/*
 * Gateway Classes — Shared Responsive UI v2.0
 * All pages include this file for consistent, mobile-first design.
 * Covers: 1year / 2ndyear / 3year / multiatom / lectindex / under / viewer
 * ====================================================================
 */

/* ── CSS Variables ───────────────────────────────────────────────── */
:root {
  --bg:          #060913;
  --bg2:         #0a1220;
  --card-bg:     rgba(10, 18, 35, 0.88);
  --accent:      #00eaff;
  --accent2:     #00ffcc;
  --accent-gold: #f59e0b;
  --border:      rgba(0, 234, 255, 0.22);
  --text:        #e2f1f8;
  --muted:       #94a3b8;
  --font-head:   'Orbitron', sans-serif;
  --font-body:   'Poppins', sans-serif;
  --r-card:      14px;
  --r-input:     12px;
  --safe-b:      env(safe-area-inset-bottom, 0px);
}

/* ── Base Reset ─────────────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  min-height: 100vh;
  width: 100%;
  max-width: 100vw;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img, iframe, video {
  max-width: 100%;
  display: block;
}

/* ── Back Button (common across pages) ──────────────────────────── */
#gwcHomeBtn {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border-radius: 10px;
  background: rgba(10, 18, 35, 0.92);
  border: 1px solid rgba(0, 234, 255, 0.35);
  color: var(--accent);
  font-family: var(--font-body);
  font-size: clamp(11px, 2.8vw, 13px);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.45);
  transition: .22s ease;
  white-space: nowrap;
  max-width: calc(100vw - 24px);
}
#gwcHomeBtn:hover {
  background: rgba(0, 234, 255, 0.14);
  border-color: var(--accent);
  box-shadow: 0 0 18px rgba(0, 234, 255, 0.35);
  transform: translateY(-1px);
}

/* ── Page Header ────────────────────────────────────────────────── */
.hub-header {
  text-align: center;
  padding: clamp(56px, 10vw, 72px) clamp(12px, 4vw, 24px) clamp(12px, 2.5vw, 20px);
  width: 100%;
}

.badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 16px;
  border-radius: 999px;
  background: rgba(0, 234, 255, 0.1);
  border: 1px solid rgba(0, 234, 255, 0.35);
  color: var(--accent);
  font-size: clamp(10px, 2.2vw, 12px);
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 10px;
  box-shadow: 0 0 14px rgba(0, 234, 255, 0.22);
  font-family: var(--font-head);
}

h1 {
  font-family: var(--font-head);
  font-size: clamp(1.4rem, 5vw, 2.4rem);
  font-weight: 800;
  color: #ffffff;
  letter-spacing: 1px;
  text-shadow: 0 0 22px rgba(0, 234, 255, 0.6);
  margin: 0 0 8px;
  line-height: 1.25;
  word-break: break-word;
}

.hub-subtitle {
  font-size: clamp(12.5px, 2.5vw, 14.5px);
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.55;
  word-break: break-word;
}
.hub-subtitle b { color: var(--accent); }

/* Stats row */
.stats-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 10px;
}
.stat-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: clamp(4px, 1vw, 6px) clamp(10px, 2vw, 14px);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  font-size: clamp(10px, 2.2vw, 12px);
  color: #cbd5e1;
  font-weight: 500;
}

/* ── Main Wrapper ───────────────────────────────────────────────── */
.main-wrap {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: clamp(6px, 2vw, 14px) clamp(12px, 3vw, 20px) clamp(20px, 4vw, 36px);
}

/* ── Search Box ─────────────────────────────────────────────────── */
.search-box-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
  background: rgba(10, 18, 35, 0.9);
  border: 1px solid rgba(0, 234, 255, 0.32);
  border-radius: var(--r-input);
  padding: 4px 12px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.35), 0 0 14px rgba(0, 234, 255, 0.1);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: .25s ease;
}
.search-box-wrapper:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 22px rgba(0, 234, 255, 0.35);
}

.search-icon {
  font-size: 17px;
  margin-right: 9px;
  color: var(--accent);
  flex-shrink: 0;
}

input[type="text"],
#noteSearch,
#subjectSearch {
  flex: 1;
  min-width: 0;
  background: transparent;
  border: none;
  outline: none;
  color: #ffffff;
  font-size: clamp(13px, 2.8vw, 15px);
  padding: 9px 0;
  font-family: var(--font-body);
}
input::placeholder { color: #4a5568; }

.clear-btn {
  background: rgba(255, 255, 255, 0.08);
  border: none;
  color: var(--muted);
  border-radius: 50%;
  width: 26px;
  height: 26px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  transition: .2s;
  flex-shrink: 0;
}
.clear-btn:hover { background: rgba(255,255,255,.18); color: #fff; }

