/* style.css - Tokyo Neon Street Theme for Katakana Master */

:root {
  /* Color Palette */
  --bg-app: hsl(224, 30%, 7%);
  --bg-card: rgba(17, 24, 39, 0.7);
  --glass-border: rgba(255, 255, 255, 0.05);
  --glass-border-hover: rgba(255, 255, 255, 0.12);
  
  /* Neon Lights HSL values */
  --neon-pink: hsl(325, 95%, 60%);
  --neon-pink-glow: rgba(236, 72, 153, 0.35);
  
  --neon-cyan: hsl(180, 95%, 55%);
  --neon-cyan-glow: rgba(6, 182, 212, 0.35);
  
  --neon-amber: hsl(35, 95%, 55%);
  --neon-amber-glow: rgba(245, 158, 11, 0.35);
  
  --neon-green: hsl(145, 90%, 55%);
  --neon-green-glow: rgba(16, 185, 129, 0.35);
  
  --neon-purple: hsl(270, 90%, 65%);
  --neon-purple-glow: rgba(168, 85, 247, 0.35);

  --text-main: hsl(210, 40%, 98%);
  --text-muted: hsl(215, 20%, 65%);
  --text-dimmed: hsl(215, 15%, 45%);
  
  --font-family: 'Outfit', 'Noto Sans JP', 'Noto Sans KR', sans-serif;
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Global Reset */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: var(--font-family);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg-app);
  color: var(--text-main);
  min-height: 100vh;
  overflow-x: hidden;
  background-image: 
    radial-gradient(circle at 10% 20%, rgba(236, 72, 153, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 90% 80%, rgba(6, 182, 212, 0.08) 0%, transparent 45%);
}

.app-wrapper {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px 40px 20px;
}

/* Header Styling */
.app-header {
  padding: 40px 0 20px 0;
  border-bottom: 1px solid var(--glass-border);
  margin-bottom: 30px;
}

.header-container {
  text-align: center;
  margin-bottom: 24px;
}

.logo {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.logo-neon {
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 6px;
  color: var(--neon-pink);
  text-shadow: 0 0 10px var(--neon-pink);
  animation: neon-pulse-pink 2s infinite alternate;
}

.logo-title {
  font-size: 2.2rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--text-main) 40%, var(--neon-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -1px;
}

.header-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-top: 10px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  font-weight: 300;
}

/* Tabs Navigation */
.app-tabs {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 24px;
}

.tab-btn {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  color: var(--text-muted);
  padding: 12px 20px;
  border-radius: 12px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: var(--transition-smooth);
}

.tab-btn:hover {
  background: rgba(255, 255, 255, 0.04);
  border-color: var(--glass-border-hover);
  color: var(--text-main);
}

.tab-btn.active {
  background: rgba(6, 182, 212, 0.1);
  border-color: var(--neon-cyan);
  color: var(--neon-cyan);
  box-shadow: 0 0 15px var(--neon-cyan-glow);
}

/* Tab Content Visibility */
.tab-content {
  display: none;
  animation: fadeIn 0.4s ease;
}

.tab-content.active {
  display: block;
}

/* Tab 1: Virtual Street Board */
.filter-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
  padding: 14px 20px;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: 16px;
  flex-wrap: wrap;
  gap: 12px;
}

.filter-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

.filter-options {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.filter-btn {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--glass-border);
  color: var(--text-muted);
  padding: 6px 12px;
  border-radius: 8px;
  font-size: 0.8rem;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.filter-btn:hover {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-main);
}

.filter-btn.active {
  background: var(--text-main);
  color: var(--bg-app);
  border-color: var(--text-main);
  font-weight: 600;
}

/* Neon Signboards Grid */
.street-neon-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 24px;
  padding: 10px 0;
}

/* Interactive Signboard Styles */
.neon-sign {
  position: relative;
  min-height: 180px;
  border-radius: 16px;
  background-color: #0b0f19;
  border: 2px solid var(--glass-border);
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  transition: var(--transition-smooth);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  overflow: hidden;
}

.neon-sign:hover {
  transform: translateY(-5px) scale(1.02);
}

/* Neon Sign Variants */
/* 1. Neon Type (Classic Neon Tube) */
.neon-sign.sign-neon {
  border-width: 3px;
}

.neon-sign.sign-neon .sign-text {
  font-size: 2.2rem;
  font-weight: 900;
  text-align: center;
  letter-spacing: 2px;
}

/* 2. Vertical Wood Type (Traditional Restaurant sign) */
.neon-sign.sign-wood {
  background: linear-gradient(135deg, #2b1f1d 0%, #1a1211 100%);
  border: 3px solid #5a3d28;
  writing-mode: vertical-rl;
  text-orientation: upright;
  min-height: 220px;
}

