/* =========================================================================================
 * GIẤY THƯ: phong bì có vân giấy + hoa màu nước + dấu sáp (cảnh mở đầu và cảnh lá thư), tờ thư cuối
 * ========================================================================================= */

/* ---------------------------------------------------------------- Phong bì */
.envelope {
  position: relative;
  width: min(86vw, 340px);
  aspect-ratio: 3 / 2;
  padding: 0;
  border: 0;
  background: none;
  cursor: pointer;
  perspective: 900px;
  animation: wobble 3.2s ease-in-out infinite;
}

.envelope.open {
  animation: none;
  cursor: default;
}

.env-back,
.env-front,
.env-flap,
.env-card,
.wax {
  position: absolute;
  display: block;
}

/* Vân giấy: vài lớp sọc mờ chéo nhau trên nền hồng phấn */
.env-back,
.env-front,
.env-flap {
  background-color: #f7d3dc;
  background-image: repeating-linear-gradient(28deg, rgba(255, 255, 255, 0.16) 0 1px, transparent 1px 7px),
    repeating-linear-gradient(-62deg, rgba(190, 110, 140, 0.07) 0 1px, transparent 1px 9px),
    linear-gradient(160deg, #fde6ec, #f3c2cf);
}

.env-back {
  inset: 0;
  border-radius: 12px;
  box-shadow: 0 18px 40px rgba(110, 40, 70, 0.28);
  filter: brightness(0.93);
}

.env-card {
  left: 7%;
  right: 7%;
  top: 7%;
  height: 88%;
  padding: 16px 16px 0;
  border-radius: 10px;
  background: #fffdf8;
  box-shadow: 0 4px 14px rgba(120, 50, 80, 0.12);
  text-align: center;
  z-index: 2;
  transition: transform 1s cubic-bezier(0.3, 1.2, 0.4, 1) 0.55s;
}

.env-card-title {
  display: block;
  font-family: var(--font-hand);
  font-size: 1.7rem;
  font-weight: 700;
  color: var(--rose-deep);
}

.env-card-text {
  display: block;
  margin-top: 6px;
  font-size: 0.9rem;
  line-height: 1.45;
  color: var(--ink);
}

.env-front {
  inset: 0;
  z-index: 3;
  border-radius: 12px;
  clip-path: polygon(0 0, 50% 55%, 100% 0, 100% 100%, 0 100%);
}

.env-flowers {
  position: absolute;
  bottom: -6%;
  width: 36%;
  pointer-events: none;
}

.env-flowers svg {
  display: block;
  width: 100%;
}

.env-flowers.left {
  left: -6%;
}

.env-flowers.right {
  right: -6%;
}

.env-to {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 14%;
  font-family: var(--font-hand);
  font-size: 1.65rem;
  font-weight: 700;
  color: #9e2c52;
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.6);
}

.env-sub {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 6%;
  font-size: 0.66rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: #a86078;
}

.env-flap {
  top: 0;
  left: 0;
  right: 0;
  height: 60%;
  z-index: 4;
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  border-radius: 12px 12px 0 0;
  filter: brightness(0.97) drop-shadow(0 2px 2px rgba(120, 40, 70, 0.2));
  transform-origin: top center;
  transition: transform 0.6s ease 0.25s, z-index 0s linear 0.55s;
}

/* Dấu sáp: hai nửa ghép lại, mở thư thì nứt đôi rơi xuống */
.wax {
  left: 50%;
  top: 56%;
  width: 60px;
  height: 60px;
  margin: -30px 0 0 -30px;
  z-index: 5;
  filter: drop-shadow(0 4px 6px rgba(110, 20, 50, 0.35));
}

.wax-half {
  position: absolute;
  inset: 0;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.6, 1), opacity 0.6s ease;
}

.wax-half svg {
  display: block;
  width: 100%;
  height: 100%;
}

.wax-half.a {
  clip-path: polygon(0 0, 54% 0, 47% 28%, 56% 52%, 46% 76%, 52% 100%, 0 100%);
}

.wax-half.b {
  clip-path: polygon(54% 0, 100% 0, 100% 100%, 52% 100%, 46% 76%, 56% 52%, 47% 28%);
}

.envelope.open .wax-half.a {
  transform: translate(-18px, 46px) rotate(-28deg);
  opacity: 0;
}

.envelope.open .wax-half.b {
  transform: translate(18px, 52px) rotate(24deg);
  opacity: 0;
}

.envelope.open .env-flap {
  transform: rotateX(180deg);
  z-index: 1;
}

.envelope.open .env-card {
  transform: translateY(-74%);
}

@keyframes wobble {
  0%,
  100% {
    transform: rotate(0deg);
  }
  45% {
    transform: rotate(-1.5deg) translateY(-2px);
  }
  55% {
    transform: rotate(1.5deg) translateY(-2px);
  }
}

/* ---------------------------------------------------------------- Tờ thư */
.letter-paper {
  position: relative;
  padding: 26px 22px 84px; /* Chừa chỗ dưới cho chùm hoa góc, không che chữ ký */
  border-radius: 6px;
  background-color: #fffaf3;
  background-image: repeating-linear-gradient(0deg, transparent 0 29px, rgba(226, 85, 127, 0.1) 29px 30px),
    radial-gradient(120% 90% at 0% 0%, rgba(255, 214, 226, 0.55), transparent 55%),
    radial-gradient(120% 90% at 100% 100%, rgba(255, 220, 200, 0.45), transparent 55%);
  box-shadow: 0 24px 50px rgba(20, 5, 20, 0.45);
  color: #4a2c39;
  line-height: 1.75;
  overflow: hidden;
}

.letter-paper h2 {
  position: relative;
  margin: 18px 0 8px;
  font-family: var(--font-hand);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--rose-deep);
}

.letter-paper p {
  position: relative;
  margin: 0 0 8px;
}

.letter-paper .sign {
  margin: 10px 0 0;
  text-align: right;
  font-family: var(--font-hand);
  font-size: 1.55rem;
  color: var(--rose-deep);
}

.letter-flowers {
  position: absolute;
  width: 44%;
  pointer-events: none;
  opacity: 0.95;
}

.letter-flowers svg {
  display: block;
  width: 100%;
}

.letter-flowers.tl {
  top: -26px;
  left: -26px;
  transform: rotate(180deg) scaleX(-1);
}

.letter-flowers.br {
  right: -24px;
  bottom: -24px;
}

/* Ảnh dán bằng băng keo giấy ở góc thư */
.letter-photo {
  position: relative;
  float: right;
  width: 38%;
  margin: 6px 0 8px 12px;
  padding: 6px 6px 18px;
  background: #fff;
  box-shadow: 0 6px 14px rgba(80, 30, 50, 0.22);
  transform: rotate(4deg);
}

.letter-photo img {
  display: block;
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
}

.letter-photo .tape {
  position: absolute;
  top: -10px;
  left: 50%;
  width: 56px;
  height: 18px;
  margin-left: -28px;
  background: rgba(255, 190, 210, 0.75);
  transform: rotate(-6deg);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}