/* ============================================================
   PROFESSIONAL TEXTBOOK STYLESHEET
   NEW ADDITIONAL MATHEMATICS FOR CAMBRIDGE O LEVEL (4037)
   ORIGINAL ONLINE VERSION - DARK GREEN & GOLD THEME
   ============================================================ */

/* === RESET & BASE === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Times New Roman', 'Georgia', serif;
    font-size: 16px;
    line-height: 1.8;
    color: #1e1e1e;
    background: #f5f3f0;
    padding: 30px 20px;
}

.container {
    max-width: 950px;
    margin: 0 auto;
    background: #ffffff;
    padding: 50px 60px 40px;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.08);
    border-radius: 6px;
}

/* === HEADINGS === */
h1 {
    font-size: 32px;
    color: #1a3b5d;
    border-bottom: 3px solid #d4af37;
    padding-bottom: 12px;
    margin-bottom: 30px;
    text-align: center;
    font-weight: bold;
    letter-spacing: 0.5px;
}

h2 {
    font-size: 24px;
    color: #1a3b5d;
    border-bottom: 2px solid #d4af37;
    padding-bottom: 8px;
    margin-top: 35px;
    margin-bottom: 18px;
    font-weight: bold;
}

h3 {
    font-size: 19px;
    color: #1a3b5d;
    margin-top: 25px;
    margin-bottom: 12px;
    font-weight: bold;
}

h4 {
    font-size: 17px;
    color: #1a3b5d;
    margin-top: 18px;
    margin-bottom: 10px;
    font-weight: bold;
}

/* === PARAGRAPHS & LISTS === */
p {
    margin-bottom: 14px;
    text-align: justify;
}

ul, ol {
    margin: 10px 0 16px 25px;
}

li {
    margin-bottom: 4px;
}

/* === LINKS === */
a {
    color: #1a3b5d;
    text-decoration: none;
    border-bottom: 1px dotted #d4af37;
    transition: color 0.2s ease, border-color 0.2s ease;
}

a:hover {
    color: #d4af37;
    border-bottom-color: #1a3b5d;
}

/* === NAVIGATION === */
.top-nav, .bottom-nav {
    background: #1a3b5d;
    padding: 14px 20px;
    border-radius: 4px;
    margin: 20px 0 30px;
    text-align: center;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 6px;
}

.top-nav a, .bottom-nav a {
    color: #f5f3f0;
    border-bottom: none;
    padding: 6px 16px;
    border-radius: 3px;
    font-size: 15px;
    transition: background 0.2s ease, color 0.2s ease;
}

.top-nav a:hover, .bottom-nav a:hover {
    background: #d4af37;
    color: #1a3b5d;
}

.top-nav .nav-title {
    color: #d4af37;
    font-weight: bold;
    padding: 6px 16px;
    font-size: 15px;
    letter-spacing: 1px;
}

/* === TABLES === */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 18px 0 22px;
    font-size: 15px;
}

th, td {
    border: 1px solid #d0d0d0;
    padding: 10px 16px;
    text-align: left;
    vertical-align: top;
}

th {
    background: #e8edf3;
    color: #1a3b5d;
    font-weight: bold;
}

tr:nth-child(even) {
    background: #f9f9f9;
}

/* === BOXES === */
.summary-box {
    background: #eef4fb;
    border-left: 6px solid #1a3b5d;
    padding: 16px 22px;
    margin: 18px 0 22px;
    border-radius: 0 4px 4px 0;
    font-weight: bold;
}

.summary-box ul, .summary-box ol {
    font-weight: normal;
    margin-left: 20px;
}

.example-box {
    background: #f0f7f0;
    border-left: 6px solid #2e7d32;
    padding: 16px 22px;
    margin: 18px 0 22px;
    border-radius: 0 4px 4px 0;
}

.solution-box {
    background: #fff8e7;
    border-left: 6px solid #b8860b;
    padding: 16px 22px;
    margin: 18px 0 22px;
    border-radius: 0 4px 4px 0;
}

.mauritian-box {
    background: #eaf3e8;
    border-left: 6px solid #1a6b30;
    padding: 16px 22px;
    margin: 18px 0 22px;
    border-radius: 0 4px 4px 0;
}

.note-box {
    background: #f0f0f0;
    border-left: 6px solid #888;
    padding: 16px 22px;
    margin: 18px 0 22px;
    border-radius: 0 4px 4px 0;
    font-style: italic;
}