.neon-sign.sign-wood .sign-text {
  font-size: 2rem;
  font-weight: 700;
  color: #fcefdc;
  text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.8);
  letter-spacing: 8px;
}

/* 3. Retro Circle (Logo signs) */
.neon-sign.sign-retro_circle {
  border-radius: 50%;
  aspect-ratio: 1 / 1;
  max-width: 220px;
  margin: 0 auto;
  border: 4px double var(--glass-border);
}

.neon-sign.sign-retro_circle .sign-text {
  font-size: 1.8rem;
  font-weight: 800;
  text-align: center;
}

/* 4. Plastic Box Type (Convenience Store / Drugstore signs) */
.neon-sign.sign-plastic {
  background: #ffffff;
  border: 4px solid #111827;
}

.neon-sign.sign-plastic .sign-text {
  font-size: 1.8rem;
  font-weight: 900;
  color: #111827;
}

/* Dynamic glowing colors */
/* Neon Glow Shadow Animations */
@keyframes neon-pulse-pink {
  0% { text-shadow: 0 0 5px rgba(236, 72, 153, 0.5), 0 0 10px rgba(236, 72, 153, 0.5); }
  100% { text-shadow: 0 0 10px rgba(236, 72, 153, 0.9), 0 0 20px rgba(236, 72, 153, 0.9); }
}
@keyframes neon-pulse-cyan {
  0% { text-shadow: 0 0 5px rgba(6, 182, 212, 0.5), 0 0 10px rgba(6, 182, 212, 0.5); }
  100% { text-shadow: 0 0 10px rgba(6, 182, 212, 0.9), 0 0 20px rgba(6, 182, 212, 0.9); }
}
@keyframes neon-pulse-amber {
  0% { text-shadow: 0 0 5px rgba(245, 158, 11, 0.5), 0 0 10px rgba(245, 158, 11, 0.5); }
  100% { text-shadow: 0 0 10px rgba(245, 158, 11, 0.9), 0 0 20px rgba(245, 158, 11, 0.9); }
}
@keyframes neon-pulse-green {
  0% { text-shadow: 0 0 5px rgba(16, 185, 129, 0.5), 0 0 10px rgba(16, 185, 129, 0.5); }
  100% { text-shadow: 0 0 10px rgba(16, 185, 129, 0.9), 0 0 20px rgba(16, 185, 129, 0.9); }
}
@keyframes neon-pulse-purple {
  0% { text-shadow: 0 0 5px rgba(168, 85, 247, 0.5), 0 0 10px rgba(168, 85, 247, 0.5); }
  100% { text-shadow: 0 0 10px rgba(168, 85, 247, 0.9), 0 0 20px rgba(168, 85, 247, 0.9); }
}

.sign-cat-badge {
  position: absolute;
  top: 10px;
  right: 12px;
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 2px 8px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-muted);
}

.sign-wood .sign-cat-badge {
  writing-mode: horizontal-tb;
  top: 10px;
  right: auto;
  left: 10px;
}

/* Tab 2: Flashcards Styling */
.flashcards-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  padding: 20px 0;
}

.flashcard-deck-controls {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--neon-cyan);
}

.flashcard-container {
  perspective: 1000px;
  width: 340px;
  height: 460px;
}

.flashcard {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
}

.flashcard.flipped {
  transform: rotateY(180deg);
}

.card-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 24px;
  border: 2px solid var(--glass-border);
  padding: 30px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
}

.card-front {
  background: linear-gradient(135deg, hsl(222, 25%, 12%) 0%, hsl(222, 25%, 8%) 100%);
  border-color: rgba(255, 255, 255, 0.08);
}

.card-back {
  background: linear-gradient(135deg, hsl(222, 25%, 8%) 0%, hsl(222, 25%, 15%) 100%);
  border-color: var(--neon-cyan);
  transform: rotateY(180deg);
}

.card-cat-tag {
  align-self: flex-start;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-muted);
}

.card-big-text {
  font-size: 3.2rem;
  font-weight: 900;
  letter-spacing: 2px;
  color: var(--text-main);
  text-shadow: 0 0 15px rgba(255, 255, 255, 0.2);
  text-align: center;
}

.card-hint-prompt {
  font-size: 0.8rem;
  color: var(--text-dimmed);
}

.card-back-mean {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--neon-cyan);
  text-shadow: 0 0 10px var(--neon-cyan-glow);
  text-align: center;
}

.card-back-read {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-main);
  margin-top: -10px;
}

