/* ============================================
   BioWaleSir — Main Stylesheet
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,700;0,900;1,700&family=Lora:wght@400;500;600&family=DM+Sans:wght@300;400;500;600&display=swap');

:root {
  --green-900: #0a1f0f;
  --green-800: #0d2b14;
  --green-700: #1a4228;
  --green-600: #1e5c35;
  --green-500: #2e7d4f;
  --green-400: #3da467;
  --green-300: #6dbe8e;
  --green-100: #c8f0d8;
  --cream: #f8f3eb;
  --cream-dark: #ede8df;
  --gold: #c9922a;
  --gold-light: #e8c97a;
  --white: #ffffff;
  --text-dark: #1a1a1a;
  --text-mid: #444;
  --text-light: #777;
  --shadow: 0 4px 24px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.12);
  --radius: 12px;
  --nav-height: 68px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'DM Sans', sans-serif;
  background: var(--cream);
  color: var(--text-dark);
  line-height: 1.6;
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

/* ===== NAVBAR ===== */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-height);
  background: var(--green-900);
  z-index: 1000;
  display: flex;
  align-items: center;
  padding: 0 40px;
  gap: 0;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}

.nav-logo {
  font-family: 'Playfair Display', serif;
  font-size: 20px;
  color: var(--white);
  display: flex;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
  flex-shrink: 0;
}
.nav-logo .leaf { font-size: 22px; }
.nav-logo span { color: var(--green-300); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: auto;
  list-style: none;
}

.nav-links li a,
.nav-links li button {
  display: block;
  padding: 8px 14px;
  font-size: 13.5px;
  font-weight: 500;
  color: rgba(255,255,255,0.75);
  border-radius: 8px;
  transition: all 0.2s;
  background: none;
  border: none;
  cursor: pointer;
  font-family: 'DM Sans', sans-serif;
  white-space: nowrap;
}
.nav-links li a:hover,
.nav-links li button:hover { color: #fff; background: rgba(255,255,255,0.08); }
.nav-links li a.active { color: var(--green-300); background: rgba(61,164,103,0.15); }

/* Class nav items styled special */
.nav-class a {
  color: var(--green-100) !important;
  border: 1px solid rgba(109,190,142,0.25) !important;
}
.nav-class a:hover {
  background: rgba(61,164,103,0.2) !important;
  border-color: var(--green-300) !important;
  color: #fff !important;
}

/* More dropdown */
.nav-more { position: relative; }
.nav-more-btn {
  display: flex; align-items: center; gap: 6px;
}
.nav-more-btn::after { content: '▾'; font-size: 10px; }
.nav-dropdown {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--green-800);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 10px;
  padding: 8px;
  min-width: 160px;
  box-shadow: var(--shadow-lg);
}
.nav-more:hover .nav-dropdown { display: block; }
.nav-dropdown a {
  display: block;
  padding: 9px 14px;
  font-size: 13px;
  color: rgba(255,255,255,0.8) !important;
  border-radius: 6px;
  transition: all 0.15s;
}
.nav-dropdown a:hover { background: rgba(255,255,255,0.08); color: #fff !important; }

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  margin-left: auto;
  background: none;
  border: none;
  padding: 6px;
}
.hamburger span {
  display: block;
  width: 24px; height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: all 0.3s;
}
.hamburger.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* Mobile nav */
.mobile-nav {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0; right: 0;
  background: var(--green-900);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  padding: 16px 24px 24px;
  z-index: 999;
  flex-direction: column;
  gap: 4px;
}
.mobile-nav.open { display: flex; }
.mobile-nav a {
  padding: 11px 14px;
  font-size: 15px;
  font-weight: 500;
  color: rgba(255,255,255,0.8);
  border-radius: 8px;
  transition: all 0.15s;
}
.mobile-nav a:hover { background: rgba(255,255,255,0.08); color: #fff; }
.mobile-nav .mobile-divider {
  height: 1px;
  background: rgba(255,255,255,0.08);
  margin: 8px 0;
}

/* ===== PAGE OFFSET ===== */
.page-offset { padding-top: var(--nav-height); }

/* ===== HERO ===== */
.hero {
  min-height: 92vh;
  background: linear-gradient(160deg, var(--green-900) 0%, var(--green-700) 60%, var(--green-600) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  padding: 80px 40px 60px;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: 
    radial-gradient(ellipse at 20% 50%, rgba(61,164,103,0.15) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 20%, rgba(46,125,79,0.2) 0%, transparent 50%);
}

