:root {
  --bg1: #673147;
  --bg2: #4f2537;
  --bg3: #3a1927;
  --cream: #FFFCEF;
  --from: #6ec0a7;
  --text: #2e2431;
  --muted: #5a4a55;
  --shadow: rgba(0, 0, 0, 0.35);
  --accent: #c5a7ff;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
}

body {
  margin: 0;
  font-family: 'Poppins', system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  color: var(--cream);
  background:
    radial-gradient(1200px 800px at 10% 10%, var(--bg2) 0%, transparent 70%),
    radial-gradient(900px 600px at 90% 20%, var(--bg3) 0%, transparent 70%),
    linear-gradient(160deg, var(--bg1) 0%, var(--bg2) 100%);
  overflow: hidden;
}

#confetti {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.scene {
  position: relative;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: clamp(12px, 4vw, 32px);
}

.envelope {
  border: none;
  background: transparent;
  padding: 0;
  cursor: pointer;
  perspective: 1200px;
  width: clamp(260px, 50vw, 560px);
  height: clamp(180px, 36vw, 380px);
  will-change: transform;
  z-index: 10;
  position: relative;
}

.env-body {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
}

.front {
  position: absolute;
  inset: 0;
  background: var(--cream);
  border-radius: clamp(10px, 2.4vw, 18px);
  box-shadow: 0 18px 40px var(--shadow);
  display: grid;
  place-items: center;
  transform: translateZ(1px);
}

.from {
  color: var(--text);
  font-weight: 700;
  letter-spacing: 0.5px;
  font-size: clamp(18px, 3.6vw, 28px);
}

.flap {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 56%;
  background: var(--cream);
  border-radius: clamp(10px, 2.4vw, 18px) clamp(10px, 2.4vw, 18px) 0 0;
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  transform-origin: top center;
  transform: rotateX(0deg) translateZ(2px);
  filter: drop-shadow(0 2px 4px rgba(0,0,0,0.15));
  z-index: 2;
  border-bottom: 2px solid rgba(0,0,0,0.06);
}
.flap::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, rgba(0,0,0,0.08), transparent);
  pointer-events: none;
}

.letter {
  position: fixed;
  left: 50%;
  top: 50%;
  width: clamp(260px, 50vw, 560px);
  max-width: 90vw;
  transform: translate(-50%, -50%) scale(0.1);
  background: #ffffff;
  color: #333;
  border-radius: clamp(8px, 2vw, 14px);
  box-shadow: 0 16px 36px rgba(0,0,0,0.2);
  padding: clamp(24px, 4vw, 32px);
  opacity: 0;
  pointer-events: none;
  z-index: 5;
  will-change: transform, opacity;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}
.letter-visible {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1);
  transition: transform 3000ms cubic-bezier(.2,.8,.2,1), opacity 1000ms ease;
  pointer-events: auto;
}

.letter-title {
  margin: 0 0 8px;
  font-family: 'Dancing Script', cursive;
  font-size: clamp(28px, 5vw, 42px);
  color: #1a1a1a;
}
.letter-text {
  margin: 0;
  font-family: 'Dancing Script', cursive;
  font-size: clamp(18px, 3.5vw, 24px);
  line-height: 1.4;
  color: #4a4a4a;
}

.envelope.descend {
  transform: translateY(70vh);
  transition: transform 1600ms ease;
}

.envelope.opened .flap {
  transform: rotateX(-180deg) translateZ(2px);
  transition: transform 700ms cubic-bezier(.2,.8,.2,1) 100ms;
}

.front .from {
  position: relative;
  z-index: 1;
  justify-self: center;
  align-self: end;
  margin-bottom: clamp(14px, 3vw, 24px);
  color: var(--from);
  text-shadow: 0 2px 8px rgba(0,0,0,0.08);
}
.front::before,
.front::after {
  content: "";
  position: absolute;
  bottom: 0;
  width: 50%;
  height: 60%;
  background: var(--cream);
  z-index: 0;
  border-top: 1px solid rgba(0,0,0,0.06);
}
.front::before {
  left: 0;
  clip-path: polygon(0 0, 100% 100%, 0 100%);
}
.front::after {
  right: 0;
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
}

.footer {
  margin-top: clamp(16px, 4vw, 28px);
  font-size: clamp(12px, 2.6vw, 14px);
  color: #ffe7f2;
}