.card-back-romaji {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-family: monospace;
}

.card-back-tip {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
  text-align: center;
  border-top: 1px solid var(--glass-border);
  padding-top: 14px;
}

.deck-navigation {
  display: flex;
  gap: 16px;
  margin-top: 10px;
}

.btn-nav {
  min-width: 130px;
}

/* Tab 3: Katakana 50-Sound Chart */
.chart-header-info {
  background: rgba(6, 182, 212, 0.06);
  border: 1px solid rgba(6, 182, 212, 0.15);
  border-radius: 12px;
  padding: 12px 18px;
  font-size: 0.85rem;
  color: var(--neon-cyan);
  margin-bottom: 20px;
  display: flex;
  justify-content: center;
}

.katakana-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px;
  max-width: 700px;
  margin: 0 auto;
}

.letter-box {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  padding: 14px 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.letter-box:hover {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--neon-pink);
  transform: translateY(-2px);
  box-shadow: 0 0 10px var(--neon-pink-glow);
}

.letter-box:active {
  transform: translateY(0);
}

.letter-box.empty {
  visibility: hidden;
}

.letter-char {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 2px;
}

.letter-romaji {
  font-size: 0.75rem;
  color: var(--text-dimmed);
  text-transform: uppercase;
}

/* Tab 4: Quiz Section */
.quiz-container {
  max-width: 550px;
  margin: 20px auto;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  padding: 40px 30px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
}

.quiz-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  animation: fadeIn 0.3s ease;
}

.quiz-intro-icon {
  font-size: 4rem;
  margin-bottom: 16px;
}

.quiz-container h2 {
  font-size: 1.6rem;
  font-weight: 800;
  margin-bottom: 10px;
}

.quiz-container p {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 24px;
}

.quiz-header-status {
  display: flex;
  justify-content: space-between;
  width: 100%;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 24px;
  border-bottom: 1px solid var(--glass-border);
  padding-bottom: 12px;
}

.quiz-question-container {
  width: 100%;
  margin-bottom: 30px;
}

.quiz-card-sign {
  width: 100%;
  min-height: 160px;
  background-color: #0b0f19;
  border: 3px solid var(--neon-pink);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 20px var(--neon-pink-glow);
}

.quiz-sign-text {
  font-size: 2.6rem;
  font-weight: 900;
  color: var(--text-main);
  text-shadow: 0 0 10px var(--neon-pink);
  letter-spacing: 2px;
}

.quiz-options-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  width: 100%;
}

.quiz-option-btn {
  width: 100%;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--glass-border);
  color: var(--text-main);
  padding: 16px 20px;
  border-radius: 12px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
  text-align: left;
}

.quiz-option-btn:hover {
  background: rgba(255, 255, 255, 0.07);
  border-color: var(--glass-border-hover);
}

.quiz-option-btn.correct {
  background: rgba(16, 185, 129, 0.15) !important;
  border-color: var(--neon-green) !important;
  color: var(--neon-green) !important;
  box-shadow: 0 0 10px var(--neon-green-glow);
}

.quiz-option-btn.incorrect {
  background: rgba(239, 68, 68, 0.15) !important;
  border-color: hsl(0, 84%, 60%) !important;
  color: hsl(0, 84%, 60%) !important;
  box-shadow: 0 0 10px rgba(239, 68, 68, 0.25);
}

.quiz-result-icon {
  font-size: 4rem;
  margin-bottom: 12px;
  animation: float 2.5s infinite ease-in-out;
}

.quiz-final-score-box {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--glass-border);
  border-radius: 16px;
  padding: 16px 30px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  margin-bottom: 20px;
}

.quiz-final-score-box .label {
  font-size: 0.8rem;
  color: var(--text-dimmed);
  text-transform: uppercase;
}

.quiz-final-score-box .score {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--neon-cyan);
  text-shadow: 0 0 10px var(--neon-cyan-glow);
}

.quiz-result-actions {
  display: flex;
  gap: 12px;
  width: 100%;
}

.quiz-result-actions .btn {
  flex: 1;
}

/* Modals */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  animation: fadeIn 0.25s ease;
}

.modal-content.word-modal {
  width: 90%;
  max-width: 460px;
  background: hsl(222, 25%, 8%);
  border: 2px solid var(--neon-cyan);
  border-radius: 24px;
  box-shadow: 0 0 25px var(--neon-cyan-glow);
  animation: scaleUp 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.modal-header {
  padding: 20px 24px 10px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-category-badge {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 6px;
  background: rgba(6, 182, 212, 0.15);
  color: var(--neon-cyan);
  border: 1px solid rgba(6, 182, 212, 0.3);
}

