:root {
  /* Default Theme (Modern Dark) */
  --bg-color: #0f172a;
  --text-color: #f8fafc;
  --text-muted: #94a3b8;
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --secondary-color: #1e293b;
  --accent-color: #60a5fa;
  --font-heading: 'Inter', sans-serif;
  --font-body: 'Inter', sans-serif;
  --blob-1: rgba(59, 130, 246, 0.3);
  --blob-2: rgba(147, 51, 234, 0.3);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --glass-bg: rgba(30, 41, 59, 0.7);
  --glass-border: rgba(255, 255, 255, 0.1);
}

[data-theme="wedding-minimal"] {
  --bg-color: #fcfcfc;
  --text-color: #1a1a1a;
  --text-muted: #666666;
  --primary-color: #333333;
  --primary-hover: #555555;
  --secondary-color: #f0f0f0;
  --accent-color: #e0e0e0;
  --font-heading: 'Inter', sans-serif;
  --blob-1: rgba(0, 0, 0, 0.05);
  --blob-2: rgba(0, 0, 0, 0.05);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.1);
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(0, 0, 0, 0.05);
}

[data-theme="wedding-boho"] {
  --bg-color: #fdfbf7;
  --text-color: #4a3f35;
  --text-muted: #7d6b5d;
  --primary-color: #8b7355;
  --primary-hover: #6b5840;
  --secondary-color: #f5f0ea;
  --accent-color: #d2b48c;
  --font-heading: 'Playfair Display', serif;
  --blob-1: rgba(139, 115, 85, 0.15);
  --blob-2: rgba(210, 180, 140, 0.15);
  --card-shadow: 0 25px 50px -12px rgba(74, 63, 53, 0.1);
  --glass-bg: rgba(253, 251, 247, 0.8);
  --glass-border: rgba(139, 115, 85, 0.1);
}

[data-theme="wedding-classic"] {
  --bg-color: #fafaf9;
  --text-color: #1c1917;
  --text-muted: #57534e;
  --primary-color: #d4af37;
  --primary-hover: #b8972e;
  --secondary-color: #f5f5f4;
  --accent-color: #facc15;
  --font-heading: 'Playfair Display', serif;
  --blob-1: rgba(212, 175, 55, 0.2);
  --blob-2: rgba(253, 230, 138, 0.3);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.1);
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(0, 0, 0, 0.05);
}

[data-theme="birthday-retro"] {
  --bg-color: #1a0033;
  --text-color: #ffffff;
  --text-muted: #b3b3b3;
  --primary-color: #ff00ff;
  --primary-hover: #cc00cc;
  --secondary-color: #330066;
  --accent-color: #00ffff;
  --font-heading: 'Outfit', sans-serif;
  --blob-1: rgba(255, 0, 255, 0.4);
  --blob-2: rgba(0, 255, 255, 0.4);
  --card-shadow: 0 25px 50px -12px rgba(255, 0, 255, 0.3);
  --glass-bg: rgba(26, 0, 51, 0.7);
  --glass-border: rgba(255, 255, 255, 0.1);
}

[data-theme="birthday-loft"] {
  --bg-color: #1e1e24;
  --text-color: #f0f0f0;
  --text-muted: #999999;
  --primary-color: #c44536;
  --primary-hover: #a1362a;
  --secondary-color: #2b2b33;
  --accent-color: #f7b267;
  --font-heading: 'Inter', sans-serif;
  --blob-1: rgba(196, 69, 54, 0.2);
  --blob-2: rgba(247, 178, 103, 0.2);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --glass-bg: rgba(30, 30, 36, 0.8);
  --glass-border: rgba(255, 255, 255, 0.05);
}

[data-theme="birthday-banquet"] {
  --bg-color: #121212;
  --text-color: #ffffff;
  --text-muted: #cccccc;
  --primary-color: #800020;
  --primary-hover: #5c0017;
  --secondary-color: #1f1f1f;
  --accent-color: #ffd700;
  --font-heading: 'Playfair Display', serif;
  --blob-1: rgba(128, 0, 32, 0.4);
  --blob-2: rgba(255, 215, 0, 0.2);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --glass-bg: rgba(18, 18, 18, 0.8);
  --glass-border: rgba(255, 215, 0, 0.1);
}