/* ── Filter Chips ───────────────────────────────────────────────── */
.chips-container,
.sem-tabs,
.session-chips {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding: 10px 2px;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.chips-container::-webkit-scrollbar,
.sem-tabs::-webkit-scrollbar,
.session-chips::-webkit-scrollbar { display: none; }

.subject-chip,
.sem-tab-btn,
.session-chip {
  display: inline-flex;
  align-items: center;
  padding: clamp(5px, 1.2vw, 7px) clamp(10px, 2.5vw, 16px);
  border-radius: 999px;
  border: 1px solid rgba(0, 234, 255, 0.3);
  background: rgba(0, 234, 255, 0.06);
  color: var(--accent);
  font-size: clamp(10.5px, 2.2vw, 12.5px);
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: .2s ease;
  font-family: var(--font-body);
  flex-shrink: 0;
}
.subject-chip:hover,
.sem-tab-btn:hover,
.session-chip:hover,
.subject-chip.active,
.sem-tab-btn.active,
.session-chip.active {
  background: rgba(0, 234, 255, 0.18);
  border-color: var(--accent);
  box-shadow: 0 0 12px rgba(0, 234, 255, 0.28);
}

/* ── Notes Grid / Subject List ──────────────────────────────────── */
.notes-grid,
.subjects-list,
#subjectsList {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 280px), 1fr));
  gap: clamp(10px, 2vw, 16px);
  margin: clamp(12px, 2.5vw, 20px) 0;
  width: 100%;
}

/* ── Note Card / Subject Card ───────────────────────────────────── */
.note-card-link,
.subject-card {
  display: flex;
  flex-direction: column;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: clamp(12px, 3vw, 18px);
  text-decoration: none;
  color: var(--text);
  transition: transform .22s ease, border-color .22s ease, box-shadow .22s ease;
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  cursor: pointer;
}
.note-card-link:hover,
.subject-card:hover {
  transform: translateY(-3px);
  border-color: rgba(0, 234, 255, 0.5);
  box-shadow: 0 8px 24px rgba(0, 234, 255, 0.18);
}
.note-card-link:active,
.subject-card:active { transform: scale(.98); }

.note-icon,
.subject-icon {
  font-size: clamp(20px, 4.5vw, 26px);
  margin-bottom: clamp(6px, 1.5vw, 10px);
}

.note-name,
.subject-title {
  font-weight: 600;
  font-size: clamp(12.5px, 2.5vw, 14px);
  color: var(--text);
  line-height: 1.4;
  margin-bottom: 4px;
  word-break: break-word;
}

.note-meta,
.subject-meta {
  font-size: clamp(10.5px, 2vw, 12px);
  color: var(--muted);
  margin-top: auto;
  padding-top: 6px;
}

/* Accent stripe on left edge of card */
.note-card-link::before,
.subject-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 3px;
  height: 100%;
  background: linear-gradient(to bottom, var(--accent), transparent);
  opacity: 0;
  transition: opacity .2s ease;
  border-radius: 14px 0 0 14px;
}
.note-card-link:hover::before,
.subject-card:hover::before { opacity: 1; }

/* Download / Access button inside card */
.note-download-btn,
.subject-link-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  margin-top: 10px;
  padding: clamp(6px, 1.5vw, 8px) clamp(12px, 3vw, 16px);
  border-radius: 9px;
  background: rgba(0, 234, 255, 0.1);
  border: 1px solid rgba(0, 234, 255, 0.32);
  color: var(--accent);
  font-size: clamp(11px, 2.2vw, 13px);
  font-weight: 600;
  text-decoration: none;
  transition: .2s ease;
  width: 100%;
  cursor: pointer;
  font-family: var(--font-body);
}
.note-download-btn:hover,
.subject-link-btn:hover {
  background: var(--accent);
  color: #030712;
  box-shadow: 0 0 14px rgba(0, 234, 255, 0.5);
}

/* Unit tabs / section headers */
.unit-tabs {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin: 12px 0 8px;
}

.unit-tab {
  padding: 5px 13px;
  border-radius: 999px;
  border: 1px solid rgba(0, 234, 255, 0.28);
  background: rgba(0, 234, 255, 0.06);
  color: var(--accent);
  font-size: clamp(11px, 2.2vw, 12.5px);
  font-weight: 600;
  cursor: pointer;
  transition: .2s;
  font-family: var(--font-body);
}
.unit-tab:hover, .unit-tab.active {
  background: rgba(0, 234, 255, 0.18);
  border-color: var(--accent);
}

/* ── Section Divider / Label ────────────────────────────────────── */
.section-label {
  font-family: var(--font-head);
  font-size: clamp(11px, 2.5vw, 13px);
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin: clamp(16px, 3vw, 22px) 0 clamp(8px, 1.5vw, 12px);
  display: flex;
  align-items: center;
  gap: 8px;
}
.section-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(to right, rgba(0,234,255,.3), transparent);
  max-width: 200px;
}