.formula-box {
    background: #f7f9fc;
    padding: 14px 20px;
    border: 1px solid #d0d8e0;
    border-radius: 4px;
    margin: 14px 0 18px;
    font-family: 'Courier New', monospace;
    font-size: 17px;
    text-align: center;
    color: #1a3b5d;
}

/* === CHAPTER SUMMARY TABLE === */
.chapter-summary {
    background: #f7f9fc;
    border: 1px solid #d0d8e0;
    border-radius: 4px;
    padding: 12px 16px;
    margin: 18px 0 24px;
}

.chapter-summary table {
    margin: 0;
}

.chapter-summary th {
    background: #1a3b5d;
    color: #ffffff;
}

/* === EXERCISES === */
.exercise-section {
    margin-top: 35px;
    padding-top: 25px;
    border-top: 3px solid #d4af37;
}

.exercise-section h3 {
    color: #1a3b5d;
    font-size: 18px;
    border-bottom: 1px solid #d0d0d0;
    padding-bottom: 5px;
    margin-top: 20px;
}

.exercise-section ol {
    padding-left: 28px;
    margin-bottom: 18px;
}

.exercise-section ol li {
    margin-bottom: 8px;
}

/* === TITLE PAGE - DARK GREEN === */
.title-page {
    text-align: center;
    padding: 50px 30px 40px;
    background: #005028;
    color: #ffffff;
    border-radius: 6px;
    margin-bottom: 35px;
}

.title-page h1 {
    font-size: 42px;
    color: #ffffff;
    border-bottom: none;
    margin-bottom: 5px;
    letter-spacing: 2px;
}

.title-page h1 .gold {
    color: #d4af37;
}

.title-page .subtitle {
    font-size: 22px;
    color: #a8d0e6;
    margin-top: 5px;
}

.title-page .edition {
    font-size: 16px;
    color: #a8d0e6;
    margin-top: 5px;
}

.title-page .description {
    font-size: 16px;
    color: #e0e8f0;
    margin-top: 12px;
}

.title-page .author {
    font-size: 20px;
    color: #d4af37;
    margin-top: 25px;
    font-weight: bold;
}

.title-page .cambridge {
    font-size: 13px;
    color: #a8d0e6;
    margin-top: 15px;
}

/* === PREFACE === */
.preface-box {
    background: #eef4fb;
    padding: 24px 28px;
    border-radius: 6px;
    margin: 20px 0 30px;
}

.preface-box h2 {
    border-bottom: none;
    margin-top: 0;
    color: #1a3b5d;
}

.preface-box ul {
    margin-top: 8px;
}

/* === TABLE OF CONTENTS === */
.toc-list {
    list-style: none;
    padding: 0;
    margin: 20px 0;
}

.toc-list li {
    padding: 12px 18px;
    border-bottom: 1px solid #e8e8e8;
    font-size: 17px;
    transition: background 0.2s ease;
}

.toc-list li:hover {
    background: #f5f3f0;
}

.toc-list li a {
    display: block;
    color: #1a3b5d;
    text-decoration: none;
    border-bottom: none;
}

.toc-list li a:hover {
    color: #d4af37;
    padding-left: 6px;
}

.toc-chapter {
    font-weight: bold;
    color: #1a3b5d;
}

/* === FOOTER === */
.footer {
    text-align: center;
    font-size: 14px;
    color: #888;
    border-top: 1px solid #e0e0e0;
    padding-top: 22px;
    margin-top: 35px;
}

/* === RESPONSIVE === */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    .container {
        padding: 20px 24px;
    }
    h1 {
        font-size: 26px;
    }
    h2 {
        font-size: 20px;
    }
    h3 {
        font-size: 17px;
    }
    table, td, th {
        font-size: 14px;
        padding: 8px 10px;
    }
    .top-nav a, .bottom-nav a {
        font-size: 13px;
        padding: 4px 10px;
    }
    .formula-box {
        font-size: 15px;
        padding: 10px 14px;
    }
    .title-page h1 {
        font-size: 30px;
    }
    .title-page .subtitle {
        font-size: 18px;
    }
    .top-nav {
        flex-wrap: wrap;
        gap: 4px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 14px 16px;
    }
    h1 {
        font-size: 22px;
    }
    h2 {
        font-size: 18px;
    }
    .top-nav a, .bottom-nav a {
        font-size: 12px;
        padding: 3px 8px;
    }
    .title-page {
        padding: 30px 16px;
    }
    .title-page h1 {
        font-size: 24px;
    }
}