.hero-bg-text {
  position: absolute;
  font-family: 'Playfair Display', serif;
  font-size: clamp(80px, 18vw, 200px);
  font-weight: 900;
  color: rgba(255,255,255,0.025);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  white-space: nowrap;
  pointer-events: none;
  letter-spacing: -4px;
}

.hero-content {
  position: relative;
  text-align: center;
  max-width: 800px;
}

.hero-tag {
  display: inline-block;
  background: rgba(109,190,142,0.2);
  border: 1px solid rgba(109,190,142,0.4);
  color: var(--green-100);
  font-size: 11px;
  letter-spacing: 3px;
  text-transform: uppercase;
  padding: 6px 18px;
  border-radius: 20px;
  margin-bottom: 24px;
  font-weight: 600;
  animation: fadeUp 0.6s ease both;
}

.hero h1 {
  font-family: 'Playfair Display', serif;
  font-size: clamp(36px, 7vw, 72px);
  color: var(--white);
  line-height: 1.1;
  margin-bottom: 8px;
  animation: fadeUp 0.6s 0.1s ease both;
}
.hero h1 .highlight { color: var(--green-300); font-style: italic; }

.hero-site-name {
  font-size: clamp(13px, 2vw, 16px);
  color: var(--green-100);
  letter-spacing: 1px;
  margin-bottom: 24px;
  font-weight: 500;
  opacity: 0.85;
  animation: fadeUp 0.6s 0.15s ease both;
}

.hero-quote {
  font-family: 'Lora', serif;
  font-size: clamp(16px, 2.5vw, 22px);
  color: rgba(255,255,255,0.85);
  font-style: italic;
  line-height: 1.5;
  margin-bottom: 40px;
  animation: fadeUp 0.6s 0.2s ease both;
}
.hero-quote::before { content: '" '; color: var(--green-300); }
.hero-quote::after { content: ' "'; color: var(--green-300); }

.hero-btns {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeUp 0.6s 0.3s ease both;
}

.btn-primary {
  background: var(--green-400);
  color: #fff;
  padding: 14px 32px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 15px;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.btn-primary:hover { background: var(--green-300); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(61,164,103,0.4); }

.btn-outline {
  border: 1.5px solid rgba(255,255,255,0.3);
  color: #fff;
  padding: 14px 32px;
  border-radius: 50px;
  font-weight: 500;
  font-size: 15px;
  transition: all 0.2s;
}
.btn-outline:hover { border-color: #fff; background: rgba(255,255,255,0.08); }

.hero-stats {
  display: flex;
  gap: 40px;
  justify-content: center;
  margin-top: 60px;
  animation: fadeUp 0.6s 0.4s ease both;
  flex-wrap: wrap;
}
.hero-stat { text-align: center; }
.hero-stat .num {
  font-family: 'Playfair Display', serif;
  font-size: 32px;
  font-weight: 900;
  color: var(--green-300);
}
.hero-stat .lbl {
  font-size: 11px;
  color: rgba(255,255,255,0.5);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-top: 2px;
}

/* ===== CLASS CARDS SECTION ===== */
.section { padding: 80px 40px; }
.section-alt { background: var(--cream-dark); }

.section-label {
  font-size: 11px;
  letter-spacing: 4px;
  text-transform: uppercase;
  color: var(--green-500);
  font-weight: 600;
  margin-bottom: 10px;
}
.section-title {
  font-family: 'Playfair Display', serif;
  font-size: clamp(28px, 5vw, 42px);
  color: var(--text-dark);
  line-height: 1.2;
  margin-bottom: 12px;
}
.section-desc {
  color: var(--text-light);
  font-size: 15px;
  max-width: 560px;
  margin-bottom: 48px;
}

.class-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  max-width: 1100px;
  margin: 0 auto;
}

.class-card {
  background: var(--white);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: all 0.25s;
  display: flex;
  flex-direction: column;
}
.class-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }

.class-card-top {
  padding: 32px 28px 24px;
  background: var(--green-800);
  position: relative;
  overflow: hidden;
}
.class-card-top::after {
  content: attr(data-class);
  position: absolute;
  right: -10px; bottom: -20px;
  font-family: 'Playfair Display', serif;
  font-size: 80px;
  font-weight: 900;
  color: rgba(255,255,255,0.05);
}
.class-card-label {
  font-size: 10px;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--green-300);
  font-weight: 600;
  margin-bottom: 6px;
}
.class-card-title {
  font-family: 'Playfair Display', serif;
  font-size: 26px;
  color: #fff;
}

