diff --git a/frontend/textbooks/physics_8_ch1.html b/frontend/textbooks/physics_8_ch1.html
index 86eab96..ee4d7a8 100644
--- a/frontend/textbooks/physics_8_ch1.html
+++ b/frontend/textbooks/physics_8_ch1.html
@@ -1,4 +1,257 @@
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+  <path d="M50 8 C 52 22 65 30 64 46 C 63 56 56 60 55 48 C 53 56 48 60 42 58 C 36 56 32 50 34 42 C 30 52 22 60 24 72 C 26 84 36 92 50 92 C 64 92 76 84 76 70 C 76 50 60 40 56 22 C 54 14 52 10 50 8 Z"/>
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+  <div class="p8-hero-meter" id="p8-meter-ch1"><span id="p8-meter-val">37</span>°C</div>
+  <div class="p8-hero-inner">
+    <div class="p8-hero-eyebrow">Глава 1 · 11 параграфов</div>
+    <h1 class="p8-hero-title">Тепловые явления</h1>
+    <div class="p8-hero-sub">Внутренняя энергия, способы теплопередачи, плавление и кипение. Перетаскивайте термометры, нагреватели и материалы — наблюдайте поведение тепла в реальном времени.</div>
+    <div class="hdr-side" style="margin-top:18px;display:flex;gap:8px;flex-wrap:wrap;position:relative;z-index:1">
+      <a href="/textbook/physics-8" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><polyline points="15 18 9 12 15 6"/></svg> К физике 8</a>
+      <button id="search-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><circle cx="11" cy="11" r="7"/><path d="m21 21-4-4"/></svg> Поиск</button>
+      <button id="sidebar-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><line x1="4" y1="6" x2="20" y2="6"/><line x1="4" y1="12" x2="20" y2="12"/><line x1="4" y1="18" x2="14" y2="18"/></svg> Шпаргалка</button>
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+    </div>
+  </div>
+</header>
+
+<main class="main">
+  <div class="col-main">
+
+    <section class="hero">
+      <h2>Тепловые явления — как энергия переходит между телами</h2>
+      <p>Внутренняя энергия зависит от температуры тела. Тепло передаётся теплопроводностью, конвекцией и излучением. При нагревании, плавлении и кипении нужно разное количество теплоты.</p>
+      <div class="hero-row">
+        <button class="btn-primary" onclick="goTo('p1')"><svg class="ic" viewBox="0 0 24 24"><polygon points="6 4 20 12 6 20 6 4" fill="currentColor" stroke="none"/></svg> Начать § 1</button>
+        <div class="hero-progress">
+          <span class="hp-label">Прогресс по главе</span>
+          <div class="hp-bar"><div id="hero-hp-fill" class="hp-fill"></div></div>
+          <span id="hero-hp-text" class="hp-text">0%</span>
+        </div>
+        <div id="hero-xp-badge" class="hero-xp-badge" data-gamified></div>
+      </div>
+    </section>
+
+    <section class="psel">
+      <div class="psel-title">Параграфы главы</div>
+      <div id="psel-grid" class="psel-grid"></div>
+    </section>
+
+    <section id="sec-p1" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p1" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="28" stroke="currentColor" stroke-width="6" fill="none"/><path d="M50 22 v56 M22 50 h56" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 1</span><h2 class="sec-h">Внутренняя энергия</h2></div><div id="p1-body"></div></section>
+    <section id="sec-p2" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p2" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M50 12 v76 M50 12 l-14 16 M50 12 l14 16 M50 88 l-14-16 M50 88 l14-16" stroke="currentColor" stroke-width="4" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 2</span><h2 class="sec-h">Способы изменения внутренней энергии</h2></div><div id="p2-body"></div></section>
+    <section id="sec-p3" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p3" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M14 50 h72 M86 50 l-14-14 M86 50 l-14 14" stroke="currentColor" stroke-width="5" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 3</span><h2 class="sec-h">Теплопроводность</h2></div><div id="p3-body"></div></section>
+    <section id="sec-p4" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p4" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M30 80 C 30 50, 70 50, 70 30 M30 30 C 30 60, 70 60, 70 80" stroke="currentColor" stroke-width="4" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 4</span><h2 class="sec-h">Конвекция</h2></div><div id="p4-body"></div></section>
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+    <section id="sec-p6" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p6" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="35" width="60" height="35" rx="4" stroke="currentColor" stroke-width="4" fill="none"/><path d="M28 35 v-8 M50 35 v-8 M72 35 v-8" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 6</span><h2 class="sec-h">Расчёт количества теплоты при нагревании и охлаждении. Удельная теплоёмкость</h2></div><div id="p6-body"></div></section>
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+    <section id="sec-final1" class="sec"><div class="sec-header"><span class="sec-num">&#9733;</span><h2 class="sec-h">Финал главы</h2></div><div id="final1-body"></div></section>
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-    <h1 class="p8-hero-title">Тепловые явления</h1>