[data-theme="gender-teddy"] {
  --bg-color: #faf5f0;
  --text-color: #5c4d3c;
  --text-muted: #8c7b6b;
  --primary-color: #c2a88f;
  --primary-hover: #a68c74;
  --secondary-color: #f0e6d8;
  --accent-color: #e6d5c3;
  --font-heading: 'Outfit', sans-serif;
  --blob-1: rgba(194, 168, 143, 0.2);
  --blob-2: rgba(230, 213, 195, 0.3);
  --card-shadow: 0 25px 50px -12px rgba(92, 77, 60, 0.1);
  --glass-bg: rgba(250, 245, 240, 0.8);
  --glass-border: rgba(194, 168, 143, 0.2);
}

[data-theme="gender-stars"] {
  --bg-color: #0b1021;
  --text-color: #ffffff;
  --text-muted: #b0c4de;
  --primary-color: #ffd700;
  --primary-hover: #ccac00;
  --secondary-color: #151b33;
  --accent-color: #c0c0c0;
  --font-heading: 'Outfit', sans-serif;
  --blob-1: rgba(255, 215, 0, 0.15);
  --blob-2: rgba(192, 192, 192, 0.15);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --glass-bg: rgba(11, 16, 33, 0.7);
  --glass-border: rgba(255, 215, 0, 0.1);
}

[data-theme="gender-pinkblue"] {
  --bg-color: #2b2b2b;
  --text-color: #ffffff;
  --text-muted: #cccccc;
  --primary-color: #ffb6c1;
  --primary-hover: #ff99a8;
  --secondary-color: #383838;
  --accent-color: #87cefa;
  --font-heading: 'Outfit', sans-serif;
  --blob-1: rgba(255, 182, 193, 0.3);
  --blob-2: rgba(135, 206, 250, 0.3);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --glass-bg: rgba(43, 43, 43, 0.8);
  --glass-border: rgba(255, 255, 255, 0.1);
}

[data-theme="corporate-eco"] {
  --bg-color: #f1f8e9;
  --text-color: #1b5e20;
  --text-muted: #4caf50;
  --primary-color: #4caf50;
  --primary-hover: #388e3c;
  --secondary-color: #dcedc8;
  --accent-color: #81c784;
  --font-heading: 'Inter', sans-serif;
  --blob-1: rgba(76, 175, 80, 0.2);
  --blob-2: rgba(129, 199, 132, 0.2);
  --card-shadow: 0 25px 50px -12px rgba(27, 94, 32, 0.1);
  --glass-bg: rgba(241, 248, 233, 0.8);
  --glass-border: rgba(76, 175, 80, 0.2);
}

[data-theme="corporate-gatsby"] {
  --bg-color: #111111;
  --text-color: #f8f4e6;
  --text-muted: #c2a878;
  --primary-color: #d4af37;
  --primary-hover: #b5952f;
  --secondary-color: #1a1a1a;
  --accent-color: #e5c158;
  --font-heading: 'Playfair Display', serif;
  --blob-1: rgba(212, 175, 55, 0.15);
  --blob-2: rgba(181, 149, 47, 0.1);
  --card-shadow: 0 25px 50px -12px rgba(212, 175, 55, 0.2);
  --glass-bg: rgba(17, 17, 17, 0.85);
  --glass-border: rgba(212, 175, 55, 0.2);
}

[data-theme="corporate-gala"] {
  --bg-color: #001e3c;
  --text-color: #ffffff;
  --text-muted: #b0bec5;
  --primary-color: #1565c0;
  --primary-hover: #0d47a1;
  --secondary-color: #002855;
  --accent-color: #e0e0e0;
  --font-heading: 'Playfair Display', serif;
  --blob-1: rgba(21, 101, 192, 0.3);
  --blob-2: rgba(224, 224, 224, 0.1);
  --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --glass-bg: rgba(0, 30, 60, 0.8);
  --glass-border: rgba(255, 255, 255, 0.05);
}

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-color);
  color: var(--text-color);
  transition: background-color 1s cubic-bezier(0.4, 0, 0.2, 1), 
              color 1s cubic-bezier(0.4, 0, 0.2, 1);
  overflow-x: hidden;
  line-height: 1.6;
}

h1, h2, h3, .logo {
  font-family: var(--font-heading);
  transition: font-family 1s ease, color 1s ease;
}

a {
  text-decoration: none;
  color: inherit;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.text-center {
  text-align: center;
}