.class-card-body {
  padding: 20px 28px 28px;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.class-card-body p {
  font-size: 13.5px;
  color: var(--text-light);
  margin-bottom: 16px;
  flex: 1;
}
.class-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 20px;
}
.ctag {
  font-size: 11px;
  background: var(--cream);
  color: var(--green-600);
  border: 1px solid var(--cream-dark);
  padding: 3px 10px;
  border-radius: 20px;
  font-weight: 500;
}
.class-card-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--green-700);
  color: #fff;
  padding: 11px 20px;
  border-radius: 8px;
  font-size: 13.5px;
  font-weight: 600;
  transition: all 0.2s;
}
.class-card-link:hover { background: var(--green-500); }

/* ===== ABOUT SECTION ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  max-width: 1100px;
  margin: 0 auto;
}

.about-image-wrap {
  position: relative;
}
.about-image-box {
  background: var(--green-800);
  border-radius: 20px;
  height: 400px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 80px;
  position: relative;
  overflow: hidden;
}
.about-image-box::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--green-900), var(--green-600));
}
.about-image-emoji { position: relative; z-index: 1; }
.about-badge {
  position: absolute;
  bottom: -16px; right: -16px;
  background: var(--gold);
  color: #fff;
  padding: 14px 20px;
  border-radius: 12px;
  font-family: 'Playfair Display', serif;
  font-size: 20px;
  font-weight: 700;
  text-align: center;
  box-shadow: var(--shadow);
}
.about-badge span { display: block; font-size: 11px; font-family: 'DM Sans', sans-serif; opacity: 0.85; font-weight: 500; }

.about-text { padding: 20px 0; }
.about-text .section-desc { margin-bottom: 28px; max-width: 100%; }

.about-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}
.about-tab {
  padding: 8px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  background: var(--cream-dark);
  color: var(--text-mid);
  border: none;
  transition: all 0.2s;
  font-family: 'DM Sans', sans-serif;
}
.about-tab.active {
  background: var(--green-700);
  color: #fff;
}

.about-panel { display: none; }
.about-panel.active { display: block; }
.about-panel p {
  font-size: 14.5px;
  color: var(--text-mid);
  line-height: 1.7;
}

/* ===== FEATURES ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
  max-width: 1100px;
  margin: 0 auto;
}
.feature-card {
  background: var(--white);
  border-radius: 14px;
  padding: 28px 24px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: transform 0.2s;
}
.feature-card:hover { transform: translateY(-4px); }
.feature-icon { font-size: 36px; margin-bottom: 14px; }
.feature-title {
  font-family: 'Playfair Display', serif;
  font-size: 17px;
  margin-bottom: 8px;
  color: var(--text-dark);
}
.feature-desc { font-size: 13px; color: var(--text-light); line-height: 1.5; }

/* ===== CONTACT ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  max-width: 900px;
  margin: 0 auto;
}
.contact-info h3 {
  font-family: 'Playfair Display', serif;
  font-size: 24px;
  margin-bottom: 16px;
}
.contact-info p { font-size: 14.5px; color: var(--text-mid); line-height: 1.7; margin-bottom: 24px; }
.contact-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--cream-dark);
  font-size: 14px;
  color: var(--text-mid);
}
.contact-item span:first-child { font-size: 20px; }

.contact-form { display: flex; flex-direction: column; gap: 14px; }
.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-group label { font-size: 13px; font-weight: 600; color: var(--text-mid); }
.form-group input,
.form-group textarea,
.form-group select {
  padding: 11px 14px;
  border: 1.5px solid var(--cream-dark);
  border-radius: 8px;
  font-size: 14px;
  font-family: 'DM Sans', sans-serif;
  background: var(--white);
  color: var(--text-dark);
  transition: border-color 0.2s;
  outline: none;
}
.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus { border-color: var(--green-400); }
.form-group textarea { resize: vertical; min-height: 100px; }
.btn-submit {
  background: var(--green-700);
  color: #fff;
  padding: 13px 28px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  font-family: 'DM Sans', sans-serif;
  transition: all 0.2s;
  align-self: flex-start;
}
.btn-submit:hover { background: var(--green-500); }