-    <div class="p8-hero-sub">Внутренняя энергия, способы теплопередачи, плавление и кипение. Перетаскивайте термометры, нагреватели и материалы — наблюдайте поведение тепла в реальном времени.</div>
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-      <p>Внутренняя энергия зависит от температуры тела. Тепло передаётся теплопроводностью, конвекцией и излучением. При нагревании, плавлении и кипении нужно разное количество теплоты.</p>
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-    <section id="sec-p6" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p6" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="35" width="60" height="35" rx="4" stroke="currentColor" stroke-width="4" fill="none"/><path d="M28 35 v-8 M50 35 v-8 M72 35 v-8" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 6</span><h2 class="sec-h">Расчёт количества теплоты при нагревании и охлаждении. Удельная теплоёмкость</h2></div><div id="p6-body"></div></section>
-    <section id="sec-p7" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p7" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M28 78 L50 22 L72 78 Z" stroke="currentColor" stroke-width="4" fill="none"/><path d="M40 60 L60 60" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 7</span><h2 class="sec-h">Горение. Удельная теплота сгорания топлива</h2></div><div id="p7-body"></div></section>
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-    <section id="sec-final1" class="sec"><div class="sec-header"><span class="sec-num">&#9733;</span><h2 class="sec-h">Финал главы</h2></div><div id="final1-body"></div></section>
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+
+.sec{transition:opacity .25s}
+</style>
+</head>
+<body class="p8-theme-electric">
+
+<header class="p8-hero">
+  <div class="p8-hero-wm"><svg viewBox="0 0 100 100" aria-hidden="true">
+  <path d="M55 8 L25 56 L46 56 L40 92 L75 38 L52 38 L60 8 Z"/>
+</svg></div>
+  <div class="p8-hero-meter" id="p8-meter-ch2"><span id="p8-meter-val">0.5</span> А</div>
+  <div class="p8-hero-inner">
+    <div class="p8-hero-eyebrow">Глава 2 · 20 параграфов</div>
+    <h1 class="p8-hero-title">Электромагнитные явления</h1>
+    <div class="p8-hero-sub">Заряд, ток, цепь, магнитное поле. Конструируйте цепи из компонентов, перемещайте заряды, наблюдайте за искрами и полями.</div>
+    <div class="hdr-side" style="margin-top:18px;display:flex;gap:8px;flex-wrap:wrap;position:relative;z-index:1">
+      <a href="/textbook/physics-8" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><polyline points="15 18 9 12 15 6"/></svg> К физике 8</a>
+      <button id="search-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><circle cx="11" cy="11" r="7"/><path d="m21 21-4-4"/></svg> Поиск</button>
+      <button id="sidebar-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><line x1="4" y1="6" x2="20" y2="6"/><line x1="4" y1="12" x2="20" y2="12"/><line x1="4" y1="18" x2="14" y2="18"/></svg> Шпаргалка</button>
+      <button id="theme-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><path d="M21 12.8A9 9 0 1 1 11.2 3a7 7 0 0 0 9.8 9.8z"/></svg><span id="theme-lab">Тёмная</span></button>
+    </div>
+  </div>
+</header>
+
+<main class="main">
+  <div class="col-main">
+
+    <section class="hero">
+      <h2>Электромагнитные явления — от заряда до магнита</h2>
+      <p>Заряды притягиваются и отталкиваются, образуют электрическое поле. По проводнику течёт ток, и закон Ома связывает $U$, $I$, $R$. У постоянных магнитов и проводников с током есть магнитное поле.</p>
+      <div class="hero-row">
+        <button class="btn-primary" onclick="goTo('p12')"><svg class="ic" viewBox="0 0 24 24"><polygon points="6 4 20 12 6 20 6 4" fill="currentColor" stroke="none"/></svg> Начать § 12</button>
+        <div class="hero-progress">
+          <span class="hp-label">Прогресс по главе</span>
+          <div class="hp-bar"><div id="hero-hp-fill" class="hp-fill"></div></div>
+          <span id="hero-hp-text" class="hp-text">0%</span>
+        </div>
+        <div id="hero-xp-badge" class="hero-xp-badge" data-gamified></div>
+      </div>
+    </section>
+
+    <section class="psel">
+      <div class="psel-title">Параграфы главы</div>
+      <div id="psel-grid" class="psel-grid"></div>
+    </section>
+
+    <section id="sec-p12" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p12" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="35" cy="50" r="14" fill="currentColor"/><circle cx="65" cy="50" r="14" fill="currentColor"/><path d="M40 50 L60 50 M50 40 L50 60" stroke="currentColor" stroke-width="3" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 12</span><h2 class="sec-h">Электризация тел. Взаимодействие зарядов</h2></div><div id="p12-body"></div></section>
+    <section id="sec-p13" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p13" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="40" width="60" height="20" fill="none" stroke="currentColor" stroke-width="4"/><circle cx="35" cy="50" r="3" fill="currentColor"/><circle cx="50" cy="50" r="3" fill="currentColor"/><circle cx="65" cy="50" r="3" fill="currentColor"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 13</span><h2 class="sec-h">Проводники и диэлектрики</h2></div><div id="p13-body"></div></section>
