@import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@300;400;600;700;900&family=Inter:wght@300;400;500&display=swap');

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

:root {
  --section-color: #f0f4f8;
  --section-grad-a: #e8f0fe;
  --section-grad-b: #f0f4f8;
  --accent: #1565C0;
  --text: #1a2540;
  --text-muted: #5f7080;
  --panel-bg: rgba(255, 255, 255, 0.75);
  --panel-border: rgba(0, 0, 0, 0.10);
  --panel-w: 280px;
  --header-h: 60px;
  --footer-h: 72px;
  --transition-speed: 1.2s;
}

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: 'Inter', sans-serif;
  color: var(--text);
  background: var(--section-color);
  transition: background var(--transition-speed) ease;
}

/* ── Background Canvas ── */
#bg-canvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

/* ── Header ── */
#main-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-h);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--panel-border);
  box-shadow: 0 1px 12px rgba(0, 0, 0, 0.08);
}

.header-logo {
  display: flex;
  align-items: baseline;
  gap: 4px;
  font-family: 'Montserrat', sans-serif;
}

.logo-text {
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--accent);
  letter-spacing: -1px;
}

.logo-year {
  font-size: 0.9rem;
  font-weight: 300;
  color: var(--text-muted);
}

.section-indicator {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: 'Montserrat', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  transition: all 0.4s ease;
}

#section-emoji {
  font-size: 1.3rem;
}

#section-name {
  color: var(--accent);
}

.audio-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

.ctrl-btn {
  width: 36px;
  height: 36px;
  background: rgba(0, 0, 0, 0.06);
  border: 1px solid var(--panel-border);
  border-radius: 50%;
  color: var(--text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  transition: all 0.2s;
}

.ctrl-btn:hover {
  background: rgba(0, 0, 0, 0.12);
  transform: scale(1.1);
}

.ctrl-btn.active {
  background: var(--accent);
  color: #fff;
}

#volume-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 80px;
  height: 3px;
  background: rgba(0, 0, 0, 0.15);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
}

#volume-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  transition: transform 0.2s;
}

#volume-slider::-webkit-slider-thumb:hover {
  transform: scale(1.3);
}

/* ── Main Layout ── */
#main-content {
  position: fixed;
  top: var(--header-h);
  bottom: var(--footer-h);
  left: 0;
  right: 0;
  display: flex;
  align-items: stretch;
  z-index: 1;
  overflow: hidden;
}

/* ── Side Panels ── */
.side-panel {
  width: var(--panel-w);
  flex-shrink: 0;
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  border-color: var(--panel-border);
  padding: 16px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: background 0.6s ease, border-color 0.6s ease;
  scrollbar-width: thin;
  scrollbar-color: var(--panel-border) transparent;
}

#left-panel {
  border-right: 1px solid var(--panel-border);
}

#right-panel {
  border-left: 1px solid var(--panel-border);
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--panel-border);
}

.panel-header h3 {
  font-family: 'Montserrat', sans-serif;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
}

/* ── Poll Cards ── */
.poll-card {
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  padding: 14px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  animation: slideInLeft 0.5s ease forwards;
  transform: translateX(-20px);
  opacity: 0;
}

.poll-card:nth-child(2) {
  animation-delay: 0.15s;
}

@keyframes slideInLeft {
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes slideInRight {
  from {
    transform: translateX(20px);
    opacity: 0;
  }

  to {
    transform: translateX(0);
    opacity: 1;
  }
}

.poll-icon {
  font-size: 1.5rem;
  margin-bottom: 6px;
  display: block;
}

.poll-question {
  font-size: 0.78rem;
  font-weight: 500;
  line-height: 1.4;
  margin-bottom: 10px;
  color: var(--text);
}

.poll-options {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.poll-option-btn {
  background: rgba(0, 0, 0, 0.04);
  border: 1px solid rgba(0, 0, 0, 0.10);
  border-radius: 8px;
  padding: 7px 10px;
  color: var(--text);
  font-size: 0.73rem;
  cursor: pointer;
  text-align: left;
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
  font-family: 'Inter', sans-serif;
}

.poll-option-btn:hover {
  background: rgba(21, 101, 192, 0.1);
  border-color: var(--accent);
  transform: translateX(3px);
}

.poll-option-btn .fill-bar {
  position: absolute;
  inset: 0;
  left: 0;
  top: 0;
  height: 100%;
  width: 0;
  background: rgba(21, 101, 192, 0.12);
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 7px;
}