.mt-4 { margin-top: 2rem; }

/* Background Blobs */
.background-effects {
  position: fixed;
  top: 0; left: 0; width: 100%; height: 100%;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}
.blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(100px);
  transition: background-color 1s ease, transform 10s ease-in-out infinite alternate;
}
.blob-1 {
  width: 45vw; height: 45vw;
  top: -10%; left: -10%;
  background-color: var(--blob-1);
}
.blob-2 {
  width: 50vw; height: 50vw;
  bottom: -10%; right: -10%;
  background-color: var(--blob-2);
  transform-origin: center;
}

/* Background Video */
.bg-video {
  position: fixed;
  top: 50%;
  left: 50%;
  min-width: 100%;
  min-height: 100%;
  width: auto;
  height: auto;
  transform: translateX(-50%) translateY(-50%);
  object-fit: cover;
  opacity: 0;
  z-index: -2;
  transition: opacity 1s ease;
  pointer-events: none;
}
.bg-video.show {
  opacity: 0.25; /* Лёгкая прозрачность, чтобы не мешать контенту */
}

/* Particles Background */
.particles-bg {
  position: fixed;
  top: 0; left: 0; width: 100%; height: 100%;
  z-index: -2;
  pointer-events: none;
}

/* Header */
.header {
  padding: 24px 0;
  position: fixed;
  top: 0; left: 0; width: 100%;
  z-index: 100;
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--glass-border);
  transition: background 1s ease, border-color 1s ease;
}
.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo {
  font-size: 1.75rem;
  font-weight: 800;
  letter-spacing: -0.05em;
  color: var(--primary-color);
  transition: color 1s ease;
}
.nav {
  display: flex;
  gap: 2rem;
  align-items: center;
}
.nav-link {
  font-weight: 500;
  transition: color 0.3s ease;
}
.nav-link:hover {
  color: var(--primary-color);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 10px 24px;
  border-radius: 9999px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
  font-family: inherit;
  font-size: 1rem;
}
.btn-primary {
  background-color: var(--primary-color);
  color: #fff;
}
.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
}
.btn-large {
  padding: 16px 40px;
  font-size: 1.125rem;
}
.glow-effect {
  box-shadow: 0 0 20px var(--blob-1);
}

/* Hero Section */
.hero {
  padding: 200px 0 100px;
  min-height: 60vh;
  display: flex;
  align-items: center;
  text-align: center;
}
.main-title {
  font-size: 4.5rem;
  line-height: 1.1;
  margin-bottom: 1.5rem;
  background: linear-gradient(135deg, var(--text-color), var(--text-muted));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  transition: all 1s ease;
}
.subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto;
  transition: color 1s ease;
}

/* Interactive Section */
.interactive-section {
  padding: 100px 0;
}
.section-title {
  font-size: 2.5rem;
  margin-bottom: 2rem;
}
.filter-controls {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 4rem;
  flex-wrap: wrap;
}
.filter-btn {
  background: transparent;
  border: 1px solid var(--text-muted);
  color: var(--text-muted);
  padding: 8px 20px;
  border-radius: 9999px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: inherit;
  font-size: 1rem;
}
.filter-btn:hover, .filter-btn.active {
  border-color: var(--primary-color);
  color: var(--primary-color);
}
.filter-btn.active {
  background: var(--primary-color);
  color: #fff;
}

/* Switch Toggle (Video Preview) */
.video-preview-toggle {
  margin-bottom: 2rem;
}
.switch-label {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  cursor: pointer;
}
.switch-text {
  font-weight: 500;
  color: var(--text-color);
}
.switch {
  position: relative;
  display: inline-block;
  width: 50px;
  height: 28px;
}
.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}
.slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: rgba(255, 255, 255, 0.2);
  transition: .4s;
  border: 1px solid var(--glass-border);
}
.slider:before {
  position: absolute;
  content: "";
  height: 20px;
  width: 20px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .4s;
}
.slider.round {
  border-radius: 34px;
}
.slider.round:before {
  border-radius: 50%;
}
input:checked + .slider {
  background-color: var(--primary-color);
  border-color: var(--primary-color);
}
input:checked + .slider:before {
  transform: translateX(22px);
}

