/* ============================================
   VARIABLES & BASE STYLES
   ============================================ */
:root {
  --color-primary: #e84a7f;
  --color-primary-light: #ff6b9d;
  --color-primary-dark: #c44569;
  --color-secondary: #ffeef3;
  --color-background: #fff5f7;
  --color-text: #4a2c3d;
  --color-text-muted: #8b6b7a;
  --color-white: #ffffff;
  --color-accent: #ffb8c9;
  
  --font-display: 'Playfair Display', Georgia, serif;
  --font-body: 'Lora', Georgia, serif;
  
  --shadow-soft: 0 4px 20px rgba(232, 74, 127, 0.15);
  --shadow-medium: 0 8px 30px rgba(232, 74, 127, 0.2);
  --shadow-large: 0 20px 60px rgba(232, 74, 127, 0.25);
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 32px;
  
  --transition-fast: 0.2s ease;
  --transition-medium: 0.3s ease;
  --transition-slow: 0.5s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background: var(--color-background);
  color: var(--color-text);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
}

/* ============================================
   FLOATING HEARTS BACKGROUND
   ============================================ */
.floating-hearts {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.floating-heart {
  position: absolute;
  bottom: -50px;
  animation: floatUp linear infinite;
  opacity: 0;
}

@keyframes floatUp {
  0% {
    transform: translateY(0) rotate(0deg) scale(1);
    opacity: 0;
  }
  10% {
    opacity: 0.7;
  }
  90% {
    opacity: 0.7;
  }
  100% {
    transform: translateY(-110vh) rotate(360deg) scale(0.5);
    opacity: 0;
  }
}

/* ============================================
   SCREENS
   ============================================ */
.screen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-slow), visibility var(--transition-slow);
  z-index: 1;
}

.screen.active {
  opacity: 1;
  visibility: visible;
}

/* ============================================
   WELCOME SCREEN
   ============================================ */
.welcome-content {
  text-align: center;
  padding: 2rem;
  animation: fadeInUp 0.8s ease;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.welcome-content .heart-icon {
  width: 100px;
  height: 100px;
  margin: 0 auto 2rem;
  color: var(--color-primary);
}

.welcome-content .heart-icon.pulse {
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
}

.welcome-content h1 {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 8vw, 4rem);
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 1rem;
}

.welcome-content p {
  font-size: 1.25rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.welcome-content .hint-text {
  font-size: 1rem;
  font-style: italic;
  margin-bottom: 2rem;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 1rem 2rem;
  border: none;
  border-radius: var(--radius-lg);
  font-family: var(--font-body);
  font-size: 1.1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-medium);
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary-dark));
  color: var(--color-white);
  box-shadow: var(--shadow-medium);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-large);
}

.btn-primary:active {
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--color-white);
  color: var(--color-primary);
  box-shadow: var(--shadow-soft);
}

.btn-secondary:hover {
  background: var(--color-secondary);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: var(--color-white);
}

.btn-large {
  padding: 1.25rem 2.5rem;
  font-size: 1.25rem;
}

.btn .arrow-icon {
  width: 20px;
  height: 20px;
  transition: transform var(--transition-fast);
}

.btn:hover .arrow-icon {
  transform: translateX(5px);
}

.btn-icon {
  width: 20px;
  height: 20px;
}

.heart-icon-small {
  width: 20px;
  height: 20px;
}

/* ============================================
   PUZZLE SCREEN
   ============================================ */
.puzzle-container {
  width: 100%;
  max-width: 500px;
  padding: 1.5rem;
  animation: fadeInUp 0.8s ease;
}

.puzzle-header {
  text-align: center;
  margin-bottom: 1.5rem;
}

.puzzle-header h2 {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  color: var(--color-primary-dark);
  margin-bottom: 0.5rem;
}

.puzzle-header p {
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--color-secondary);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 0.5rem;
}

.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--color-primary-light), var(--color-primary-dark));
  border-radius: 4px;
  transition: width var(--transition-medium);
}

.progress-text {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.puzzle-wrapper {
  position: relative;
  margin-bottom: 1.5rem;
}

.puzzle-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  background: var(--color-white);
  padding: 12px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-medium);
}

.puzzle-piece {
  aspect-ratio: 1;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
  background: var(--color-secondary);
}

.puzzle-piece:hover {
  transform: scale(1.05);
  z-index: 2;
}

.puzzle-piece.selected {
  box-shadow: 0 0 0 3px var(--color-primary), var(--shadow-medium);
  transform: scale(1.08);
  z-index: 3;
}

.puzzle-piece.correct {
  box-shadow: 0 0 0 2px #4ade80;
}

.puzzle-piece svg {
  width: 100%;
  height: 100%;
  display: block;
}

.puzzle-piece.dragging {
  opacity: 0.8;
  transform: scale(1.1);
  z-index: 10;
}

.puzzle-piece.drag-over {
  background: var(--color-accent);
}

/* Hint Overlay */
.hint-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(255, 255, 255, 0.95);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-lg);
  transition: opacity var(--transition-medium);
  z-index: 5;
}

.hint-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.hint-heart {
  width: 80%;
  max-width: 200px;
  animation: hintPulse 1s ease-in-out infinite;
}