+    <section id="sec-p14" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p14" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="24" fill="none" stroke="currentColor" stroke-width="4"/><path d="M50 26 L50 14 M50 86 L50 74 M26 50 L14 50 M86 50 L74 50" stroke="currentColor" stroke-width="4"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 14</span><h2 class="sec-h">Электризация через влияние</h2></div><div id="p14-body"></div></section>
+    <section id="sec-p15" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p15" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="16" fill="currentColor"/><path d="M50 30 L50 18 M50 82 L50 70 M30 50 L18 50 M82 50 L70 50" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 15</span><h2 class="sec-h">Электрический заряд. Элементарный заряд</h2></div><div id="p15-body"></div></section>
+    <section id="sec-p16" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p16" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="6" fill="currentColor"/><ellipse cx="50" cy="50" rx="32" ry="14" fill="none" stroke="currentColor" stroke-width="2.5"/><ellipse cx="50" cy="50" rx="14" ry="32" fill="none" stroke="currentColor" stroke-width="2.5"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 16</span><h2 class="sec-h">Строение атома. Ионы</h2></div><div id="p16-body"></div></section>
+    <section id="sec-p17" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p17" aria-hidden="true"><svg viewBox="0 0 100 100"><line x1="20" y1="50" x2="80" y2="50" stroke="currentColor" stroke-width="3"/><line x1="20" y1="35" x2="80" y2="65" stroke="currentColor" stroke-width="3"/><line x1="20" y1="65" x2="80" y2="35" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 17</span><h2 class="sec-h">Электрическое поле. Электрическое напряжение</h2></div><div id="p17-body"></div></section>
+    <section id="sec-p18" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p18" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M30 50 L70 50" stroke="currentColor" stroke-width="5" fill="none"/><path d="M65 45 L70 50 L65 55" stroke="currentColor" stroke-width="3" fill="none"/><text x="30" y="40" font-family="Inter" font-size="14" font-weight="700" fill="currentColor">U</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 18</span><h2 class="sec-h">Единица электрического напряжения. Расчёт работы в электрическом поле</h2></div><div id="p18-body"></div></section>
+    <section id="sec-p19" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p19" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="40" width="14" height="20" fill="currentColor"/><rect x="38" y="35" width="6" height="30" fill="currentColor"/><line x1="50" y1="50" x2="80" y2="50" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 19</span><h2 class="sec-h">Электрический ток. Источники тока</h2></div><div id="p19-body"></div></section>
+    <section id="sec-p20" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p20" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M20 70 L40 30 L60 70 L80 30" stroke="currentColor" stroke-width="4" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 20</span><h2 class="sec-h">Сила и направление электрического тока</h2></div><div id="p20-body"></div></section>
+    <section id="sec-p21" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p21" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="40" width="60" height="20" fill="none" stroke="currentColor" stroke-width="3"/><path d="M30 50 L50 50 M55 45 L60 50 L55 55" stroke="currentColor" stroke-width="2" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 21</span><h2 class="sec-h">Электрическая цепь. Измерение силы тока и напряжения</h2></div><div id="p21-body"></div></section>
+    <section id="sec-p22" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p22" aria-hidden="true"><svg viewBox="0 0 100 100"><text x="50" y="60" font-family="Unbounded" font-size="36" font-weight="900" fill="currentColor" text-anchor="middle">Ω</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 22</span><h2 class="sec-h">Связь силы тока и напряжения. Закон Ома для участка электрической цепи</h2></div><div id="p22-body"></div></section>
+    <section id="sec-p23" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p23" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M20 50 Q30 20, 40 50 T60 50 T80 50" stroke="currentColor" stroke-width="4" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 23</span><h2 class="sec-h">Единица сопротивления. Расчёт сопротивления</h2></div><div id="p23-body"></div></section>
+    <section id="sec-p24" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p24" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M15 50 L25 50 L30 40 L40 60 L50 40 L60 60 L70 40 L75 50 L85 50" stroke="currentColor" stroke-width="3" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 24</span><h2 class="sec-h">Последовательное соединение проводников. Реостат</h2></div><div id="p24-body"></div></section>
+    <section id="sec-p25" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p25" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M20 30 L80 30 M20 70 L80 70 M50 30 L50 70" stroke="currentColor" stroke-width="3" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 25</span><h2 class="sec-h">Параллельное соединение проводников</h2></div><div id="p25-body"></div></section>
