Вот полная, структурированная HTML-страница для школьного справочника по теме «Деление инфузории». Материал подготовлен с учетом возрастных особенностей и требований наглядности.

«`html

body {
font-family: ‘Segoe UI’, Tahoma, Geneva, Verdana, sans-serif;
background-color:

f4f7f6;

margin: 0;
padding: 20px;
color:

1a1a2e;

line-height: 1.6;
}
.container {
max-width: 960px;
margin: 0 auto;
background: white;
padding: 30px 35px;
border-radius: 16px;
box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}
h1 {
font-size: 2.2em;
color:

0f3460;

border-bottom: 4px solid

e94560;

padding-bottom: 10px;
margin-top: 0;
}
h2 {
font-size: 1.6em;
color:

16213e;

margin-top: 30px;
border-left: 6px solid

e94560;

padding-left: 15px;
}
h3 {
font-size: 1.3em;
color:

0f3460;

margin-top: 20px;
}
p {
margin: 0 0 15px 0;
}
.analogy-box {
background:

e8f4f8;

border-left: 6px solid

00b4d8;

padding: 15px 20px;
border-radius: 8px;
margin: 20px 0;
font-style: italic;
}
.step-list {
background:

f9f9f9;

padding: 15px 25px;
border-radius: 10px;
list-style-type: none;
counter-reset: step;
}
.step-list li {
counter-increment: step;
margin-bottom: 12px;
padding-left: 40px;
position: relative;
}
.step-list li::before {
content: counter(step);
background:

e94560;

color: white;
font-weight: bold;
width: 28px;
height: 28px;
border-radius: 50%;
display: inline-flex;
align-items: center;
justify-content: center;
position: absolute;
left: 0;
top: 2px;
font-size: 0.9em;
}
table.shpargalka {
width: 100%;
border-collapse: collapse;
margin: 20px 0;
font-size: 1em;
box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}
table.shpargalka th {
background-color:

0f3460;

color: white;
padding: 12px 15px;
text-align: left;
font-weight: 600;
}
table.shpargalka td {
padding: 12px 15px;
border-bottom: 1px solid

ddd;

vertical-align: top;
}
table.shpargalka tr:nth-child(even) {
background-color:

f2f2f2;

}
.example-block {
background:

fef9e7;

border-left: 6px solid

f39c12;

padding: 15px 20px;
margin: 20px 0;
border-radius: 8px;
}
.example-block strong {
color:

c0392b;

}
.parent-check {
background:

eafaf1;

border-left: 6px solid

27ae60;

padding: 15px 20px;
border-radius: 8px;
}
.error-list {
background:

fdedec;

border-left: 6px solid

e74c3c;

padding: 15px 20px;
border-radius: 8px;
}
.error-list li {
margin-bottom: 10px;
}
.footer-note {
margin-top: 30px;
padding-top: 15px;
border-top: 2px dashed

ccc;

text-align: center;
color:

555;

font-size: 0.9em;
}
.math-symbol {
font-family: ‘Times New Roman’, serif;
font-size: 1.2em;
}

«`