/* Базовые сбросы и переменные */
:root {
  --valentine-red: #c41e3a;
  --valentine-pink: #ff69b4;
  --valentine-rose: #e8a0a0;
  --valentine-light: #fff0f5;
  --valentine-white: #fff;
  --shadow: 0 4px 12px rgba(196, 30, 58, 0.25);
  --transition-screen: 400ms ease;
  --transition-slide: 350ms ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  height: 100%;
  -webkit-font-smoothing: antialiased;
}

body {
  margin: 0;
  height: 100vh;
  min-height: 100vh;
  font-family: 'Comfortaa', sans-serif;
  background: linear-gradient(135deg, #fff0f5 0%, #ffe4ec 40%, #ffd6e0 100%);
  color: #333;
  overflow: hidden;
}

.app {
  position: relative;
  height: 100vh;
  max-width: 600px;
  margin: 0 auto;
  padding: 1.5rem;
  overflow: hidden;
}

/* Фон с сердечками */
.hearts-bg {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.hearts-bg::before,
.hearts-bg::after {
  content: '♥';
  position: absolute;
  font-size: 1.2rem;
  color: var(--valentine-rose);
  opacity: 0.35;
  animation: float 6s ease-in-out infinite;
}

.hearts-bg::before {
  top: 10%;
  left: 8%;
  animation-delay: 0s;
}

.hearts-bg::after {
  top: 25%;
  right: 12%;
  animation-delay: 2s;
}

@keyframes float {
  0%, 100% { transform: translateY(0) scale(1); opacity: 0.35; }
  50% { transform: translateY(-8px) scale(1.05); opacity: 0.5; }
}

/* Декоративные сердечки через псевдоэлементы контейнера */
.app::before {
  content: '♥';
  position: absolute;
  bottom: 15%;
  right: 5%;
  font-size: 1rem;
  color: var(--valentine-pink);
  opacity: 0.3;
  animation: pulse 3s ease-in-out infinite;
}

.app::after {
  content: '♥';
  position: absolute;
  top: 60%;
  left: 5%;
  font-size: 0.9rem;
  color: var(--valentine-rose);
  opacity: 0.25;
  animation: pulse 4s ease-in-out infinite 1s;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 0.25; }
  50% { transform: scale(1.15); opacity: 0.4; }
}

/* Дополнительные сердечки в фоне */
.hearts-bg .heart {
  position: absolute;
  color: var(--valentine-rose);
  opacity: 0.3;
  font-size: 1rem;
  pointer-events: none;
}

.hearts-bg .heart--1 { top: 5%; left: 15%; font-size: 0.9rem; color: var(--valentine-pink); animation: float 5s ease-in-out infinite; animation-delay: 0.5s; }
.hearts-bg .heart--2 { top: 15%; right: 20%; font-size: 1.2rem; opacity: 0.35; animation: sway 6s ease-in-out infinite; animation-delay: 1s; }
.hearts-bg .heart--3 { top: 45%; left: 5%; font-size: 0.85rem; opacity: 0.25; animation: float 7s ease-in-out infinite; animation-delay: 2.5s; }
.hearts-bg .heart--4 { top: 50%; right: 8%; font-size: 1.1rem; color: var(--valentine-pink); animation: sway 5s ease-in-out infinite; animation-delay: 0s; }
.hearts-bg .heart--5 { top: 75%; left: 18%; font-size: 1rem; opacity: 0.4; animation: float 6s ease-in-out infinite; animation-delay: 1.5s; }
.hearts-bg .heart--6 { top: 80%; right: 15%; font-size: 0.95rem; animation: sway 8s ease-in-out infinite; animation-delay: 3s; }
.hearts-bg .heart--7 { top: 30%; left: 25%; font-size: 1.15rem; opacity: 0.35; animation: float 4s ease-in-out infinite; animation-delay: 2s; }
.hearts-bg .heart--8 { top: 65%; left: 30%; font-size: 0.9rem; color: var(--valentine-pink); animation: sway 7s ease-in-out infinite; animation-delay: 0.8s; }
.hearts-bg .heart--9 { top: 10%; right: 35%; font-size: 1.05rem; opacity: 0.28; animation: float 5.5s ease-in-out infinite; animation-delay: 1.8s; }
.hearts-bg .heart--10 { top: 55%; right: 28%; font-size: 0.85rem; opacity: 0.45; animation: sway 6.5s ease-in-out infinite; animation-delay: 2.2s; }