+    <section id="sec-p26" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p26" aria-hidden="true"><svg viewBox="0 0 100 100"><text x="50" y="60" font-family="Unbounded" font-size="32" font-weight="900" fill="currentColor" text-anchor="middle">P</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 26</span><h2 class="sec-h">Работа и мощность электрического тока. Закон Джоуля — Ленца</h2></div><div id="p26-body"></div></section>
+    <section id="sec-p27" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p27" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="28" fill="none" stroke="currentColor" stroke-width="4"/><path d="M28 50 L72 50 M50 28 L50 72" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 27</span><h2 class="sec-h">Использование и экономия электроэнергии. Безопасность</h2></div><div id="p27-body"></div></section>
+    <section id="sec-p28" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p28" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="42" width="60" height="16" fill="currentColor"/><text x="32" y="56" font-family="Unbounded" font-size="14" font-weight="900" fill="#fff" text-anchor="middle">N</text><text x="68" y="56" font-family="Unbounded" font-size="14" font-weight="900" fill="#fff" text-anchor="middle">S</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 28</span><h2 class="sec-h">Постоянные магниты</h2></div><div id="p28-body"></div></section>
+    <section id="sec-p29" class="sec">
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+    <section id="sec-p30" class="sec">
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+    <section id="sec-final2" class="sec"><div class="sec-header"><span class="sec-num">&#9733;</span><h2 class="sec-h">Финал главы</h2></div><div id="final2-body"></div></section>
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-    <div class="p8-hero-eyebrow">Глава 2 · 20 параграфов</div>
-    <h1 class="p8-hero-title">Электромагнитные явления</h1>
-    <div class="p8-hero-sub">Заряд, ток, цепь, магнитное поле. Конструируйте цепи из компонентов, перемещайте заряды, наблюдайте за искрами и полями.</div>
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-      <a href="/textbook/physics-8" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><polyline points="15 18 9 12 15 6"/></svg> К физике 8</a>
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-      <h2>Электромагнитные явления — от заряда до магнита</h2>
-      <p>Заряды притягиваются и отталкиваются, образуют электрическое поле. По проводнику течёт ток, и закон Ома связывает $U$, $I$, $R$. У постоянных магнитов и проводников с током есть магнитное поле.</p>
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-  <div class="p8-sec-wm" id="p8-sec-wm-p14" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="24" fill="none" stroke="currentColor" stroke-width="4"/><path d="M50 26 L50 14 M50 86 L50 74 M26 50 L14 50 M86 50 L74 50" stroke="currentColor" stroke-width="4"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 14</span><h2 class="sec-h">Электризация через влияние</h2></div><div id="p14-body"></div></section>
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-  <div class="p8-sec-wm" id="p8-sec-wm-p15" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="16" fill="currentColor"/><path d="M50 30 L50 18 M50 82 L50 70 M30 50 L18 50 M82 50 L70 50" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 15</span><h2 class="sec-h">Электрический заряд. Элементарный заряд</h2></div><div id="p15-body"></div></section>
-    <section id="sec-p16" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p16" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="6" fill="currentColor"/><ellipse cx="50" cy="50" rx="32" ry="14" fill="none" stroke="currentColor" stroke-width="2.5"/><ellipse cx="50" cy="50" rx="14" ry="32" fill="none" stroke="currentColor" stroke-width="2.5"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 16</span><h2 class="sec-h">Строение атома. Ионы</h2></div><div id="p16-body"></div></section>
-    <section id="sec-p17" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p17" aria-hidden="true"><svg viewBox="0 0 100 100"><line x1="20" y1="50" x2="80" y2="50" stroke="currentColor" stroke-width="3"/><line x1="20" y1="35" x2="80" y2="65" stroke="currentColor" stroke-width="3"/><line x1="20" y1="65" x2="80" y2="35" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 17</span><h2 class="sec-h">Электрическое поле. Электрическое напряжение</h2></div><div id="p17-body"></div></section>
-    <section id="sec-p18" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p18" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M30 50 L70 50" stroke="currentColor" stroke-width="5" fill="none"/><path d="M65 45 L70 50 L65 55" stroke="currentColor" stroke-width="3" fill="none"/><text x="30" y="40" font-family="Inter" font-size="14" font-weight="700" fill="currentColor">U</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 18</span><h2 class="sec-h">Единица электрического напряжения. Расчёт работы в электрическом поле</h2></div><div id="p18-body"></div></section>