@keyframes hintPulse {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
}

.puzzle-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================================
   COMPLETION SCREEN
   ============================================ */
.completion-overlay {
  position: relative;
  text-align: center;
  padding: 2rem;
}

.sparkles {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 300px;
  height: 300px;
  pointer-events: none;
}

.sparkle {
  position: absolute;
  font-size: 1.5rem;
  animation: sparkleFloat 2s ease-in-out infinite;
}

@keyframes sparkleFloat {
  0%, 100% {
    opacity: 0;
    transform: scale(0) rotate(0deg);
  }
  50% {
    opacity: 1;
    transform: scale(1) rotate(180deg);
  }
}

.completion-content {
  position: relative;
  z-index: 1;
  animation: fadeInUp 0.8s ease;
}

.completion-heart {
  width: 120px;
  height: 120px;
  margin: 0 auto 1.5rem;
  animation: completionBounce 0.6s ease;
}

@keyframes completionBounce {
  0% {
    transform: scale(0);
  }
  50% {
    transform: scale(1.2);
  }
  100% {
    transform: scale(1);
  }
}

.completion-content h2 {
  font-family: var(--font-display);
  font-size: 2.5rem;
  color: var(--color-primary-dark);
  margin-bottom: 0.5rem;
}

.completion-content p {
  color: var(--color-text-muted);
  font-size: 1.2rem;
  margin-bottom: 2rem;
}

/* ============================================
   LETTER SCREEN
   ============================================ */
.letter-container {
  position: relative;
  width: 100%;
  max-width: 700px;
  padding: 1rem;
  animation: letterReveal 1s ease;
}

@keyframes letterReveal {
  from {
    opacity: 0;
    transform: scale(0.9) translateY(20px);
  }
  to {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}

.letter-decoration {
  position: absolute;
  width: 60px;
  height: 60px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%23ffb8c9'%3E%3Cpath d='M12 21.35l-1.45-1.32C5.4 15.36 2 12.28 2 8.5 2 5.42 4.42 3 7.5 3c1.74 0 3.41.81 4.5 2.09C13.09 3.81 14.76 3 16.5 3 19.58 3 22 5.42 22 8.5c0 3.78-3.4 6.86-8.55 11.54L12 21.35z'/%3E%3C/svg%3E") no-repeat center;
  background-size: contain;
  opacity: 0.5;
}

.letter-decoration.top-left {
  top: -20px;
  left: -10px;
  transform: rotate(-15deg);
}

.letter-decoration.top-right {
  top: -20px;
  right: -10px;
  transform: rotate(15deg);
}

.letter-decoration.bottom-left {
  bottom: -20px;
  left: -10px;
  transform: rotate(15deg);
}

.letter-decoration.bottom-right {
  bottom: -20px;
  right: -10px;
  transform: rotate(-15deg);
}

.letter {
  background: var(--color-white);
  border-radius: var(--radius-xl);
  padding: 2.5rem;
  box-shadow: var(--shadow-large);
  position: relative;
  overflow: hidden;
}

.letter::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 6px;
  background: linear-gradient(90deg, var(--color-primary-light), var(--color-primary-dark), var(--color-primary-light));
}

.letter-header {
  text-align: center;
  margin-bottom: 2rem;
}

.letter-hearts {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.heart-deco {
  color: var(--color-primary);
  font-size: 1.5rem;
  animation: heartBeat 1.5s ease-in-out infinite;
}

.heart-deco:nth-child(2) {
  animation-delay: 0.2s;
}

.heart-deco:nth-child(3) {
  animation-delay: 0.4s;
}

@keyframes heartBeat {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.2);
  }
}

.letter-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3rem);
  font-weight: 700;
  color: var(--color-primary-dark);
}

.letter-body {
  font-size: 1.1rem;
  line-height: 1.8;
  color: var(--color-text);
}

.letter-body p {
  margin-bottom: 1.5rem;
  text-align: justify;
}

.letter-body .highlight {
  font-style: italic;
  color: var(--color-primary-dark);
  font-weight: 500;
  text-align: center;
  font-size: 1.2rem;
  padding: 1rem;
  background: var(--color-secondary);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-primary);
}

.letter-body .closing {
  text-align: right;
  font-weight: 600;
  color: var(--color-primary-dark);
  margin-top: 2rem;
}

.letter-footer {
  margin-top: 2rem;
  text-align: center;
}

.signature {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.signature p {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-style: italic;
  color: var(--color-primary);
}

.heart-signature {
  width: 50px;
  height: 50px;
  color: var(--color-primary);
  animation: pulse 2s ease-in-out infinite;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 600px) {
  .puzzle-container {
    padding: 1rem;
  }

  .puzzle-grid {
    gap: 6px;
    padding: 10px;
  }

  .letter {
    padding: 1.5rem;
    border-radius: var(--radius-lg);
  }

  .letter-body {
    font-size: 1rem;
  }

  .btn {
    padding: 0.875rem 1.5rem;
    font-size: 1rem;
  }

  .puzzle-actions {
    gap: 0.75rem;
  }

  .letter-decoration {
    width: 40px;
    height: 40px;
  }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}