/* ==========================================================================
   Forsko - PYQs Semester I Stylesheet
   Theme: Dark Navy (#0F172A) | Sky Blue (#3B82F6) | Glassmorphism Cards
   ========================================================================== */

:root {
  --dark-navy: #0F172A;
  --dark-navy-card: rgba(30, 41, 59, 0.7);
  --dark-navy-deep: #0B1120;
  --sky-blue: #3B82F6;
  --sky-blue-hover: #2563EB;
  --sky-blue-light: rgba(59, 130, 246, 0.15);
  --white: #FFFFFF;
  --border-glass: rgba(255, 255, 255, 0.12);
  --text-muted: #94A3B8;

  /* Status Badges */
  --status-green: #10B981;
  --status-green-bg: rgba(16, 185, 129, 0.15);
  --status-green-border: rgba(16, 185, 129, 0.3);

  --status-orange: #F59E0B;
  --status-orange-bg: rgba(245, 158, 11, 0.15);
  --status-orange-border: rgba(245, 158, 11, 0.3);

  --status-red: #EF4444;
  --status-red-bg: rgba(239, 68, 68, 0.15);
  --status-red-border: rgba(239, 68, 68, 0.3);

  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 10px 20px -3px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 20px 30px -5px rgba(0, 0, 0, 0.4);
  --blue-glow: 0 0 25px rgba(59, 130, 246, 0.35);

  --transition-fast: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: all 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--dark-navy-deep);
  color: var(--white);
  line-height: 1.6;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition-fast);
}

ul {
  list-style: none;
}

.hidden {
  display: none !important;
}

/* ==========================================================================
   1. Sticky Navigation Bar
   ========================================================================== */

.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(15, 23, 42, 0.92);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  transition: var(--transition-fast);
}

.navbar.scrolled {
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 74px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--white);
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background-color: var(--sky-blue);
  color: var(--white);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
}

.logo-image {
    width: 140px;
    height: 140px;
    object-fit: contain;
}

.logo span {
    font-size: 1.5rem;
    font-weight: 700;
    color: #fff;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
  padding: 6px 0;
}

.nav-link:hover, .nav-link.active {
  color: var(--white);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background-color: var(--sky-blue);
  transition: var(--transition-fast);
}

.nav-link:hover::after, .nav-link.active::after {
  width: 100%;
}

.hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--white);
  font-size: 1.5rem;
  cursor: pointer;
}

/* ==========================================================================
   2. Hero Section
   ========================================================================== */

.page-hero {
  position: relative;
  background: radial-gradient(circle at top center, #1E293B, var(--dark-navy));
  padding: 70px 24px 50px 24px;
  text-align: center;
  overflow: hidden;
  border-bottom: 1px solid var(--border-glass);
}

.hero-glow {
  position: absolute;
  top: -50px;
  left: 50%;
  transform: translateX(-50%);
  width: 500px;
  height: 300px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.25) 0%, transparent 70%);
  pointer-events: none;
}

.hero-container {
  max-width: 850px;
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

.breadcrumb {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  background-color: rgba(255, 255, 255, 0.05);
  padding: 6px 18px;
  border-radius: 30px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  flex-wrap: wrap;
  justify-content: center;
}

.breadcrumb a {
  color: var(--text-muted);
}

.breadcrumb a:hover {
  color: var(--sky-blue);
}

.breadcrumb .separator {
  font-size: 0.7rem;
}

.breadcrumb span {
  color: var(--white);
  font-weight: 600;
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  color: var(--white);
  letter-spacing: -1px;
  margin-bottom: 12px;
}

.hero-subtitle {
  margin-bottom: 10px;
}

.institution-meta {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.5;
}

.institution-meta.university {
  color: var(--sky-blue);
  font-weight: 600;
}

/* ==========================================================================
   3. Search Section
   ========================================================================== */

.search-section {
  padding: 30px 24px 10px 24px;
  background-color: var(--dark-navy);
}