-    <section id="sec-p19" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p19" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="40" width="14" height="20" fill="currentColor"/><rect x="38" y="35" width="6" height="30" fill="currentColor"/><line x1="50" y1="50" x2="80" y2="50" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 19</span><h2 class="sec-h">Электрический ток. Источники тока</h2></div><div id="p19-body"></div></section>
-    <section id="sec-p20" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p20" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M20 70 L40 30 L60 70 L80 30" stroke="currentColor" stroke-width="4" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 20</span><h2 class="sec-h">Сила и направление электрического тока</h2></div><div id="p20-body"></div></section>
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-  <div class="p8-sec-wm" id="p8-sec-wm-p21" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="40" width="60" height="20" fill="none" stroke="currentColor" stroke-width="3"/><path d="M30 50 L50 50 M55 45 L60 50 L55 55" stroke="currentColor" stroke-width="2" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 21</span><h2 class="sec-h">Электрическая цепь. Измерение силы тока и напряжения</h2></div><div id="p21-body"></div></section>
-    <section id="sec-p22" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p22" aria-hidden="true"><svg viewBox="0 0 100 100"><text x="50" y="60" font-family="Unbounded" font-size="36" font-weight="900" fill="currentColor" text-anchor="middle">Ω</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 22</span><h2 class="sec-h">Связь силы тока и напряжения. Закон Ома для участка электрической цепи</h2></div><div id="p22-body"></div></section>
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-  <div class="p8-sec-wm" id="p8-sec-wm-p23" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M20 50 Q30 20, 40 50 T60 50 T80 50" stroke="currentColor" stroke-width="4" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 23</span><h2 class="sec-h">Единица сопротивления. Расчёт сопротивления</h2></div><div id="p23-body"></div></section>
-    <section id="sec-p24" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p24" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M15 50 L25 50 L30 40 L40 60 L50 40 L60 60 L70 40 L75 50 L85 50" stroke="currentColor" stroke-width="3" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 24</span><h2 class="sec-h">Последовательное соединение проводников. Реостат</h2></div><div id="p24-body"></div></section>
-    <section id="sec-p25" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p25" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M20 30 L80 30 M20 70 L80 70 M50 30 L50 70" stroke="currentColor" stroke-width="3" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 25</span><h2 class="sec-h">Параллельное соединение проводников</h2></div><div id="p25-body"></div></section>
-    <section id="sec-p26" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p26" aria-hidden="true"><svg viewBox="0 0 100 100"><text x="50" y="60" font-family="Unbounded" font-size="32" font-weight="900" fill="currentColor" text-anchor="middle">P</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 26</span><h2 class="sec-h">Работа и мощность электрического тока. Закон Джоуля — Ленца</h2></div><div id="p26-body"></div></section>
-    <section id="sec-p27" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p27" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="28" fill="none" stroke="currentColor" stroke-width="4"/><path d="M28 50 L72 50 M50 28 L50 72" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 27</span><h2 class="sec-h">Использование и экономия электроэнергии. Безопасность</h2></div><div id="p27-body"></div></section>
-    <section id="sec-p28" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p28" aria-hidden="true"><svg viewBox="0 0 100 100"><rect x="20" y="42" width="60" height="16" fill="currentColor"/><text x="32" y="56" font-family="Unbounded" font-size="14" font-weight="900" fill="#fff" text-anchor="middle">N</text><text x="68" y="56" font-family="Unbounded" font-size="14" font-weight="900" fill="#fff" text-anchor="middle">S</text></svg></div><div class="sec-header"><span class="sec-num">&sect; 28</span><h2 class="sec-h">Постоянные магниты</h2></div><div id="p28-body"></div></section>
-    <section id="sec-p29" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p29" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="6" fill="currentColor"/><ellipse cx="50" cy="50" rx="36" ry="18" fill="none" stroke="currentColor" stroke-width="3"/><path d="M82 38 L86 48 L78 46" stroke="currentColor" stroke-width="3" fill="none"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 29</span><h2 class="sec-h">Магнитное поле</h2></div><div id="p29-body"></div></section>
-    <section id="sec-p30" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p30" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="6" fill="currentColor"/><line x1="50" y1="20" x2="50" y2="80" stroke="currentColor" stroke-width="3"/><line x1="20" y1="50" x2="80" y2="50" stroke="currentColor" stroke-width="3"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 30</span><h2 class="sec-h">Магнитное поле тока</h2></div><div id="p30-body"></div></section>
