/* ==========================================================================
   Glowing Heart - Visual Styles & Motion Design
   ========================================================================== */

:root {
  --bg-color: #0f0000;
  --bg-gradient: radial-gradient(circle at 50% 50%, #220306 0%, #110002 60%, #080001 100%);
  --crimson-glow: rgba(255, 30, 50, 0.45);
  --crimson-bright: #ff1a3c;
  --crimson-border: rgba(255, 60, 80, 0.25);
  --glass-surface: rgba(24, 4, 8, 0.72);
  --glass-surface-hover: rgba(48, 10, 16, 0.88);
  --text-main: #fde8ea;
  --text-muted: #d99a9f;
  --font-serif: "Playfair Display", "Cinzel", "Georgia", serif;
  --font-sans: "Plus Jakarta Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-full: 9999px;
  --trans-fast: 0.18s ease;
  --trans-smooth: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: var(--bg-color);
  background-image: var(--bg-gradient);
  color: var(--text-main);
  font-family: var(--font-sans);
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
}

/* Background Atmospheric Stars Dust */
.stars-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    radial-gradient(1px 1px at 20px 30px, rgba(255, 180, 190, 0.6), rgba(0,0,0,0)),
    radial-gradient(1px 1px at 90px 140px, rgba(255, 100, 120, 0.4), rgba(0,0,0,0)),
    radial-gradient(1.5px 1.5px at 200px 70px, rgba(255, 220, 230, 0.5), rgba(0,0,0,0)),
    radial-gradient(1px 1px at 320px 220px, rgba(255, 150, 170, 0.3), rgba(0,0,0,0)),
    radial-gradient(1.5px 1.5px at 450px 310px, rgba(255, 120, 140, 0.5), rgba(0,0,0,0)),
    radial-gradient(1px 1px at 600px 180px, rgba(255, 200, 210, 0.4), rgba(0,0,0,0));
  background-repeat: repeat;
  background-size: 550px 550px;
  opacity: 0.7;
  z-index: 1;
}

/* Main Canvas */
#heartCanvas {
  display: block;
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 2;
  cursor: pointer;
}

/* Interaction Burst Overlay */
.interaction-overlay {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 3;
  overflow: hidden;
}

.burst-heart {
  position: absolute;
  pointer-events: none;
  transform: translate(-50%, -50%);
  animation: burstFloat 1.2s cubic-bezier(0.12, 0.8, 0.32, 1) forwards;
  color: #ff3355;
  font-size: 1.25rem;
  text-shadow: 0 0 10px rgba(255, 50, 80, 0.8);
  will-change: transform, opacity;
}

@keyframes burstFloat {
  0% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(0.6) rotate(0deg);
  }
  60% {
    opacity: 0.9;
  }
  100% {
    opacity: 0;
    transform: translate(calc(-50% + var(--dx)), calc(-50% + var(--dy))) scale(1.3) rotate(var(--rot));
  }
}

/* Top Navigation Bar */
.top-nav {
  position: absolute;
  top: 1rem;
  left: 1rem;
  right: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  z-index: 10;
  pointer-events: none;
  transition: opacity var(--trans-smooth), transform var(--trans-smooth);
}

.top-nav.dimmed {
  opacity: 0.25;
  transform: translateY(-4px);
}

.top-nav:hover,
.top-nav:focus-within {
  opacity: 1;
  transform: translateY(0);
}

.brand {
  pointer-events: auto;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.85rem;
  background: var(--glass-surface);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--crimson-border);
  border-radius: var(--radius-full);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.heart-pulse-icon {
  color: var(--crimson-bright);
  font-size: 1.1rem;
  display: inline-block;
  animation: pulseScale 1.8s infinite ease-in-out;
}

@keyframes pulseScale {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.22); }
}

.brand-text {
  font-family: var(--font-serif);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: #fff;
  text-shadow: 0 0 8px rgba(255, 60, 80, 0.6);
}

/* Action Buttons Bar */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  pointer-events: auto;
}

.ctrl-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 44px;
  min-width: 44px;
  padding: 0.5rem 0.85rem;
  background: var(--glass-surface);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--crimson-border);
  border-radius: var(--radius-full);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 0.825rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--trans-fast);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.35);
}

.ctrl-btn:hover {
  background: var(--glass-surface-hover);
  border-color: rgba(255, 90, 110, 0.5);
  box-shadow: 0 0 16px var(--crimson-glow);
  transform: translateY(-1px);
}

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

.ctrl-btn:focus-visible {
  outline: 2px solid #ff4d6d;
  outline-offset: 2px;
}

.ctrl-btn.active {
  background: rgba(180, 10, 30, 0.6);
  border-color: #ff3355;
  box-shadow: 0 0 14px rgba(255, 40, 70, 0.7);
}

.ctrl-btn.icon-only {
  padding: 0;
  width: 44px;
  height: 44px;
}

.ctrl-btn .icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.hidden {
  display: none !important;
}