.poll-option-btn .btn-text {
  position: relative;
  z-index: 1;
}

.poll-option-btn .btn-pct {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.68rem;
  color: var(--accent);
  font-weight: 600;
  opacity: 0;
  transition: opacity 0.4s;
  z-index: 1;
}

.poll-voted .poll-option-btn {
  cursor: default;
}

.poll-voted .poll-option-btn:hover {
  transform: none;
}

.poll-voted .btn-pct {
  opacity: 1;
}

.poll-voted .poll-option-btn.selected {
  border-color: var(--accent);
  background: rgba(79, 195, 247, 0.1);
}

.poll-thanks {
  font-size: 0.72rem;
  color: var(--accent);
  text-align: center;
  margin-top: 8px;
  animation: fadeIn 0.4s ease;
}

/* ── Stat Cards ── */
.stat-card {
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  padding: 14px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  animation: slideInRight 0.5s ease forwards;
  transform: translateX(20px);
  opacity: 0;
}

.stat-card:nth-child(2) {
  animation-delay: 0.1s;
}

.stat-card:nth-child(3) {
  animation-delay: 0.2s;
}

.stat-icon {
  font-size: 1.6rem;
  display: block;
  margin-bottom: 4px;
}

.stat-value {
  font-family: 'Montserrat', sans-serif;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 3px;
}

.stat-label {
  font-size: 0.68rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ── PDF Viewer ── */
#pdf-viewer {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  padding: 16px 0 8px;
}

#book-container {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
}

#book {
  position: relative;
  border-radius: 4px;
  box-shadow: #0000008a 0px 0px 5px;
  transition: box-shadow 0.6s ease;
}

#book:hover {
  box-shadow: #0000008a 0px 0px 10px;
}

#pdf-canvas {
  display: block;
  border-radius: 4px;
  max-height: calc(100vh - var(--header-h) - var(--footer-h) - 48px);
  max-width: 100%;
  object-fit: contain;
}

/* Page flip animation */
#flip-overlay {
  position: absolute;
  inset: 0;
  z-index: 10;
  pointer-events: none;
  perspective: 1200px;
}

#flip-overlay.hidden {
  display: none;
}

.flip-card {
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  position: relative;
}

.flip-front,
.flip-back {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: 4px;
  overflow: hidden;
}

.flip-front img,
.flip-back canvas {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.flip-back {
  transform: rotateY(180deg);
}

.flip-exit {
  animation: pageFlipExit 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.flip-enter {
  animation: pageFlipEnter 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes pageFlipExit {
  0% {
    transform: perspective(1000px) rotateY(0deg) scale(1);
    opacity: 1;
  }

  50% {
    transform: perspective(1000px) rotateY(-8deg) scale(0.97);
    opacity: 0.6;
  }

  100% {
    transform: perspective(1000px) rotateY(-20deg) scale(0.94);
    opacity: 0;
  }
}

@keyframes pageFlipEnter {
  0% {
    transform: perspective(1000px) rotateY(20deg) scale(0.94);
    opacity: 0;
  }

  50% {
    transform: perspective(1000px) rotateY(8deg) scale(0.97);
    opacity: 0.6;
  }

  100% {
    transform: perspective(1000px) rotateY(0deg) scale(1);
    opacity: 1;
  }
}

@keyframes pageFlipExitBack {
  0% {
    transform: perspective(1000px) rotateY(0deg) scale(1);
    opacity: 1;
  }

  100% {
    transform: perspective(1000px) rotateY(20deg) scale(0.94);
    opacity: 0;
  }
}

@keyframes pageFlipEnterBack {
  0% {
    transform: perspective(1000px) rotateY(-20deg) scale(0.94);
    opacity: 0;
  }

  100% {
    transform: perspective(1000px) rotateY(0deg) scale(1);
    opacity: 1;
  }
}

/* Navigation Buttons */
.nav-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid rgba(0, 0, 0, 0.12);
  color: var(--text);
  font-size: 1rem;
  cursor: pointer;
  z-index: 20;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(8px);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
}

.nav-btn:hover {
  background: var(--accent);
  color: #000;
  transform: translateY(-50%) scale(1.1);
  border-color: var(--accent);
}

.nav-btn:disabled {
  opacity: 0.2;
  cursor: default;
}

.nav-btn:disabled:hover {
  background: rgba(0, 0, 0, 0.5);
  color: var(--text);
  transform: translateY(-50%) scale(1);
}

.prev-btn {
  left: 8px;
}

.next-btn {
  right: 8px;
}

#page-info {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-family: 'Montserrat', sans-serif;
  letter-spacing: 0.05em;
  margin-top: 6px;
}