-    <section id="sec-p31" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p31" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M30 30 Q40 20, 50 30 T70 30 M30 50 Q40 40, 50 50 T70 50 M30 70 Q40 60, 50 70 T70 70" stroke="currentColor" stroke-width="3" fill="none"/><rect x="48" y="20" width="4" height="60" fill="currentColor"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 31</span><h2 class="sec-h">Магнитное поле прямого проводника и катушки с током. Электромагнит</h2></div><div id="p31-body"></div></section>
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+.psel-card.final{background:linear-gradient(135deg,var(--acc-soft),var(--pri-soft))}
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+
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+@media(max-width:980px){.col-side{position:static;max-height:none}}
+
+.xp-card{background:linear-gradient(135deg,var(--acc-soft),var(--pri-soft));border:1.5px solid var(--acc);border-radius:12px;padding:14px;margin-bottom:14px}
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+.xp-nums{font-size:.74rem;color:var(--muted);display:flex;justify-content:space-between}
+
+.sec-nav{display:flex;gap:10px;margin-top:24px;padding-top:20px;border-top:1px solid var(--border);justify-content:space-between;flex-wrap:wrap}
+.foot{text-align:center;padding:30px 16px;color:var(--muted);font-size:.78rem;border-top:1px solid var(--border);margin-top:30px}
+
+.ach-popup{position:fixed;top:80px;right:18px;background:linear-gradient(135deg,var(--pri),var(--acc));color:#fff;padding:12px 18px;border-radius:11px;font-weight:700;font-size:.9rem;box-shadow:0 8px 28px rgba(0,0,0,.32);z-index:1002;display:none;align-items:center;gap:8px;max-width:340px}
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+
+.col-side-backdrop{position:fixed;inset:0;background:rgba(0,0,0,.42);z-index:9990;display:none}
+.col-side-backdrop.show{display:block}
+@media(min-width:981px){#sidebar-btn{display:none}.col-side-backdrop.show{display:none}}
+@media(max-width:980px){
+  .col-side{position:fixed;top:0;right:0;height:100vh;width:300px;max-width:88vw;background:var(--bg);box-shadow:-12px 0 24px rgba(0,0,0,.18);padding:18px 16px;overflow-y:auto;transform:translateX(100%);transition:transform .25s ease;z-index:9991;max-height:none}
+  .col-side.open{transform:none}
+}
+
+.search-modal{position:fixed;inset:0;background:rgba(15,23,42,.55);backdrop-filter:blur(4px);z-index:9993;display:none;align-items:flex-start;justify-content:center;padding-top:14vh}
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+.search-row:hover,.search-row.active{background:var(--sec-acc-soft,var(--pri-soft))}
+.search-row .sr-kind{font-size:.7rem;font-weight:800;color:var(--muted);text-transform:uppercase;letter-spacing:.06em;margin-bottom:2px}
+.search-row .sr-title{font-weight:700;font-size:.92rem;color:var(--text)}
+.search-row .sr-desc{font-size:.8rem;color:var(--muted);margin-top:2px}
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+.search-foot{padding:8px 14px;border-top:1px solid var(--border);font-size:.74rem;color:var(--muted);display:flex;gap:14px}
+.search-foot kbd{padding:2px 6px;background:var(--card);border:1px solid var(--border);border-radius:4px;font-family:'JetBrains Mono',monospace;font-size:.72rem}
+
+.sec{transition:opacity .25s}
+</style>
+</head>
+<body class="p8-theme-spectrum">
+
+<header class="p8-hero">
+  <div class="p8-hero-wm"><svg viewBox="0 0 100 100" aria-hidden="true">
+  <circle cx="50" cy="50" r="22" />
+  <g><line x1="50" y1="8" x2="50" y2="22" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+  <line x1="50" y1="78" x2="50" y2="92" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+  <line x1="8" y1="50" x2="22" y2="50" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+  <line x1="78" y1="50" x2="92" y2="50" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+  <line x1="20" y1="20" x2="30" y2="30" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+  <line x1="70" y1="70" x2="80" y2="80" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+  <line x1="80" y1="20" x2="70" y2="30" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+  <line x1="30" y1="70" x2="20" y2="80" stroke="currentColor" stroke-width="4" stroke-linecap="round"/></g>
+</svg></div>
+  <div class="p8-hero-meter" id="p8-meter-ch3"><span id="p8-meter-val">λ=550</span> нм</div>
+  <div class="p8-hero-inner">
+    <div class="p8-hero-eyebrow">Глава 3 · 9 параграфов</div>
+    <h1 class="p8-hero-title">Световые явления</h1>
+    <div class="p8-hero-sub">Лучи, тени, отражение, преломление, линзы, дисперсия, глаз. Перетаскивайте источники света и зеркала, наблюдайте за лучами и спектром.</div>
+    <div class="hdr-side" style="margin-top:18px;display:flex;gap:8px;flex-wrap:wrap;position:relative;z-index:1">
+      <a href="/textbook/physics-8" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><polyline points="15 18 9 12 15 6"/></svg> К физике 8</a>