/* ── Paper Card (under.html) ────────────────────────────────────── */
.paper-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: clamp(12px, 3vw, 16px);
  cursor: pointer;
  transition: .22s ease;
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(10px);
}
.paper-card:hover {
  border-color: rgba(0, 234, 255, 0.5);
  box-shadow: 0 6px 22px rgba(0, 234, 255, 0.16);
  transform: translateY(-2px);
}
.paper-card:active { transform: scale(.98); }

.paper-title {
  font-size: clamp(12px, 2.5vw, 13.5px);
  font-weight: 600;
  color: var(--text);
  line-height: 1.4;
  margin-bottom: 5px;
  word-break: break-word;
}

.paper-meta {
  font-size: clamp(10px, 2vw, 11.5px);
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  align-items: center;
}

.paper-tag {
  padding: 2px 8px;
  border-radius: 999px;
  background: rgba(0, 234, 255, 0.08);
  border: 1px solid rgba(0, 234, 255, 0.2);
  color: var(--accent);
  font-size: 10px;
  font-weight: 600;
}

.paper-download-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-top: 10px;
  padding: 6px 14px;
  border-radius: 8px;
  background: linear-gradient(135deg, #f59e0b, #d97706);
  color: #050816;
  font-weight: 700;
  font-size: clamp(11px, 2.2vw, 13px);
  border: none;
  cursor: pointer;
  transition: .2s;
  width: 100%;
  justify-content: center;
  font-family: var(--font-body);
}
.paper-download-btn:hover {
  box-shadow: 0 0 16px rgba(245, 158, 11, 0.5);
  transform: translateY(-1px);
}

/* ── Papers Grid ────────────────────────────────────────────────── */
.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 240px), 1fr));
  gap: clamp(10px, 2vw, 14px);
  margin: clamp(10px, 2vw, 16px) 0;
}

/* ── Results Count ──────────────────────────────────────────────── */
.results-count {
  font-size: clamp(11.5px, 2.2vw, 13px);
  color: var(--muted);
  padding: 6px 2px;
}
.results-count span { color: var(--accent); font-weight: 600; }

/* ── No Results ─────────────────────────────────────────────────── */
.no-results {
  text-align: center;
  padding: 40px 20px;
  color: var(--muted);
  font-size: 14px;
  background: rgba(10,18,35,.6);
  border-radius: 14px;
  border: 1px dashed rgba(255,255,255,.12);
  grid-column: 1 / -1;
}

/* ── Load More ──────────────────────────────────────────────────── */
.load-more-container {
  text-align: center;
  padding: clamp(12px, 2.5vw, 20px) 0;
}
.load-more-btn {
  padding: clamp(9px, 2vw, 12px) clamp(24px, 5vw, 36px);
  border-radius: 12px;
  background: rgba(0, 234, 255, 0.1);
  border: 1px solid rgba(0, 234, 255, 0.38);
  color: var(--accent);
  font-size: clamp(13px, 2.5vw, 15px);
  font-weight: 700;
  cursor: pointer;
  transition: .25s ease;
  font-family: var(--font-body);
}
.load-more-btn:hover {
  background: rgba(0, 234, 255, 0.18);
  box-shadow: 0 0 20px rgba(0, 234, 255, 0.35);
}

/* ── Support Footer ─────────────────────────────────────────────── */
.support {
  text-align: center;
  margin: clamp(14px, 3vw, 22px) 0 clamp(10px, 2vw, 16px);
  font-size: clamp(12.5px, 2.5vw, 14px);
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  flex-wrap: wrap;
}
.support img { width: 18px; height: 18px; }
.support a { color: #2563eb; text-decoration: none; font-weight: 600; }
.support a:hover { text-decoration: underline; }

/* ── Ad slot defaults ───────────────────────────────────────────── */
.ad-slot {
  display: block;
  box-sizing: border-box;
  width: 100%;
  max-width: clamp(280px, 100%, 970px);
  margin: clamp(10px, 2vw, 18px) auto;
  text-align: center;
  overflow: hidden;
  min-height: 0;
  clear: both;
}
.ad-slot:empty { display: none !important; margin: 0 !important; }

/* ── Controls Panel (under.html sticky) ────────────────────────── */
.controls-panel {
  background: rgba(6, 9, 19, 0.95);
  border-bottom: 1px solid rgba(0, 234, 255, 0.15);
  padding: clamp(10px, 2vw, 14px) clamp(12px, 3vw, 18px);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  position: sticky;
  top: 0;
  z-index: 100;
}