/* Touch Hint */
.touch-hint {
  position: absolute;
  bottom: 1.25rem;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(15, 0, 3, 0.7);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 50, 70, 0.15);
  border-radius: var(--radius-full);
  padding: 0.4rem 1.1rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  pointer-events: none;
  z-index: 10;
  text-align: center;
  white-space: nowrap;
  animation: fadeInHint 1s ease 2s both, fadeOutHint 1s ease 12s forwards;
}

@keyframes fadeInHint {
  from { opacity: 0; transform: translate(-50%, 8px); }
  to { opacity: 1; transform: translate(-50%, 0); }
}

@keyframes fadeOutHint {
  to { opacity: 0; pointer-events: none; }
}

/* Modal Dialog */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem;
  z-index: 100;
  animation: fadeInBackdrop 0.22s ease-out;
}

@keyframes fadeInBackdrop {
  from { opacity: 0; }
  to { opacity: 1; }
}

.modal-card {
  width: 100%;
  max-width: 460px;
  background: #190306;
  border: 1px solid rgba(255, 60, 80, 0.35);
  border-radius: var(--radius-md);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.8), 0 0 25px rgba(255, 20, 40, 0.2);
  padding: 1.5rem;
  color: var(--text-main);
  animation: zoomModal 0.24s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes zoomModal {
  from { transform: scale(0.94); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid rgba(255, 50, 70, 0.2);
}

.modal-header h2 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
  text-shadow: 0 0 8px rgba(255, 50, 80, 0.5);
}

.close-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.75rem;
  line-height: 1;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color var(--trans-fast);
}

.close-btn:hover {
  color: #fff;
}

.close-btn:focus-visible {
  outline: 2px solid #ff4d6d;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
}

.form-group label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-main);
}

.form-group input {
  min-height: 46px;
  padding: 0.6rem 0.9rem;
  background: rgba(10, 0, 2, 0.8);
  border: 1px solid rgba(255, 70, 90, 0.3);
  border-radius: var(--radius-sm);
  color: #fff;
  font-family: var(--font-serif);
  font-size: 1.05rem;
  transition: border-color var(--trans-fast), box-shadow var(--trans-fast);
}

.form-group input:focus {
  outline: none;
  border-color: #ff2d55;
  box-shadow: 0 0 12px rgba(255, 45, 85, 0.4);
}

.field-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.quick-presets {
  margin-bottom: 1.5rem;
}

.presets-label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.presets-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.preset-chip {
  background: rgba(45, 8, 12, 0.8);
  border: 1px solid rgba(255, 60, 80, 0.25);
  border-radius: var(--radius-full);
  color: #ffccd3;
  padding: 0.35rem 0.7rem;
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--trans-fast);
}

.preset-chip:hover {
  background: rgba(90, 15, 25, 0.9);
  border-color: rgba(255, 80, 100, 0.5);
  color: #fff;
}

.modal-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.btn-primary, .btn-secondary {
  min-height: 44px;
  padding: 0.6rem 1.15rem;
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--trans-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.btn-primary {
  background: linear-gradient(135deg, #ff1a3c 0%, #b8051e 100%);
  border: 1px solid rgba(255, 120, 140, 0.4);
  color: #fff;
  box-shadow: 0 4px 14px rgba(255, 26, 60, 0.4);
}

.btn-primary:hover {
  box-shadow: 0 0 20px rgba(255, 40, 75, 0.7);
  transform: translateY(-1px);
}

.btn-secondary {
  background: rgba(35, 5, 10, 0.85);
  border: 1px solid rgba(255, 60, 80, 0.25);
  color: #ffd6dc;
}

.btn-secondary:hover {
  background: rgba(60, 10, 18, 0.95);
  color: #fff;
}

.icon-inline {
  width: 16px;
  height: 16px;
}

/* Toast Message */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(25, 3, 6, 0.92);
  border: 1px solid rgba(255, 50, 70, 0.4);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  color: #fff;
  padding: 0.65rem 1.25rem;
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 500;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.7), 0 0 15px rgba(255, 20, 50, 0.3);
  z-index: 200;
  animation: toastIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  pointer-events: none;
}

@keyframes toastIn {
  from { opacity: 0; transform: translate(-50%, 15px); }
  to { opacity: 1; transform: translate(-50%, 0); }
}

/* Mobile Responsiveness */
@media (max-width: 640px) {
  .top-nav {
    top: 0.6rem;
    left: 0.6rem;
    right: 0.6rem;
  }

  .brand-text {
    display: none;
  }

  .brand {
    padding: 0.4rem 0.6rem;
  }

  .ctrl-btn .btn-label {
    display: none;
  }

  .ctrl-btn {
    padding: 0;
    width: 44px;
    height: 44px;
  }

  .modal-actions {
    flex-direction: column;
    width: 100%;
  }

  .modal-actions button {
    width: 100%;
    justify-content: center;
  }
}

/* Accessibility: Prefers Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  .heart-pulse-icon {
    animation: none;
  }

  .burst-heart {
    animation: none;
    display: none;
  }

  .top-nav {
    transition: none;
  }

  .ctrl-btn {
    transition: none;
  }
}