.search-container {
  max-width: 1000px;
  margin: 0 auto;
}

.search-box {
  position: relative;
  display: flex;
  align-items: center;
  background: var(--dark-navy-card);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-glass);
  border-radius: 14px;
  padding: 6px 18px;
  transition: var(--transition-fast);
  box-shadow: var(--shadow-sm);
}

.search-box:focus-within {
  border-color: var(--sky-blue);
  box-shadow: var(--blue-glow);
}

.search-icon {
  color: var(--text-muted);
  font-size: 1.1rem;
  margin-right: 12px;
}

.search-box input {
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  color: var(--white);
  font-size: 1rem;
  font-family: inherit;
  padding: 12px 0;
}

.search-box input::placeholder {
  color: var(--text-muted);
}

.search-clear-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1rem;
  cursor: pointer;
  padding: 6px;
  transition: var(--transition-fast);
}

.search-clear-btn:hover {
  color: var(--white);
}

/* ==========================================================================
   4. PYQ Accordion Section
   ========================================================================== */

.pyq-section {
  padding: 30px 24px 90px 24px;
  background-color: var(--dark-navy);
}

.pyq-container {
  max-width: 1000px;
  margin: 0 auto;
}

.subject-accordions-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.subject-accordion-card {
  background: var(--dark-navy-card);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-glass);
  border-radius: 16px;
  overflow: hidden;
  transition: var(--transition-smooth);
  box-shadow: var(--shadow-sm);
}

.subject-accordion-card:hover {
  border-color: rgba(59, 130, 246, 0.4);
  box-shadow: var(--shadow-lg), var(--blue-glow);
  transform: translateY(-4px);
}

.subject-accordion-card.open {
  border-color: var(--sky-blue);
  box-shadow: var(--shadow-lg), var(--blue-glow);
}

/* Accordion Header */
.accordion-header {
  padding: 24px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  cursor: pointer;
  -webkit-user-select: none;
  user-select: none;
}

.subject-info {
  display: flex;
  align-items: center;
  gap: 20px;
  flex: 1;
}

.subject-icon-box {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background-color: var(--sky-blue-light);
  color: var(--sky-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  flex-shrink: 0;
  transition: var(--transition-fast);
}

.subject-accordion-card:hover .subject-icon-box,
.subject-accordion-card.open .subject-icon-box {
  background-color: var(--sky-blue);
  color: var(--white);
}

.subject-text {
  flex: 1;
}

.subject-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 4px;
}

.subject-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--white);
  line-height: 1.3;
}

.papers-count-badge {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--sky-blue);
  background-color: rgba(59, 130, 246, 0.12);
  padding: 4px 12px;
  border-radius: 20px;
  border: 1px solid rgba(59, 130, 246, 0.25);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.subject-description {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.5;
}

/* Toggle Button */
.accordion-toggle-btn {
  background-color: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-glass);
  color: var(--white);
  padding: 10px 18px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 10px;
  transition: var(--transition-fast);
  flex-shrink: 0;
}

.accordion-toggle-btn:hover {
  background-color: var(--sky-blue);
  border-color: var(--sky-blue);
}

.toggle-icon {
  transition: transform 0.35s cubic-bezier(0.16, 1, 0.3, 1);
  font-size: 0.85rem;
}

.subject-accordion-card.open .toggle-icon {
  transform: rotate(180deg);
}

/* Accordion Content Smooth Transition */
.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.3s ease;
  opacity: 0;
}

.subject-accordion-card.open .accordion-content {
  opacity: 1;
}

.accordion-inner {
  padding: 0 28px 28px 28px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  margin-top: 4px;
  padding-top: 24px;
}

/* Papers Grid Inside Accordion */
.papers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

/* Individual Paper Card */
.paper-card {
  background-color: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition-fast);
}

.paper-card:hover {
  transform: translateY(-3px);
  border-color: rgba(59, 130, 246, 0.3);
  box-shadow: var(--shadow-md);
  background-color: rgba(15, 23, 42, 0.85);
}