/* Coverflow Carousel */
.carousel-wrapper {
  position: relative;
  width: 100%;
  height: 600px;
  perspective: 1500px;
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: 4rem;
  overflow: hidden;
}
.coverflow {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
}
.card {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 320px;
  height: 480px;
  margin-left: -160px;
  margin-top: -240px;
  border-radius: 20px;
  background-size: cover;
  background-position: center;
  box-shadow: var(--card-shadow);
  transition: transform 0.6s cubic-bezier(0.2, 0.8, 0.2, 1), 
              opacity 0.6s cubic-bezier(0.2, 0.8, 0.2, 1),
              filter 0.6s ease;
  cursor: pointer;
  -webkit-box-reflect: below 15px linear-gradient(transparent, transparent, rgba(0,0,0,0.2));
}

/* Card States applied by JS */
.card.active {
  transform: translate3d(0, 0, 200px) rotateY(0deg);
  opacity: 1;
  filter: blur(0px);
  z-index: 10;
}
.card.prev {
  transform: translate3d(-35%, 0, -100px) rotateY(45deg);
  opacity: 0.7;
  filter: blur(4px);
  z-index: 5;
}
.card.next {
  transform: translate3d(35%, 0, -100px) rotateY(-45deg);
  opacity: 0.7;
  filter: blur(4px);
  z-index: 5;
}
.card.hidden-left {
  transform: translate3d(-70%, 0, -300px) rotateY(60deg);
  opacity: 0;
  z-index: 1;
}
.card.hidden-right {
  transform: translate3d(70%, 0, -300px) rotateY(-60deg);
  opacity: 0;
  z-index: 1;
}

/* Carousel Nav */
.carousel-nav {
  position: absolute;
  top: 50%;
  left: 0;
  width: 100%;
  transform: translateY(-50%);
  display: flex;
  justify-content: space-between;
  padding: 0 10%;
  pointer-events: none;
  z-index: 20;
}
.nav-btn {
  pointer-events: auto;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  color: var(--text-color);
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  transition: all 0.3s ease;
  backdrop-filter: blur(8px);
}
.nav-btn:hover {
  background: var(--primary-color);
  color: #fff;
  transform: scale(1.1);
}

/* Selected Info */
.selected-info {
  max-width: 600px;
  margin: 0 auto;
  animation: fadeIn 0.5s ease;
}
.selected-title {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: var(--primary-color);
}
.selected-desc {
  color: var(--text-muted);
  font-size: 1.125rem;
}

/* Features Section */
.features-section {
  padding: 80px 0;
  position: relative;
  z-index: 2;
}
.features-stack {
  display: flex;
  flex-direction: column;
  gap: 100px;
  margin-top: 60px;
}
.feature-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}
.feature-info {
  margin-bottom: 2rem;
  max-width: 600px;
}
.feature-info h3 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: var(--primary-color);
  transition: color 0.8s ease;
  font-family: var(--font-heading);
}
.feature-info p {
  color: var(--text-muted);
  font-size: 1.125rem;
}

/* Interactive Widgets */
.feature-demo {
  display: flex;
  justify-content: center;
  align-items: center;
  transition: all 0.8s ease;
}
.large-preview {
  width: 100%;
  max-width: 800px;
  background: transparent;
  border: none;
  padding: 0;
  min-height: auto;
}

/* Gallery Preview */
.gallery-preview {
  display: flex;
  gap: 20px;
  width: 100%;
  max-width: 800px;
  overflow-x: auto;
  padding: 20px;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  justify-content: flex-start;
}
.gallery-preview::-webkit-scrollbar {
  height: 8px;
}
.gallery-preview::-webkit-scrollbar-track {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 10px;
}
.gallery-preview::-webkit-scrollbar-thumb {
  background: var(--primary-color);
  border-radius: 10px;
}
.gal-img {
  flex: 0 0 auto;
  width: 240px;
  height: 320px;
  background: var(--glass-bg);
  border-radius: 12px;
  transition: transform 0.4s ease, box-shadow 0.4s ease;
  object-fit: cover;
  box-shadow: var(--card-shadow);
  scroll-snap-align: center;
}
.gal-img:hover {
  transform: translateY(-10px) scale(1.02);
  box-shadow: 0 30px 60px -12px rgba(0,0,0,0.5);
}

/* Music Preview */
.music-preview {
  flex-direction: column;
  gap: 15px;
  width: 100%;
}