.modal-body {
  padding: 10px 24px 24px 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.modal-word-display {
  text-align: center;
  padding: 20px 0;
  border-bottom: 1px solid var(--glass-border);
}

.modal-katakana {
  font-size: 3rem;
  font-weight: 900;
  letter-spacing: 2px;
  color: var(--text-main);
  text-shadow: 0 0 10px rgba(255, 255, 255, 0.15);
}

.modal-romaji-read {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-top: 8px;
}

.modal-romaji-read .romaji {
  font-size: 1rem;
  color: var(--text-muted);
  font-family: monospace;
}

.modal-romaji-read .read {
  font-size: 1rem;
  color: var(--neon-pink);
  font-weight: 600;
}

.modal-translation-section h3, 
.modal-tip-section h3 {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-dimmed);
  text-transform: uppercase;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 4px;
}

.modal-translation-section .translation {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-main);
}

.modal-tip-section .tip-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--glass-border);
  display: flex;
  gap: 12px;
  justify-content: flex-end;
}

/* Button UI Components */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: var(--transition-smooth);
  border: none;
}

.btn-lg {
  padding: 16px 32px;
  font-size: 1rem;
}

.btn-primary {
  background: var(--neon-cyan);
  color: var(--bg-app);
}

.btn-primary:hover {
  background: hsl(180, 95%, 45%);
  box-shadow: 0 0 15px var(--neon-cyan-glow);
  transform: translateY(-2px);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-main);
  border: 1px solid var(--glass-border);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--glass-border-hover);
}

.btn-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: 8px;
  transition: var(--transition-smooth);
}

.btn-icon:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
}

/* Voice speaking indicator bar */
.voice-status-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100vw;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 24px;
  background: rgba(6, 182, 212, 0.1);
  border-top: 1px solid rgba(6, 182, 212, 0.2);
  font-size: 0.8rem;
  color: var(--neon-cyan);
  z-index: 1000;
  animation: slideUp 0.3s ease;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--neon-cyan);
}

.pulsing {
  animation: pulse 1.5s infinite;
}

/* Animations */
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-6px); }
}

@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(6, 182, 212, 0.7); }
  70% { box-shadow: 0 0 0 10px rgba(6, 182, 212, 0); }
  100% { box-shadow: 0 0 0 0 rgba(6, 182, 212, 0); }
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes scaleUp {
  from { transform: scale(0.95); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

@keyframes slideUp {
  from { transform: translateY(100%); }
  to { transform: translateY(0); }
}

/* Modal Image and Fallback Icon styling */
.modal-image-container {
  width: 100%;
  height: 180px;
  border-radius: 16px;
  overflow: hidden;
  background: #090d16;
  border: 1px solid var(--glass-border);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  position: relative;
}

#modal-word-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  border-radius: 14px;
}

.modal-fallback-icon {
  font-size: 4rem;
  filter: drop-shadow(0 0 10px rgba(6, 182, 212, 0.4));
  animation: float 3s ease-in-out infinite;
}

.sign-icon-display {
  font-size: 2.2rem;
  margin-bottom: 10px;
  filter: drop-shadow(0 0 5px rgba(255, 255, 255, 0.15));
  transition: var(--transition-smooth);
}

.sign-wood .sign-icon-display {
  writing-mode: horizontal-tb;
  margin-bottom: 0;
  margin-left: 12px;
  font-size: 1.8rem;
}

.sign-retro_circle .sign-icon-display {
  font-size: 2.2rem;
}

/* Responsive grid settings */
@media (max-width: 768px) {
  .logo-title {
    font-size: 1.8rem;
  }
  
  .tab-btn {
    padding: 10px 14px;
    font-size: 0.85rem;
  }
  
  .street-neon-container {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
  }
  
  .neon-sign {
    min-height: 150px;
    padding: 12px;
  }
  
  .neon-sign.sign-neon .sign-text {
    font-size: 1.7rem;
  }
  
  .neon-sign.sign-wood {
    min-height: 180px;
  }
  
  .neon-sign.sign-wood .sign-text {
    font-size: 1.6rem;
    letter-spacing: 5px;
  }
  
  .neon-sign.sign-retro_circle .sign-text {
    font-size: 1.4rem;
  }
  
  .flashcard-container {
    width: 290px;
    height: 400px;
  }
  
  .card-big-text {
    font-size: 2.6rem;
  }
  
  .katakana-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
  }
  
  .letter-char {
    font-size: 1.4rem;
  }
  
  .quiz-container {
    padding: 24px 16px;
  }
  
  .quiz-sign-text {
    font-size: 2rem;
  }
}