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

:root {
  --blue: #2563EB;
  --blue-dark: #1d4ed8;
  --blue-light: #dbeafe;
  --teal: #0d9488;
  --teal-light: #ccfbf1;
  --red: #dc2626;
  --red-light: #fee2e2;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --white: #ffffff;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Space Mono", "SF Mono", "Cascadia Code", "Fira Code", Consolas, "Courier New", monospace;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--white);
  color: var(--gray-800);
  line-height: 1.5;
  min-height: 100dvh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ===== App Shell ===== */
#app {
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
  min-height: 100dvh;
  position: relative;
}

.screen {
  display: none;
  min-height: 100dvh;
}

.screen.active {
  display: flex;
  flex-direction: column;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: none;
  border-radius: 12px;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s ease, background-color 0.2s ease, opacity 0.2s ease;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--blue);
  color: var(--white);
  padding: 16px 32px;
}

.btn-primary:active {
  background: var(--blue-dark);
}

.btn-outline {
  background: var(--white);
  color: var(--gray-700);
  border: 1.5px solid var(--gray-200);
  padding: 14px 24px;
}

.btn-outline:active {
  background: var(--gray-50);
}

.btn-text {
  background: none;
  color: var(--gray-400);
  font-size: 0.875rem;
  font-weight: 500;
  padding: 12px 24px;
}

.btn-large {
  width: 100%;
  padding: 18px 32px;
  font-size: 1.125rem;
  border-radius: 14px;
}

/* ===== Landing Screen ===== */
.landing-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 40px 24px;
  text-align: center;
}

.landing-icon {
  margin-bottom: 24px;
  opacity: 0;
  animation: fadeInDown 0.6s ease forwards;
}

.landing-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--gray-900);
  line-height: 1.2;
  margin-bottom: 8px;
  opacity: 0;
  animation: fadeInDown 0.6s ease 0.1s forwards;
}

.landing-subtitle {
  font-size: 1rem;
  color: var(--gray-500);
  margin-bottom: 16px;
  opacity: 0;
  animation: fadeInDown 0.6s ease 0.2s forwards;
}

.landing-badge {
  display: inline-block;
  background: var(--blue-light);
  color: var(--blue);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 6px 16px;
  border-radius: 100px;
  margin-bottom: 40px;
  opacity: 0;
  animation: fadeInDown 0.6s ease 0.3s forwards;
}

#start-btn {
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.5s forwards;
}

.landing-disclaimer {
  font-size: 0.75rem;
  color: var(--gray-400);
  margin-top: 24px;
  line-height: 1.6;
  opacity: 0;
  animation: fadeIn 0.6s ease 0.7s forwards;
}

/* ===== Quiz Screen ===== */
.quiz-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--white);
  border-bottom: 1px solid var(--gray-100);
  padding: 16px 24px 0;
}

.le-display {
  text-align: center;
  padding-bottom: 12px;
}

.le-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--gray-400);
  margin-bottom: 4px;
}

.le-number-wrap {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 6px;
}

.le-number {
  font-family: var(--font-mono);
  font-size: 3rem;
  font-weight: 800;
  line-height: 1;
  color: var(--gray-900);
  transition: color 0.4s ease;
  min-width: 2.5ch;
  text-align: center;
}

.le-number.positive {
  color: var(--teal);
}

.le-number.negative {
  color: var(--red);
}

.le-unit {
  font-size: 1rem;
  font-weight: 500;
  color: var(--gray-400);
}

.progress-bar {
  height: 3px;
  background: var(--gray-100);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 4px;
}

.progress-fill {
  height: 100%;
  background: var(--blue);
  border-radius: 3px;
  width: 0%;
  transition: width 0.4s ease;
}

.question-counter {
  text-align: center;
  padding: 8px 0;
  font-size: 0.8rem;
  color: var(--gray-400);
  font-weight: 500;
}

/* ===== Question Area ===== */
.quiz-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 24px 24px 40px;
  overflow: hidden;
}

