/* ══════════════════════════════════════════════════════════════
   বই সমূহ — style.css
   root index.html-এর ডিজাইন সিস্টেম অনুসরণ করে (--bg/--surface/
   --border/--text-primary ইত্যাদি নাম হুবহু মিলিয়ে রাখা হয়েছে
   যাতে ভবিষ্যতে ভিজুয়াল ভাষা এক থাকে)।
   ══════════════════════════════════════════════════════════════ */

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

:root {
  --bg: #f5f1eb;
  --surface: #ffffff;
  --border: #e0d8cc;
  --text-primary: #1a1814;
  --text-secondary: #6b6358;
  --accent-books: #b45309;
  --accent-books-light: #fef3e2;
  --shadow: 0 2px 16px rgba(0,0,0,0.08);
  --shadow-hover: 0 8px 32px rgba(0,0,0,0.14);
  --radius: 16px;
}
[data-theme="dark"] {
  --bg: #1a1814;
  --surface: #24211c;
  --border: #3a3530;
  --text-primary: #f0ece4;
  --text-secondary: #a89e92;
  --accent-books: #f0a24d;
  --accent-books-light: #3a2a14;
  --shadow: 0 2px 16px rgba(0,0,0,0.4);
  --shadow-hover: 0 8px 32px rgba(0,0,0,0.5);
}

body {
  font-family: 'Noto Serif Bengali', serif;
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100dvh;
  padding: 24px 16px 60px;
  transition: background 0.3s, color 0.3s;
}

.page-wrap { width: 100%; max-width: 640px; margin: 0 auto; }

header.top {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
}
.back-btn {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 50%;
  width: 40px; height: 40px;
  display: flex; align-items: center; justify-content: center;
  text-decoration: none; color: var(--text-primary);
  font-size: 1.2rem; flex-shrink: 0;
  box-shadow: var(--shadow);
}
h1 { font-size: 1.5rem; font-weight: 700; flex: 1; }
.theme-btn {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 50%;
  width: 40px; height: 40px;
  font-size: 1.1rem; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow); flex-shrink: 0;
}

/* ── শেলফ পেজ ── */
.book-section { margin-bottom: 32px; }
.book-section-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 4px;
  display: flex; align-items: center; gap: 8px;
}
.book-section-desc {
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-bottom: 14px;
}
.subject-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}
.subject-card {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  text-decoration: none;
  color: var(--text-primary);
  box-shadow: var(--shadow);
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
  display: flex; flex-direction: column; gap: 8px;
}
.subject-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
  border-color: var(--accent-books);
}
.subject-card:active { transform: translateY(0px); }
.subject-icon {
  width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--accent-books-light);
  color: var(--accent-books);
  display: flex; align-items: center; justify-content: center;
}
.subject-icon svg { width: 22px; height: 22px; }
.subject-label { font-weight: 700; font-size: 0.98rem; }
.subject-marks { color: var(--text-secondary); font-size: 0.78rem; }

/* ── বিষয়-পাতা (book.html) ── */
.subject-page-header {
  display: flex; align-items: center; gap: 14px;
  margin-bottom: 20px;
}
.subject-page-icon {
  width: 56px; height: 56px; flex-shrink: 0;
  border-radius: 14px;
  background: var(--accent-books-light);
  color: var(--accent-books);
  display: flex; align-items: center; justify-content: center;
}
.subject-page-icon svg { width: 30px; height: 30px; }
.subject-page-title { font-size: 1.4rem; font-weight: 700; }
.subject-page-book { color: var(--text-secondary); font-size: 0.85rem; }

.coming-soon {
  background: var(--surface);
  border: 1.5px dashed var(--border);
  border-radius: var(--radius);
  padding: 40px 24px;
  text-align: center;
  color: var(--text-secondary);
}
.coming-soon .emoji { font-size: 2.2rem; margin-bottom: 10px; }
.coming-soon .msg { font-size: 1rem; line-height: 1.6; }

footer {
  margin-top: 36px;
  color: var(--text-secondary);
  font-size: 0.8rem;
  text-align: center;
}

@media (max-width: 420px) {
  .subject-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
  .subject-card { padding: 14px; }
}