+      <button id="search-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><circle cx="11" cy="11" r="7"/><path d="m21 21-4-4"/></svg> Поиск</button>
+      <button id="sidebar-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><line x1="4" y1="6" x2="20" y2="6"/><line x1="4" y1="12" x2="20" y2="12"/><line x1="4" y1="18" x2="14" y2="18"/></svg> Шпаргалка</button>
+      <button id="theme-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><path d="M21 12.8A9 9 0 1 1 11.2 3a7 7 0 0 0 9.8 9.8z"/></svg><span id="theme-lab">Тёмная</span></button>
+    </div>
+  </div>
+</header>
+
+<main class="main">
+  <div class="col-main">
+
+    <section class="hero">
+      <h2>Световые явления — геометрическая оптика</h2>
+      <p>Свет распространяется прямолинейно со скоростью $c = 3 \cdot 10^8$ м/с. Закон отражения и закон преломления (Снеллиуса) объясняют поведение пучков света. Линзы строят изображения; глаз — это оптическая система.</p>
+      <div class="hero-row">
+        <button class="btn-primary" onclick="goTo('p32')"><svg class="ic" viewBox="0 0 24 24"><polygon points="6 4 20 12 6 20 6 4" fill="currentColor" stroke="none"/></svg> Начать § 32</button>
+        <div class="hero-progress">
+          <span class="hp-label">Прогресс по главе</span>
+          <div class="hp-bar"><div id="hero-hp-fill" class="hp-fill"></div></div>
+          <span id="hero-hp-text" class="hp-text">0%</span>
+        </div>
+        <div id="hero-xp-badge" class="hero-xp-badge" data-gamified></div>
+      </div>
+    </section>
+
+    <section class="psel">
+      <div class="psel-title">Параграфы главы</div>
+      <div id="psel-grid" class="psel-grid"></div>
+    </section>
+
+    <section id="sec-p32" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p32" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="14" fill="currentColor"/><g stroke="currentColor" stroke-width="4" stroke-linecap="round"><line x1="50" y1="14" x2="50" y2="26"/><line x1="50" y1="74" x2="50" y2="86"/><line x1="14" y1="50" x2="26" y2="50"/><line x1="74" y1="50" x2="86" y2="50"/></g></svg></div><div class="sec-header"><span class="sec-num">&sect; 32</span><h2 class="sec-h">Источники света</h2></div><div id="p32-body"></div></section>
+    <section id="sec-p33" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p33" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="32" cy="40" r="10" fill="currentColor"/><rect x="50" y="34" width="14" height="40" fill="currentColor"/><polygon points="68,40 92,30 92,80 68,70" fill="currentColor" opacity="0.5"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 33</span><h2 class="sec-h">Скорость света. Прямолинейное распространение света</h2></div><div id="p33-body"></div></section>
+    <section id="sec-p34" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p34" aria-hidden="true"><svg viewBox="0 0 100 100"><line x1="20" y1="20" x2="50" y2="50" stroke="currentColor" stroke-width="5"/><line x1="50" y1="50" x2="80" y2="20" stroke="currentColor" stroke-width="5"/><line x1="50" y1="50" x2="50" y2="90" stroke="currentColor" stroke-width="2" stroke-dasharray="4 4"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 34</span><h2 class="sec-h">Отражение света</h2></div><div id="p34-body"></div></section>
+    <section id="sec-p35" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p35" aria-hidden="true"><svg viewBox="0 0 100 100"><line x1="30" y1="20" x2="30" y2="80" stroke="currentColor" stroke-width="4"/><g stroke="currentColor" stroke-width="1.5"><line x1="30" y1="30" x2="22" y2="34"/><line x1="30" y1="45" x2="22" y2="49"/><line x1="30" y1="60" x2="22" y2="64"/><line x1="30" y1="75" x2="22" y2="79"/></g><circle cx="60" cy="50" r="6" fill="currentColor"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 35</span><h2 class="sec-h">Зеркала. Изображение в плоском зеркале</h2></div><div id="p35-body"></div></section>
+    <section id="sec-p36" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p36" aria-hidden="true"><svg viewBox="0 0 100 100"><path d="M30 20 Q 20 50, 30 80" stroke="currentColor" stroke-width="5" fill="none"/><line x1="48" y1="50" x2="70" y2="50" stroke="currentColor" stroke-width="2" stroke-dasharray="3 3"/><circle cx="70" cy="50" r="3" fill="currentColor"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 36</span><h2 class="sec-h">Преломление света</h2></div><div id="p36-body"></div></section>
+    <section id="sec-p37" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p37" aria-hidden="true"><svg viewBox="0 0 100 100"><line x1="20" y1="20" x2="50" y2="50" stroke="currentColor" stroke-width="5"/><line x1="50" y1="50" x2="80" y2="80" stroke="currentColor" stroke-width="5" stroke-dasharray="0"/><line x1="0" y1="50" x2="100" y2="50" stroke="currentColor" stroke-width="2"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 37</span><h2 class="sec-h">Линзы. Оптическая сила линзы</h2></div><div id="p37-body"></div></section>
+    <section id="sec-p38" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p38" aria-hidden="true"><svg viewBox="0 0 100 100"><ellipse cx="50" cy="50" rx="10" ry="36" fill="currentColor" opacity="0.4"/><line x1="0" y1="50" x2="100" y2="50" stroke="currentColor" stroke-width="2"/><circle cx="25" cy="50" r="2" fill="currentColor"/><circle cx="75" cy="50" r="2" fill="currentColor"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 38</span><h2 class="sec-h">Построение изображений в тонких линзах</h2></div><div id="p38-body"></div></section>