/* ── Animations ─────────────────────────────────────────────────── */
@keyframes gwcFadeIn {
  from { opacity: 0; transform: translateY(-10px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes gwcFadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes gwcPulse {
  from { box-shadow: 0 0 10px rgba(0,234,255,.3); }
  to   { box-shadow: 0 0 22px rgba(0,234,255,.6); }
}

/* ===================================================================
   RESPONSIVE BREAKPOINTS
   ===================================================================

   ≤ 360px  — ultra-small phones
   ≤ 480px  — standard phones  (2-col where applicable)
   ≤ 680px  — large phones / small landscape
   ≤ 1024px — tablets
   ≥ 1025px — laptops / desktops
   =================================================================== */

/* Ultra-small phones */
@media (max-width: 360px) {
  h1 { font-size: 1.3rem; }
  .hub-header { padding-top: 50px; }
  .notes-grid,
  .papers-grid { grid-template-columns: 1fr; gap: 8px; }
  #gwcHomeBtn { padding: 5px 10px; font-size: 10.5px; }
}

/* Standard phones */
@media (max-width: 480px) {
  .hub-header { padding-top: 58px; }
  .main-wrap  { padding: 6px 12px 22px; }
  /* Notes grid: 1 col on very small, auto on bigger */
  .notes-grid { grid-template-columns: 1fr; }
  .papers-grid { grid-template-columns: 1fr; }
  .controls-panel { padding: 8px 12px; }
}

/* Large phones / small landscape */
@media (min-width: 481px) and (max-width: 680px) {
  .notes-grid  { grid-template-columns: repeat(2, 1fr); }
  .papers-grid { grid-template-columns: repeat(2, 1fr); }
}

/* Tablets */
@media (min-width: 681px) and (max-width: 1024px) {
  .notes-grid  { grid-template-columns: repeat(auto-fill, minmax(min(100%, 260px), 1fr)); }
  .papers-grid { grid-template-columns: repeat(auto-fill, minmax(min(100%, 220px), 1fr)); }
}

/* Landscape short screens */
@media (orientation: landscape) and (max-height: 480px) {
  .hub-header { padding-top: 48px; padding-bottom: 8px; }
  h1 { font-size: 1.3rem; }
  .ad-slot { margin: 4px auto; }
}

/* Print */
@media print {
  .ad-slot, #gwcHomeBtn { display: none !important; }
  body { background: #fff; color: #000; }
}

/* ===================================================================
   PREMIUM POLISH PASS — buttons & small controls (all year pages)
   =================================================================== */

/* Unit tab buttons (injected by JS on 1yr/2yr/3yr/lect pages) */
.unit-tab-btn {
  display: inline-flex;
  align-items: center;
  padding: clamp(5px, 1.2vw, 7px) clamp(10px, 2.4vw, 15px);
  border-radius: 999px;
  border: 1px solid rgba(0, 234, 255, 0.3);
  background: rgba(0, 234, 255, 0.06);
  color: var(--accent);
  font-family: var(--font-body);
  font-size: clamp(10.5px, 2.2vw, 12.5px);
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: .2s ease;
  -webkit-tap-highlight-color: transparent;
}
.unit-tab-btn:hover,
.unit-tab-btn.active {
  background: rgba(0, 234, 255, 0.18);
  border-color: var(--accent);
  box-shadow: 0 0 12px rgba(0, 234, 255, 0.28);
  color: var(--accent);
}
.unit-tab-btn:active { transform: scale(.97); }

/* Expand All / toggle link-style buttons → proper pill buttons */
#toggleAllBtn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-top: 6px;
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid rgba(0, 234, 255, 0.32);
  background: rgba(0, 234, 255, 0.08);
  color: var(--accent);
  font-family: var(--font-body);
  font-size: clamp(11px, 2.2vw, 12.5px);
  font-weight: 600;
  cursor: pointer;
  text-decoration: none !important;
  transition: .2s ease;
  -webkit-tap-highlight-color: transparent;
}
#toggleAllBtn:hover {
  background: rgba(0, 234, 255, 0.18);
  border-color: var(--accent);
  box-shadow: 0 0 12px rgba(0, 234, 255, 0.28);
}

/* Touch targets: every interactive control ≥ 40px tall on phones */
@media (pointer: coarse) {
  .unit-tab-btn, #toggleAllBtn, .clear-btn,
  .subject-chip, .sem-tab-btn, .session-chip, .unit-tab {
    min-height: 40px;
    padding-top: 8px;
    padding-bottom: 8px;
  }
  .clear-btn { width: 34px; height: 34px; }
}

/* Focus rings for keyboard users (premium + accessibility) */
.unit-tab-btn:focus-visible, #toggleAllBtn:focus-visible,
.load-more-btn:focus-visible, .note-download-btn:focus-visible,
.subject-link-btn:focus-visible, .paper-download-btn:focus-visible,
.clear-btn:focus-visible, #gwcHomeBtn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}