/* ===== FOOTER ===== */
.footer {
  background: var(--green-900);
  padding: 60px 40px 30px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  max-width: 1100px;
  margin: 0 auto 48px;
}
.footer-brand .logo {
  font-family: 'Playfair Display', serif;
  font-size: 22px;
  color: #fff;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.footer-brand .logo span { color: var(--green-300); }
.footer-brand p {
  font-size: 13.5px;
  color: rgba(255,255,255,0.45);
  line-height: 1.7;
  max-width: 260px;
}
.footer-col h4 {
  font-size: 12px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--green-300);
  font-weight: 700;
  margin-bottom: 16px;
}
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.footer-col ul li a {
  font-size: 13.5px;
  color: rgba(255,255,255,0.5);
  transition: color 0.2s;
}
.footer-col ul li a:hover { color: #fff; }
.footer-bottom {
  max-width: 1100px;
  margin: 0 auto;
  border-top: 1px solid rgba(255,255,255,0.07);
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12.5px;
  color: rgba(255,255,255,0.3);
  flex-wrap: wrap;
  gap: 12px;
}
.footer-bottom a { color: var(--green-300); }

/* ===== CLASS PAGE ===== */
.class-hero {
  background: linear-gradient(135deg, var(--green-900) 0%, var(--green-700) 100%);
  padding: 80px 40px 60px;
  position: relative;
  overflow: hidden;
}
.class-hero::before {
  content: attr(data-class-bg);
  position: absolute;
  right: 40px; top: 50%;
  transform: translateY(-50%);
  font-family: 'Playfair Display', serif;
  font-size: 160px;
  font-weight: 900;
  color: rgba(255,255,255,0.04);
  pointer-events: none;
}
.class-hero-inner { max-width: 1100px; margin: 0 auto; }
.class-hero .breadcrumb {
  font-size: 12px;
  color: rgba(255,255,255,0.4);
  margin-bottom: 16px;
}
.class-hero .breadcrumb a { color: var(--green-300); }
.class-hero h1 {
  font-family: 'Playfair Display', serif;
  font-size: clamp(32px, 6vw, 56px);
  color: #fff;
  margin-bottom: 10px;
}
.class-hero p { color: rgba(255,255,255,0.65); font-size: 15px; max-width: 520px; }

/* Sub-tabs bar */
.subtabs-bar {
  background: var(--white);
  border-bottom: 2px solid var(--cream-dark);
  position: sticky;
  top: var(--nav-height);
  z-index: 100;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.subtabs-bar::-webkit-scrollbar { height: 3px; }
.subtabs-bar::-webkit-scrollbar-thumb { background: var(--green-300); }
.subtabs-inner {
  display: flex;
  gap: 0;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
  min-width: max-content;
}
.subtab {
  padding: 16px 18px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-light);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all 0.2s;
  white-space: nowrap;
  margin-bottom: -2px;
  background: none;
  border-left: none; border-right: none; border-top: none;
  font-family: 'DM Sans', sans-serif;
}
.subtab:hover { color: var(--green-600); }
.subtab.active { color: var(--green-600); border-bottom-color: var(--green-500); }

/* Chapter grid */
.chapter-section { padding: 48px 40px 80px; max-width: 1100px; margin: 0 auto; }
.chapter-section h2 {
  font-family: 'Playfair Display', serif;
  font-size: 26px;
  margin-bottom: 24px;
  color: var(--text-dark);
}
.chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
}
.chapter-card {
  background: var(--white);
  border-radius: 12px;
  padding: 20px 22px;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  box-shadow: var(--shadow);
  transition: all 0.2s;
  cursor: pointer;
  border: 1.5px solid transparent;
}
.chapter-card:hover {
  border-color: var(--green-300);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}
.chapter-num {
  width: 38px; height: 38px;
  background: var(--green-100);
  color: var(--green-700);
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700;
  font-size: 14px;
  flex-shrink: 0;
}
.chapter-info { flex: 1; }
.chapter-name { font-weight: 600; font-size: 14px; color: var(--text-dark); margin-bottom: 4px; }
.chapter-meta { font-size: 12px; color: var(--text-light); }
.chapter-arrow { color: var(--green-400); font-size: 18px; margin-top: 2px; }

/* Content panel */
.content-panel { display: none; }
.content-panel.active { display: block; }

