/* Reset Styles */
body {
  font-family: 'Open Sans', Arial, Helvetica, sans-serif;
  line-height: 1.6;
  color: var(--text-dark);
  background: var(--off-white);
  margin: 0;
}
.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Root Variables */
:root {
  --primary: #6a1b9a;
  --primary-light: #9c4dcc;
  --primary-dark: #38006b;
  --accent: #f3e5f5;
  --white: #fff;
  --off-white: #f9f9f9;
  --text-dark: #333;
  --text-medium: #555;
  --text-light: #777;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* General Styles */
.ad-container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 0;
    min-height: 280px;
    display: flex;
    justify-content: center;
    align-items: center;
}
.adsbygoogle {
    min-height: 280px;
    max-width: 100%;
    box-sizing: border-box;
    display: block;
    text-align: center;
    margin: 2rem 0;
}
@media (max-width: 768px) {
    .adsbygoogle {
        min-height: 90px;
    }
    .ad-container {
        min-height: 90px;
    }
}
.ad-container .adsbygoogle:empty {
    display: none;
}
.ad-placeholder {
    display: block;
}
.adsbygoogle:not(:empty) + .ad-placeholder {
    display: none;
}
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}
.main-nav {
  background: var(--primary);
  box-shadow: var(--shadow-md);
  position: relative;
}
.nav-list {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-list a {
  display: block;
  padding: 16px 20px;
  color: var(--white);
  text-decoration: none;
  text-transform: uppercase;
  font-size: 100%;
  font-weight: 600;
  letter-spacing: 0.5px;
  transition: all 0.3s ease;
  text-align: center;
}
.nav-list a:hover,
.nav-list a.active {
  background: var(--white);
  color: var(--primary);
}
.has-submenu {
  position: relative;
}
.submenu {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
  background: var(--white);
  border: 1px solid var(--text-light);
  box-shadow: var(--shadow-sm);
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  z-index: 1000;
}
.submenu.active {
  display: block;
}
.submenu a {
  padding: 12px 20px;
  color: var(--text-dark);
  text-align: left;
  text-transform: none;
  font-size: 13px;
  font-weight: 500;
}
.submenu a:hover,
.submenu a.active {
  background: var(--off-white);
  color: var(--primary-dark);
}
.hero {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-light));
  color: var(--white);
  padding: 60px 0;
  text-align: center;
}
.hero h1 {
  font-family: Voltaire, Arial, sans-serif;
  font-size: 2.5rem;
  margin-bottom: 20px;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  color: var(--white);
}
.content-card {
  background: var(--white);
  border-radius: 8px;
  padding: 30px;
  margin: 3rem 0;
  box-shadow: var(--shadow-sm);
  border-top: 4px solid var(--primary-light);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.content-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}
.content-card h2 {
  color: var(--primary-dark);
  margin-bottom: 15px;
  font-size: 1.8rem;
}
.content-card h3 {
  color: var(--primary);
  margin: 20px 0 10px;
  font-size: 1.3rem;
}
.content-card p {
  color: var(--text-medium);
  margin-bottom: 15px;
}
.app-promo {
  background: linear-gradient(135deg, var(--primary-light), var(--primary-dark));
  border-radius: 10px;
  padding: 40px;
  margin: 40px 0;
  text-align: center;
  color: var(--white);
}
.app-promo h2 {
  color: var(--white);
  margin-bottom: 20px;
}
.app-download {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 30px;
  flex-wrap: wrap;
}
.app-links {
  display: flex;
  flex-direction: column;
  gap: 15px;
}
.site-footer {
  background: var(--primary-dark);
  color: var(--white);
  padding: 30px 0;
  text-align: center;
}
.footer-content a {
  color: var(--accent);
  text-decoration: none;
  margin: 0 10px;
  transition: color 0.3s ease;
}
.footer-content a:hover {
  color: var(--white);
}
.copyright {
  margin-top: 15px;
  font-size: 14px;
  color: var(--accent);
}
.menu-toggle {
    display: none;
}
h3, h4, h5 {
    display: block;
    margin-bottom: 15px;
}
.exam-boards {
    display: block;
    margin-top: 10px;
}
.breadcrumb-container {
    background-color: var(--off-white);
    padding: 10px 0;
    margin-bottom: 30px;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}
.breadcrumb {
    padding: 0;
    margin: 0;
    background: transparent;
    border-radius: 0;
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    white-space: nowrap;
    list-style: none;
}
.breadcrumb-item {
    font-size: 0.85rem;
    white-space: nowrap;
}
.breadcrumb-item a {
    color: var(--primary-light);
    text-decoration: none;
}
.breadcrumb-item.active {
    color: var(--text-medium);
}
.breadcrumb-item + .breadcrumb-item::before {
    content: ">";
    color: var(--text-light);
    padding: 0 5px;
}
.table-container {
    overflow-x: auto;
    margin: 20px 0;
    -webkit-overflow-scrolling: touch;
}
.subject-buttons, .subcategories, .gcse-tiers, .exam-boards, .past-papers {
    margin: 20px 0;
}
.subcategories, .gcse-tiers, .exam-boards, .past-papers {
    display: none;
}