+    <section id="sec-p39" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p39" aria-hidden="true"><svg viewBox="0 0 100 100"><polygon points="40,20 80,50 40,80" stroke="currentColor" stroke-width="4" fill="none"/><line x1="20" y1="50" x2="40" y2="50" stroke="currentColor" stroke-width="3"/><g stroke-width="2.5" fill="none"><line x1="60" y1="40" x2="90" y2="30" stroke="#dc2626"/><line x1="60" y1="50" x2="90" y2="50" stroke="#16a34a"/><line x1="60" y1="60" x2="90" y2="70" stroke="#2563eb"/></g></svg></div><div class="sec-header"><span class="sec-num">&sect; 39</span><h2 class="sec-h">Глаз как оптическая система</h2></div><div id="p39-body"></div></section>
+    <section id="sec-p40" class="sec">
+  <div class="p8-sec-wm" id="p8-sec-wm-p40" aria-hidden="true"><svg viewBox="0 0 100 100"><ellipse cx="50" cy="50" rx="36" ry="22" fill="none" stroke="currentColor" stroke-width="3"/><circle cx="50" cy="50" r="12" fill="currentColor"/><circle cx="50" cy="50" r="5" fill="#fff"/></svg></div><div class="sec-header"><span class="sec-num">&sect; 40</span><h2 class="sec-h">Дефекты зрения. Очки</h2></div><div id="p40-body"></div></section>
+    <section id="sec-final3" class="sec"><div class="sec-header"><span class="sec-num">&#9733;</span><h2 class="sec-h">Финал главы</h2></div><div id="final3-body"></div></section>
+
+  </div>
+  <aside class="col-side" id="col-side"><div id="sidebar-content"></div></aside>
+  <div class="col-side-backdrop" id="col-side-backdrop"></div>
+</main>
+
+<footer class="foot">Интерактивный учебник «Физика 8» · Глава 3 · «Световые явления» · LearnSpace</footer>
+
+<div id="ach-popup" class="ach-popup"><svg class="ic" viewBox="0 0 24 24" style="width:22px;height:22px"><polygon points="12,2 22,20 2,20"/></svg><span id="ach-text">Достижение!</span></div>
+<div id="search-modal" class="search-modal" role="dialog">
+  <div class="search-box">
+    <input type="text" id="search-input" class="search-input" placeholder="Поиск…" autocomplete="off">
+    <div id="search-results" class="search-results"></div>
+    <div class="search-foot"><span><kbd>↑↓</kbd> навигация</span><span><kbd>Enter</kbd> открыть</span><span><kbd>Esc</kbd> закрыть</span></div>
+  </div>
+</div>
+
+<script>
+'use strict';
 function _initP40_iv6(){
   const sb = document.getElementById('p40-iv6-sandbox');
   if (!sb || !window.P8Helpers) return;
@@ -428,262 +683,6 @@ function _initp32_iv5(){
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-<head>
-<meta charset="UTF-8">
-<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate">
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-  <div class="p8-hero-meter" id="p8-meter-ch3"><span id="p8-meter-val">λ=550</span> нм</div>
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-    <div class="p8-hero-eyebrow">Глава 3 · 9 параграфов</div>
-    <h1 class="p8-hero-title">Световые явления</h1>
-    <div class="p8-hero-sub">Лучи, тени, отражение, преломление, линзы, дисперсия, глаз. Перетаскивайте источники света и зеркала, наблюдайте за лучами и спектром.</div>
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-      <a href="/textbook/physics-8" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><polyline points="15 18 9 12 15 6"/></svg> К физике 8</a>
-      <button id="search-btn" class="hdr-btn"><svg class="ic" viewBox="0 0 24 24"><circle cx="11" cy="11" r="7"/><path d="m21 21-4-4"/></svg> Поиск</button>
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-      <h2>Световые явления — геометрическая оптика</h2>
-      <p>Свет распространяется прямолинейно со скоростью $c = 3 \cdot 10^8$ м/с. Закон отражения и закон преломления (Снеллиуса) объясняют поведение пучков света. Линзы строят изображения; глаз — это оптическая система.</p>
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-        <button class="btn-primary" onclick="goTo('p32')"><svg class="ic" viewBox="0 0 24 24"><polygon points="6 4 20 12 6 20 6 4" fill="currentColor" stroke="none"/></svg> Начать § 32</button>
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-          <span id="hero-hp-text" class="hp-text">0%</span>
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-    <section class="psel">
-      <div class="psel-title">Параграфы главы</div>
-      <div id="psel-grid" class="psel-grid"></div>
-    </section>
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-    <section id="sec-p32" class="sec">
-  <div class="p8-sec-wm" id="p8-sec-wm-p32" aria-hidden="true"><svg viewBox="0 0 100 100"><circle cx="50" cy="50" r="14" fill="currentColor"/><g stroke="currentColor" stroke-width="4" stroke-linecap="round"><line x1="50" y1="14" x2="50" y2="26"/><line x1="50" y1="74" x2="50" y2="86"/><line x1="14" y1="50" x2="26" y2="50"/><line x1="74" y1="50" x2="86" y2="50"/></g></svg></div><div class="sec-header"><span class="sec-num">&sect; 32</span><h2 class="sec-h">Источники света</h2></div><div id="p32-body"></div></section>
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