@keyframes sway {
  0%, 100% { transform: translateX(0) scale(1); }
  50% { transform: translateX(10px) scale(1.08); }
}

/* Искорки */
.hearts-bg .sparkle {
  position: absolute;
  font-size: 0.75rem;
  color: #e8b4c8;
  opacity: 0.4;
  pointer-events: none;
}

.hearts-bg .sparkle--1 { top: 20%; left: 40%; animation: twinkle 3s ease-in-out infinite; animation-delay: 0s; }
.hearts-bg .sparkle--2 { top: 35%; right: 25%; color: #f0c0d0; animation: twinkle 2.5s ease-in-out infinite; animation-delay: 0.5s; }
.hearts-bg .sparkle--3 { top: 70%; left: 45%; animation: twinkle 3.5s ease-in-out infinite; animation-delay: 1s; }
.hearts-bg .sparkle--4 { top: 40%; left: 80%; animation: twinkle 2.8s ease-in-out infinite; animation-delay: 1.5s; }
.hearts-bg .sparkle--5 { top: 85%; right: 40%; animation: twinkle 3.2s ease-in-out infinite; animation-delay: 0.3s; }

@keyframes twinkle {
  0%, 100% { opacity: 0.3; transform: scale(1); }
  50% { opacity: 0.7; transform: scale(1.2); }
}

/* Экраны — все в одном месте, друг на друге */
.screen {
  position: absolute;
  inset: 0;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateX(20px);
  transition: opacity var(--transition-screen), visibility var(--transition-screen), transform var(--transition-screen);
  pointer-events: none;
}

.screen.active {
  opacity: 1;
  visibility: visible;
  transform: translateX(0);
  pointer-events: auto;
}

.screen.leaving {
  opacity: 0;
  visibility: hidden;
  transform: translateX(-20px);
}

.screen-content {
  text-align: center;
  padding: 1rem;
}

/* Экран 1 — приветствие */
.welcome-text {
  font-family: 'Caveat', cursive;
  font-size: clamp(1.5rem, 5vw, 2.2rem);
  font-weight: 500;
  line-height: 1.4;
  margin: 0 0 2rem;
  color: #5c2a2a;
}

/* Экран 2 — 35 причин */
.intro-text {
  font-family: 'Caveat', cursive;
  font-size: clamp(1.8rem, 6vw, 2.5rem);
  font-weight: 700;
  margin: 0 0 2rem;
  color: #5c2a2a;
}

/* Кнопки */
.btn {
  position: relative;
  font-family: 'Comfortaa', sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  padding: 0.75rem 1.75rem;
  border: none;
  border-radius: 2rem;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  box-shadow: var(--shadow);
}

.btn-primary {
  background: linear-gradient(145deg, var(--valentine-red), var(--valentine-pink));
  color: var(--valentine-white);
}

.btn-primary:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 20px rgba(196, 30, 58, 0.35);
}

.btn-primary::after,
.btn-love::after {
  content: '♥';
  position: absolute;
  top: -0.5em;
  left: 50%;
  transform: translateX(-50%) scale(0);
  font-size: 0.9em;
  color: var(--valentine-pink);
  opacity: 0;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.btn-primary:hover::after,
.btn-love:hover::after {
  transform: translateX(-50%) scale(1);
  opacity: 0.9;
}

.btn-primary:active {
  transform: scale(0.98);
}

/* Экран 3 — слайд-шоу */
.screen-slides {
  padding-bottom: 5rem;
}

.slide-area {
  text-align: center;
  padding: 1rem;
  min-height: 120px;
}

.slide-static {
  font-family: 'Caveat', cursive;
  font-size: clamp(1.4rem, 4vw, 1.9rem);
  margin: 0 0 0.5rem;
  color: #5c2a2a;
}

.slide-word-wrap {
  position: relative;
  min-height: 2.5em;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Два слоя для плавной смены слова — transition вместо keyframes */
.slide-word {
  font-family: 'Caveat', cursive;
  font-size: 74px;
  font-weight: 700;
  color: var(--valentine-red);
  display: inline-block;
  transition: transform 0.45s cubic-bezier(0.25, 0.46, 0.45, 0.94), opacity 0.45s ease;
}

.slide-word-aux {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  opacity: 0;
  pointer-events: none;
  text-align: center;
}

.slide-word-aux.slide-in-next {
  transform: translateY(-50%) translateX(0);
  opacity: 1;
}

