2px;
}
.secCard a {
    color: #464646;
    text-decoration: none;
    font-weight: bold;
    transition: color 0.15s;
}
.secCard a:hover {
    color: #1976d2;
}
.secCard a:focus-visible {
    outline: 2px solid #1976d2;
    outline-offset: 2px;
    border-radius: 2px;
}
.secDesc {
    color: #757575;
    font-size: 13px;
    margin-top: 2px;
    line-height: 1.5;
}

.highlight {
    padding: 12px 16px;
    margin: 16px 8px;
    font-weight: bold;
    text-align: center;
    background: #e8f0fe;
    color: #1976d2;
    border: 1px solid #c5d9f5;
    border-radius: 10px;
}

.rightImage {
    float: right;
    width: 180px;
    padding: 8px;
    margin: 0 0 8px 16px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.rightImageLarge {
    float: right;
    width: 360px;
    padding: 8px;
    margin: 0 0 8px 16px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.insertImage {
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    background: #fafafa;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.optionalParagraph {
    background: #fafafa;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    padding: 12px 18px;
    margin: 12px 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.legendBox {
    float: right;
    width: 220px;
    background: #fafafa;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    padding: 8px 14px;
    margin: 0 8px 8px 16px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.borderBox {
    border: 1px solid #e0e0e0;
    background: #fff;
    border-radius: 8px;
    display: inline-block;
    padding: 10px 20px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

.insertActivity {
    float: right;
    padding: 10px;
    margin: 10px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    background: #fafafa;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.videoGrid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    padding: 20px 8px;
}

.videoCard {
    background: #fafafa;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    padding: 10px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.video-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%;
    height: 0;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
    border-radius: 6px;
}

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