/* ===== CHAPTER PAGE ===== */
.chapter-hero {
  background: linear-gradient(135deg, var(--green-800), var(--green-600));
  padding: 72px 40px 48px;
}
.chapter-hero-inner { max-width: 1100px; margin: 0 auto; }

.resource-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  padding: 40px;
  max-width: 1100px;
  margin: 0 auto;
}
.resource-card {
  background: var(--white);
  border-radius: 12px;
  padding: 22px;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 16px;
  transition: all 0.2s;
  cursor: pointer;
  border-left: 4px solid transparent;
}
.resource-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.resource-icon {
  width: 46px; height: 46px;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px;
  flex-shrink: 0;
}
.resource-info .resource-name { font-weight: 600; font-size: 14px; color: var(--text-dark); }
.resource-info .resource-desc { font-size: 12px; color: var(--text-light); margin-top: 2px; }
.resource-tag {
  margin-left: auto;
  font-size: 10px;
  padding: 3px 8px;
  border-radius: 4px;
  font-weight: 700;
  flex-shrink: 0;
}

/* Color variants for resource cards */
.rc-notes { border-left-color: #3498db; } .rc-notes .resource-icon { background: #e8f4fd; }
.rc-mcq { border-left-color: #9b59b6; } .rc-mcq .resource-icon { background: #f4e8fd; }
.rc-diagram { border-left-color: #e67e22; } .rc-diagram .resource-icon { background: #fdf0e8; }
.rc-practical { border-left-color: #1abc9c; } .rc-practical .resource-icon { background: #e8fdf7; }
.rc-pyq { border-left-color: #e74c3c; } .rc-pyq .resource-icon { background: #fde8e8; }
.rc-mindmap { border-left-color: #27ae60; } .rc-mindmap .resource-icon { background: #e8fdf0; }
.rc-worksheet { border-left-color: #f39c12; } .rc-worksheet .resource-icon { background: #fdf5e8; }
.rc-case { border-left-color: #8e44ad; } .rc-case .resource-icon { background: #f5e8fd; }
.rc-hots { border-left-color: #c0392b; } .rc-hots .resource-icon { background: #fdeae8; }
.rc-flash { border-left-color: #16a085; } .rc-flash .resource-icon { background: #e8f9f7; }
.rc-table { border-left-color: #2980b9; } .rc-table .resource-icon { background: #e8f2fd; }
.rc-mnemonic { border-left-color: #d35400; } .rc-mnemonic .resource-icon { background: #fdf0e8; }

/* ===== ANIMATIONS ===== */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== RESPONSIVE ===== */
@media (max-width: 900px) {
  .about-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .about-image-box { height: 280px; }
}
@media (max-width: 768px) {
  .navbar { padding: 0 20px; }
  .nav-links { display: none; }
  .hamburger { display: flex; }
  .section { padding: 60px 20px; }
  .hero { padding: 60px 20px 40px; }
  .class-hero { padding: 60px 20px 40px; }
  .chapter-section { padding: 32px 20px 60px; }
  .resource-grid { padding: 24px 20px; }
  .footer { padding: 48px 20px 24px; }
  .footer-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }

  /* ── LOGO FIX: About section logo on mobile ── */
  .about-image-box {
    height: 260px;
  }
  .about-image-box img {
    position: relative;        /* ensures z-index is respected on all mobile browsers */
    z-index: 2;
    width: auto !important;
    max-width: 85% !important;
    max-height: 220px !important;
    object-fit: contain !important;
    mix-blend-mode: lighten !important;
    display: block !important;
    visibility: visible !important;
  }

  /* ── LOGO FIX: Nav bar logo image (if components.js injects an <img>) ── */
  .nav-logo img {
    width: 36px;
    height: 36px;
    object-fit: contain;
    display: block;
    flex-shrink: 0;
  }
  .nav-logo {
    font-size: 18px;
    gap: 8px;
  }

  /* ── PWA / badge fix: about badge doesn't overflow on single-column layout ── */
  .about-badge {
    right: 8px;
    bottom: -12px;
    font-size: 16px;
    padding: 10px 14px;
  }
}
@media (max-width: 480px) {
  .hero-stats { gap: 24px; }
  .hero-btns { flex-direction: column; align-items: center; }

  /* Extra small screens: about logo box compact */
  .about-image-box {
    height: 220px;
  }
  .about-image-box img {
    max-height: 180px !important;
  }
}