.slide-word-aux.slide-in-prev {
  transform: translateY(-50%) translateX(0);
  opacity: 1;
}

.slide-word-aux.slide-from-right {
  transform: translateY(-50%) translateX(36px);
  opacity: 0;
}

.slide-word-aux.slide-from-left {
  transform: translateY(-50%) translateX(-36px);
  opacity: 0;
}

.slide-word.slide-out-next {
  transform: translateX(-36px);
  opacity: 0;
}

.slide-word.slide-out-prev {
  transform: translateX(36px);
  opacity: 0;
}

/* Стрелки навигации */
.nav-arrow {
  position: absolute;
  bottom: 1.5rem;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background: linear-gradient(145deg, var(--valentine-red), var(--valentine-pink));
  color: var(--valentine-white);
  font-size: 1.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  z-index: 2;
}

.nav-arrow:hover {
  transform: scale(1.1);
  box-shadow: 0 6px 20px rgba(196, 30, 58, 0.35);
}

.nav-prev {
  left: 1rem;
}

.nav-next {
  right: 1rem;
}

/* Кнопка «Я тебя тоже люблю» */
.love-btn-wrap {
  position: absolute;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  visibility: hidden;
  transform: translateX(-50%) scale(0.8);
  transition: opacity 0.4s ease, visibility 0.4s ease, transform 0.4s ease;
  z-index: 2;
}

.love-btn-wrap.visible {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) scale(1);
}

.btn-love {
  background: linear-gradient(145deg, var(--valentine-red), var(--valentine-pink));
  color: var(--valentine-white);
}

.btn-love:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 20px rgba(196, 30, 58, 0.35);
}

/* Взрыв сердечек по клику */
.heart-burst {
  position: fixed;
  font-size: 1rem;
  color: var(--valentine-pink);
  pointer-events: none;
  animation: heartBurst 1.4s ease-out forwards;
}

@keyframes heartBurst {
  0% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(0);
  }
  30% {
    opacity: 1;
    transform: translate(calc(-50% + var(--burst-x)), calc(-50% + var(--burst-y))) scale(1.2);
  }
  100% {
    opacity: 0;
    transform: translate(calc(-50% + var(--burst-x)), calc(-50% + var(--burst-y))) scale(0.8);
  }
}

/* Экран 4 — финал */
.screen-final .screen-content {
  animation: finalAppear 0.6s ease forwards;
}

@keyframes finalAppear {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.final-text-wrap {
  position: relative;
  padding: 1rem 2rem;
}

.final-text-wrap::before {
  content: '';
  position: absolute;
  inset: -0.5rem;
  border-radius: 1rem;
  background: radial-gradient(circle at center, rgba(255, 240, 245, 0.6) 0%, transparent 70%);
  opacity: 0.8;
  animation: finalGlow 2.5s ease-in-out infinite;
  pointer-events: none;
}

@keyframes finalGlow {
  0%, 100% { opacity: 0.6; filter: brightness(1); }
  50% { opacity: 0.9; filter: brightness(1.05); }
}

.final-decor {
  position: absolute;
  font-size: 1.25rem;
  color: var(--valentine-pink);
  opacity: 0.6;
  animation: twinkle 2s ease-in-out infinite;
}

.final-decor--tl { top: -0.25rem; left: 0; animation-delay: 0s; }
.final-decor--tr { top: -0.25rem; right: 0; animation-delay: 0.5s; }
.final-decor--bl { bottom: -0.25rem; left: 0.5rem; font-size: 1rem; animation-delay: 0.3s; }
.final-decor--br { bottom: -0.25rem; right: 0.5rem; font-size: 1rem; animation-delay: 0.7s; }

.final-text {
  font-family: 'Caveat', cursive;
  font-size: clamp(2rem, 8vw, 3.5rem);
  font-weight: 700;
  margin: 0;
  color: var(--valentine-red);
  letter-spacing: 0.02em;
  position: relative;
  z-index: 1;
}

/* Адаптивность */
@media (max-width: 480px) {
  .app {
    padding: 1rem;
  }

  .nav-arrow {
    width: 44px;
    height: 44px;
    bottom: 1rem;
  }

  .nav-prev {
    left: 0.5rem;
  }

  .nav-next {
    right: 0.5rem;
  }

  .love-btn-wrap {
    bottom: 1rem;
    padding: 0 0.5rem;
  }

  .btn {
    padding: 0.65rem 1.4rem;
    font-size: 1rem;
  }
}