.question-container {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.question-container.entering {
  animation: slideInRight 0.35s ease forwards;
}

.question-container.exiting {
  animation: slideOutLeft 0.3s ease forwards;
}

.question-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--gray-900);
  line-height: 1.4;
  margin-bottom: 24px;
}

.answers-container {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.answer-btn {
  display: flex;
  align-items: center;
  width: 100%;
  min-height: 56px;
  padding: 16px 20px;
  background: var(--white);
  border: 1.5px solid var(--gray-200);
  border-radius: 14px;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 500;
  color: var(--gray-700);
  text-align: left;
  cursor: pointer;
  transition: transform 0.12s ease, border-color 0.2s ease, background-color 0.2s ease;
  -webkit-tap-highlight-color: transparent;
}

.answer-btn:active {
  transform: scale(0.98);
  border-color: var(--blue);
  background: var(--blue-light);
}

.answer-btn.selected {
  border-color: var(--blue);
  background: var(--blue-light);
  color: var(--blue-dark);
  font-weight: 600;
}

/* ===== Result Screen ===== */
.result-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 40px 24px;
  text-align: center;
}

.result-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--gray-400);
  margin-bottom: 8px;
  opacity: 0;
  animation: fadeIn 0.5s ease 0.2s forwards;
}

.result-number-wrap {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 8px;
  margin-bottom: 16px;
  opacity: 0;
  animation: scaleIn 0.6s cubic-bezier(0.34, 1.56, 0.64, 1) 0.4s forwards;
}

.result-number {
  font-family: var(--font-mono);
  font-size: 5rem;
  font-weight: 800;
  line-height: 1;
  color: var(--gray-900);
}

.result-unit {
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--gray-400);
}

/* ===== Share Card (hidden, used for screenshot) ===== */
.share-card {
  position: absolute;
  left: -9999px;
  top: -9999px;
  width: 400px;
  pointer-events: none;
}

.share-card-inner {
  background: linear-gradient(135deg, #f0f5ff 0%, #ffffff 50%, #f0fdf4 100%);
  border: 2px solid var(--gray-200);
  border-radius: 20px;
  padding: 40px 32px;
  text-align: center;
}

.share-card-icon {
  margin-bottom: 12px;
}

.share-card-title {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--gray-400);
  margin-bottom: 8px;
}

.share-card-number {
  font-family: var(--font-mono);
  font-size: 5rem;
  font-weight: 800;
  line-height: 1;
  color: var(--gray-900);
  margin-bottom: 4px;
}

.share-card-unit {
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--gray-400);
  margin-bottom: 16px;
}

.share-card-url {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--gray-300);
  letter-spacing: 0.03em;
}

/* ===== Share Buttons ===== */
.share-buttons {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 100%;
  max-width: 320px;
  opacity: 0;
  animation: fadeInUp 0.5s ease 1s forwards;
}

.btn-share {
  width: 100%;
}

#btn-retake {
  margin-top: 8px;
  opacity: 0;
  animation: fadeIn 0.5s ease 1.2s forwards;
}

/* Toast notification */
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--gray-800);
  color: var(--white);
  padding: 12px 24px;
  border-radius: 10px;
  font-size: 0.875rem;
  font-weight: 500;
  opacity: 0;
  transition: opacity 0.3s ease, transform 0.3s ease;
  z-index: 100;
  pointer-events: none;
}

.toast.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ===== Animations ===== */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.5);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(40px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideOutLeft {
  from {
    opacity: 1;
    transform: translateX(0);
  }
  to {
    opacity: 0;
    transform: translateX(-40px);
  }
}

/* ===== Responsive ===== */
@media (max-width: 380px) {
  .landing-title {
    font-size: 1.75rem;
  }

  .le-number {
    font-size: 2.5rem;
  }

  .result-number {
    font-size: 4rem;
  }

  .question-text {
    font-size: 1.125rem;
  }
}

@media (min-width: 481px) {
  #app {
    border-left: 1px solid var(--gray-100);
    border-right: 1px solid var(--gray-100);
  }
}