.subcategories.active, .gcse-tiers.active, .exam-boards.active, .past-papers.active {
    display: block;
    margin: 20px 0;
}
.subject-btn, .subcategory-btn, .tier-btn, .board-btn, .paper-btn {
    padding: 12px 25px;
    border-radius: 6px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    text-align: center;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    width: 100%;
    max-width: 300px;
    margin-bottom: 10px;
    border: none;
    cursor: pointer;
    font-size: 0.9rem;
}
.subject-btn:hover, .subcategory-btn:hover, .tier-btn:hover, .board-btn:hover, .paper-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}
.subject-btn.maths, .subcategory-btn.ks1, .subcategory-btn.as-level, .tier-btn.foundation, .board-btn.ocr, .paper-btn.core1 {
    background-color: #28a745;
    color: var(--white);
}
.subject-btn.science, .subcategory-btn.ks2, .subcategory-btn.a2-level, .tier-btn.intermediate, .board-btn.edexcel, .paper-btn.core2, .paper-btn.discrete {
    background-color: #17a2b8;
    color: var(--white);
}
.subcategory-btn.ks3, .subcategory-btn.a-level, .tier-btn.higher, .board-btn.aqa, .paper-btn.core3, .paper-btn.mechanics1, .paper-btn.maths, .paper-btn.statistics {
    background-color: #007bff;
    color: var(--white);
}
.subcategory-btn.gcse, .paper-btn.statistics1, .paper-btn.mechanics {
    background-color: #dc3545;
    color: var(--white);
}
.subcategory-btn.igcse, .paper-btn.core4, .paper-btn.furthermaths {
    background-color: #ffc107;
    color: #212529;
}
.board-btn.aqa-as {
    background-color: #28a745;
    color: var(--white);
}
.paper-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 30px;
}
.paper-item {
    background: var(--white);
    border-radius: 8px;
    padding: 20px;
    box-shadow: var(--shadow-sm);
    border-top: 4px solid var(--primary-light);
    transition: all 0.3s ease;
}
.paper-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}
.download-btn {
    background-color: var(--primary-light);
    color: var(--white);
    padding: 8px 15px;
    border-radius: 4px;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s ease;
}
.download-btn:hover {
    background-color: var(--primary-dark);
}
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
    background: 0 0;
    border: none;
    cursor: pointer;
  }
  .hamburger {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--primary);
    position: relative;
  }
  .hamburger::before,
  .hamburger::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 3px;
    background: var(--primary);
    left: 0;
  }
  .hamburger::before {
    top: -8px;
  }
  .hamburger::after {
    bottom: -8px;
  }
  .main-nav {
    position: relative;
  }
  .nav-list {
    flex-direction: column;
    display: none;
    position: absolute;
    width: 100%;
    background: var(--primary-dark);
    top: 100%;
    left: 0;
    z-index: 999;
  }
  .nav-list.active {
    display: flex;
  }
  .nav-list li {
    width: 100%;
  }
  .nav-list a {
    padding: 15px;
    text-align: left;
  }
  .submenu {
    position: static;
    width: 100%;
    border: none;
    box-shadow: none;
    background: var(--primary-dark);
  }
  .submenu a {
    color: var(--white);
    padding-left: 30px;
  }
  .submenu a:hover,
  .submenu a.active {
    background: var(--primary);
    color: var(--white);
  }
  .hero h1 {
    font-size: 2rem;
  }
  .content-card {
    padding: 20px;
    margin: 2rem 0;
  }
  .app-download {
    flex-direction: column;
  }
  .container,
  .ad-container {
    padding: 0 10px;
  }
  .contentBox {
    padding: 15px;
    margin-bottom: 20px;
  }
  .subject-buttons,
  .subcategories,
  .gcse-tiers,
  .exam-boards,
  .past-papers {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    max-width: 100%;
    overflow-x: auto;
    scrollbar-width: none;
  }
  .subject-buttons::-webkit-scrollbar,
  .subcategories::-webkit-scrollbar,
  .gcse-tiers::-webkit-scrollbar,
  .exam-boards::-webkit-scrollbar,
  .past-papers::-webkit-scrollbar {
    display: none;
  }
  .subject-btn,
  .subcategory-btn,
  .tier-btn,
  .board-btn,
  .paper-btn {
    width: 100%;
    max-width: 100%;
    min-width: 0;
    padding: 10px 15px;
    font-size: 0.85rem;
  }
  .paper-grid {
    grid-template-columns: 1fr;
  }
  .breadcrumb {
    font-size: 0.8rem;
  }
  .breadcrumb-item {
    font-size: 0.8rem;
  }
  .breadcrumb-item + .breadcrumb-item::before {
    padding: 0 3px;
  }
}
@media (max-width: 360px) {
  .container,
  .ad-container {
    padding: 0 5px;
  }
  .subject-btn,
  .subcategory-btn,
  .tier-btn,
  .board-btn,
  .paper-btn {
    padding: 8px 10px;
    font-size: 0.8rem;
  }
  .contentBox {
    padding: 10px;
  }
}

/* Component-Specific Styles */
.site-header {
  background: var(--white);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
}
.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 0;
}
.logo {
  height: 50px;
  width: 150px;
  object-fit: contain;
  transition: transform 0.3s ease;
}
.logo:hover {
  transform: scale(1.05);
}
.app-icon img, .app-links img {
    width: 100%;
    height: auto;
    aspect-ratio: attr(width) / attr(height);
}