.paper-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

.year-badge {
  font-size: 0.85rem;
  font-weight: 800;
  color: var(--white);
  background-color: rgba(255, 255, 255, 0.1);
  padding: 2px 10px;
  border-radius: 6px;
}

/* Status Badges */
.status-badge {
  font-size: 0.78rem;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 20px;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.status-available {
  color: var(--status-green);
  background-color: var(--status-green-bg);
  border: 1px solid var(--status-green-border);
}

.status-coming-soon {
  color: var(--status-orange);
  background-color: var(--status-orange-bg);
  border: 1px solid var(--status-orange-border);
}

.status-not-available {
  color: var(--status-red);
  background-color: var(--status-red-bg);
  border: 1px solid var(--status-red-border);
}

.paper-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 16px;
}

.paper-actions {
  display: flex;
  gap: 10px;
}

.paper-btn {
  flex: 1;
  padding: 9px 14px;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  cursor: pointer;
  border: none;
  transition: var(--transition-fast);
}

.btn-preview {
  background-color: rgba(255, 255, 255, 0.08);
  color: var(--white);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.btn-preview:hover {
  background-color: rgba(255, 255, 255, 0.18);
  border-color: rgba(255, 255, 255, 0.3);
}

.btn-download {
  background-color: var(--sky-blue);
  color: var(--white);
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.25);
}

.btn-download:hover {
  background-color: var(--sky-blue-hover);
  box-shadow: var(--blue-glow);
}

.btn-disabled {
  background-color: rgba(255, 255, 255, 0.05);
  color: var(--text-muted);
  border: 1px solid rgba(255, 255, 255, 0.08);
  cursor: not-allowed;
  width: 100%;
}

/* Empty Search State */
.no-results-state {
  text-align: center;
  padding: 60px 20px;
  background: var(--dark-navy-card);
  border: 1px solid var(--border-glass);
  border-radius: 16px;
  color: var(--text-muted);
}

.no-results-state i {
  font-size: 3rem;
  color: var(--sky-blue);
  margin-bottom: 16px;
}

.no-results-state h3 {
  font-size: 1.3rem;
  color: var(--white);
  margin-bottom: 8px;
}

/* ==========================================================================
   5. Footer Section
   ========================================================================== */

.footer {
  background-color: var(--dark-navy-deep);
  color: var(--white);
  padding: 80px 24px 30px 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1.2fr 1.2fr;
  gap: 40px;
  padding-bottom: 50px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-col.brand-col p {
  color: var(--text-muted);
  margin-top: 16px;
  font-size: 0.95rem;
  line-height: 1.6;
}

.footer-col h3 {
  font-size: 1.05rem;
  margin-bottom: 20px;
}

.footer-col ul li {
  margin-bottom: 12px;
}

.footer-col ul a {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.footer-col ul a:hover {
  color: var(--sky-blue);
  padding-left: 4px;
}

.contact-list li {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.contact-list i {
  color: var(--sky-blue);
}

.community-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.github-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background-color: rgba(255, 255, 255, 0.08);
  color: var(--white);
  padding: 10px 18px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9rem;
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.github-btn:hover {
  background-color: var(--sky-blue);
  border-color: var(--sky-blue);
}

.footer-bottom {
  text-align: center;
  padding-top: 30px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ==========================================================================
   6. Responsive Media Queries
   ========================================================================== */

@media (max-width: 1024px) {
  .footer-container {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .hamburger {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: 74px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 74px);
    background-color: var(--dark-navy);
    flex-direction: column;
    padding: 40px 24px;
    gap: 20px;
    transition: var(--transition-smooth);
  }

  .nav-menu.active {
    left: 0;
  }

  .hero-title {
    font-size: 2.2rem;
  }

  .accordion-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .accordion-toggle-btn {
    width: 100%;
    justify-content: center;
  }

  .papers-grid {
    grid-template-columns: 1fr;
  }

  .footer-container {
    grid-template-columns: 1fr;
  }
}