/* ── Footer ── */
#main-footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--footer-h);
  z-index: 100;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--panel-border);
  box-shadow: 0 -1px 12px rgba(0, 0, 0, 0.07);
  padding: 8px 16px 6px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

#progress-bar-container {
  height: 3px;
  background: rgba(0, 0, 0, 0.10);
  border-radius: 2px;
  overflow: hidden;
}

#progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), #80deea);
  border-radius: 2px;
  transition: width 0.4s ease;
  width: 0%;
}

#sections-nav {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  align-items: center;
  scrollbar-width: none;
}

#sections-nav::-webkit-scrollbar {
  display: none;
}

.sec-tab {
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  cursor: pointer;
  white-space: nowrap;
  background: rgba(0, 0, 0, 0.05);
  border: 1px solid rgba(0, 0, 0, 0.10);
  color: var(--text-muted);
  transition: all 0.3s;
}

.sec-tab:hover {
  background: rgba(0, 0, 0, 0.10);
  color: var(--text);
}

.sec-tab.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
  font-weight: 700;
}

/* ── Section Transition Overlay ── */
#section-transition {
  position: fixed;
  inset: 0;
  z-index: 200;
  background: rgba(240, 244, 248, 0.95);
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(20px);
  transition: opacity 0.4s ease;
}

#section-transition.hidden {
  opacity: 0;
  pointer-events: none;
}

#section-transition.visible {
  opacity: 1;
}

.transition-content {
  text-align: center;
  animation: transitionPop 0.5s ease;
}

@keyframes transitionPop {
  0% {
    transform: scale(0.7) translateY(20px);
    opacity: 0;
  }

  100% {
    transform: scale(1) translateY(0);
    opacity: 1;
  }
}

.transition-emoji {
  font-size: 5rem;
  display: block;
  margin-bottom: 16px;
}

#transition-title {
  font-family: 'Montserrat', sans-serif;
  font-size: 2.5rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
}

/* ── Confetti (poll vote feedback) ── */
.confetti-piece {
  position: fixed;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  z-index: 500;
  pointer-events: none;
  animation: confettiFall 1.2s ease-out forwards;
}

@keyframes confettiFall {
  0% {
    transform: translateY(0) rotate(0deg);
    opacity: 1;
  }

  100% {
    transform: translateY(300px) rotate(720deg);
    opacity: 0;
  }
}

/* ── Loading ── */
#loading-screen {
  position: fixed;
  inset: 0;
  z-index: 300;
  background: #f0f4f8;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  transition: opacity 0.6s ease;
}

#loading-screen.hide {
  opacity: 0;
  pointer-events: none;
}

.loading-logo {
  font-family: 'Montserrat', sans-serif;
  font-size: 3rem;
  font-weight: 900;
  color: #1565C0;
  animation: pulse 1.5s ease infinite;
}

@keyframes pulse {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.4;
  }
}

.loading-text {
  font-size: 0.8rem;
  color: #5f7080;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.loading-bar-outer {
  width: 200px;
  height: 2px;
  background: rgba(0, 0, 0, 0.12);
  border-radius: 1px;
}

.loading-bar-inner {
  height: 100%;
  background: #1565C0;
  border-radius: 1px;
  width: 0%;
  animation: loadProgress 2s ease forwards;
}

@keyframes loadProgress {
  to {
    width: 100%;
  }
}

/* ── Animations ── */
@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@keyframes float {

  0%,
  100% {
    transform: translateY(0px);
  }

  50% {
    transform: translateY(-6px);
  }
}

/* ── Tooltip / hint ── */
.keyboard-hint {
  position: fixed;
  bottom: 82px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.65rem;
  color: var(--text-muted);
  background: rgba(0, 0, 0, 0.6);
  padding: 4px 12px;
  border-radius: 20px;
  animation: fadeIn 0.5s ease 2s both, fadeOut 0.5s ease 6s forwards;
  z-index: 50;
}

@keyframes fadeOut {
  to {
    opacity: 0;
  }
}

/* Scrollbar */
.side-panel::-webkit-scrollbar {
  width: 4px;
}

.side-panel::-webkit-scrollbar-thumb {
  background: var(--panel-border);
  border-radius: 2px;
}

/* Mobile adjustments */
@media (max-width: 900px) {
  :root {
    --panel-w: 220px;
  }
}

@media (max-width: 700px) {
  .side-panel {
    display: none;
  }

  #main-header .audio-controls {
    display: none;
  }
}