.styled-select.large-select {
  padding: 14px 20px;
  font-size: 1.1rem;
  border-radius: 12px;
}
.audio-player {
  width: 100%;
  max-width: 500px;
  margin: 0 auto;
}
.styled-audio.large-audio {
  height: 54px;
}
.styled-select option {
  background: var(--bg-color);
  color: var(--text-color);
}
.audio-player {
  width: 100%;
}
.styled-audio {
  width: 100%;
  height: 40px;
  outline: none;
}
/* Немного стилизуем стандартный аудиоплеер где возможно */
.styled-audio::-webkit-media-controls-panel {
  background-color: var(--glass-bg);
}
.styled-audio::-webkit-media-controls-current-time-display,
.styled-audio::-webkit-media-controls-time-remaining-display {
  color: var(--text-color);
}

/* Timer Preview */
.timer-preview {
  gap: 10px;
  flex-wrap: wrap;
}
.timer-box.large-timer-box {
  padding: 20px 30px;
  border-radius: 16px;
  border: 2px solid var(--primary-color);
  min-width: 120px;
  box-shadow: var(--card-shadow);
}
.t-num {
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--text-color);
  font-family: var(--font-heading);
}
.t-lbl {
  font-size: 1rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* RSVP Preview */
.rsvp-preview {
  flex-direction: column;
  gap: 15px;
  width: 100%;
  max-width: 400px;
  margin: 0 auto;
}
.mock-input {
  width: 100%;
  padding: 16px 20px;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  color: var(--text-color);
  font-size: 1.1rem;
  font-family: inherit;
  outline: none;
  transition: all 0.3s ease;
}
.mock-input:focus {
  border-color: var(--primary-color);
}
textarea.mock-input {
  resize: vertical;
}
.mock-btn {
  width: 100%;
  padding: 16px;
  background: var(--primary-color);
  color: #fff;
  border-radius: 12px;
  font-size: 1.1rem;
  font-weight: 600;
  transition: background 0.8s ease;
  border: none;
  cursor: pointer;
  font-family: inherit;
}
.mock-btn:hover {
  background: var(--primary-hover);
}
.mock-input option {
  background: var(--bg-color);
  color: var(--text-color);
}

/* Order Section */
.order-section {
  padding: 80px 0 120px;
  position: relative;
  z-index: 2;
}
.order-box {
  max-width: 600px;
  margin: 0 auto;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  padding: 3rem;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--card-shadow);
}
.mb-4 {
  margin-bottom: 2rem;
}
.w-100 {
  width: 100%;
}
.order-form {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.form-group label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-color);
}
.form-group input,
.form-group textarea {
  width: 100%;
  padding: 14px 16px;
  background: rgba(0, 0, 0, 0.2);
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  color: var(--text-color);
  font-family: inherit;
  font-size: 1rem;
  transition: all 0.3s ease;
}
.form-group textarea {
  resize: vertical;
}
.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary-color);
  background: rgba(0, 0, 0, 0.4);
  box-shadow: 0 0 0 2px var(--blob-1);
}
.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--text-muted);
  opacity: 0.5;
}

/* Custom Checkbox in Form */
.checkbox-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 10px;
  margin-top: 0.5rem;
}
.checkbox-label {
  display: flex;
  align-items: center;
  position: relative;
  padding-left: 35px;
  margin-bottom: 12px;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--text-color);
  user-select: none;
}
.checkbox-label input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}
.checkmark {
  position: absolute;
  top: 0;
  left: 0;
  height: 24px;
  width: 24px;
  background-color: rgba(0,0,0,0.2);
  border: 1px solid var(--glass-border);
  border-radius: 6px;
  transition: all 0.3s ease;
}
.checkbox-label:hover input ~ .checkmark {
  border-color: var(--primary-color);
}
.checkbox-label input:checked ~ .checkmark {
  background-color: var(--primary-color);
  border-color: var(--primary-color);
}
.checkmark:after {
  content: "";
  position: absolute;
  display: none;
}
.checkbox-label input:checked ~ .checkmark:after {
  display: block;
}
.checkbox-label .checkmark:after {
  left: 8px;
  top: 4px;
  width: 6px;
  height: 12px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Footer */
.footer {
  padding: 40px 0;
  border-top: 1px solid var(--glass-border);
  color: var(--text-muted);
  margin-top: 100px;
}

/* Responsive */
@media (max-width: 768px) {
  .main-title { font-size: 2.5rem; }
  .card {
    width: 240px; height: 360px;
    margin-left: -120px; margin-top: -180px;
  }
  .card.prev { transform: translate3d(-40%, 0, -100px) rotateY(40deg); }
  .card.next { transform: translate3d(40%, 0, -100px) rotateY(-40deg); }
  .carousel-nav { padding: 0 5%; }
}