:root {
  --paper: #efe3cb;
  --ink: #1f1c19;
  --white: #fffaf1;
  --line: rgba(31, 28, 25, 0.35);
  --red: #a80212;
  --font-mincho: "Hina Mincho", "Yu Mincho", serif;
  --font-gothic: "Zen Kaku Gothic New", system-ui, sans-serif;
  --font-old: "Zen Old Mincho", "Yu Mincho", serif;
  --font-script: "Italianno", cursive;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: #0f0f0f;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-gothic);
  letter-spacing: 0;
  background: #0f0f0f;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  font: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  display: flex;
  justify-content: center;
  background: #0d0d0d;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(100%, 750px);
  height: 58px;
  padding: 0 18px;
}

.site-logo {
  width: 86px;
  height: auto;
}

.login-button {
  min-width: 132px;
  height: 31px;
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: 999px;
}

.sl-page {
  position: relative;
  width: min(100%, 750px);
  margin: 0 auto;
  overflow: hidden;
  background-color: var(--paper);
  background-image:
    linear-gradient(rgba(255, 250, 241, 0.28), rgba(255, 250, 241, 0.28)),
    url("https://web.familyclub.jp/files/53/jwb/freepage/sixtones_letters/assets/images/common/bg__main-container@2x.webp");
  background-repeat: repeat-y;
  background-size: 100% auto;
  box-shadow: 0 0 48px rgba(0, 0, 0, 0.32);
}

.fv {
  position: relative;
  aspect-ratio: 15 / 28;
  min-height: calc(100svh - 58px);
  overflow: hidden;
}

.fv__inner {
  position: relative;
  height: 100%;
}

.light-field {
  position: absolute;
  inset: 0;
  opacity: 0.28;
  background:
    radial-gradient(circle at 20% 16%, rgba(255, 252, 231, 0.8), transparent 18%),
    radial-gradient(circle at 82% 72%, rgba(214, 178, 95, 0.45), transparent 24%),
    radial-gradient(circle at 45% 92%, rgba(255, 255, 255, 0.5), transparent 18%);
  filter: blur(2px);
  animation: lightDrift 10s ease-in-out infinite alternate;
}

.fv__logo {
  position: absolute;
  top: 16.2%;
  left: 50%;
  z-index: 3;
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 77%;
  transform: translateX(-50%);
}

.fv__logo img {
  display: block;
  height: auto;
}

.stamp {
  width: 74%;
  margin-left: 33%;
  opacity: 0;
  transform: translateY(-18px) scale(1.18);
  animation: stampIn 1.35s cubic-bezier(0.2, 0.95, 0.2, 1) 0.1s forwards;
}

.type {
  opacity: 0;
  clip-path: inset(0 100% 0 0);
  transform: scale(0.97);
  animation: writeIn 1.9s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.type-ja-1 {
  width: 92.5%;
  margin-top: 5.3%;
  animation-delay: 0.62s;
}

.type-en {
  width: 81.4%;
  margin-top: 5.8%;
  animation-delay: 1.1s;
}

.type-ja-2 {
  width: 47.6%;
  margin-top: 6.9%;
  animation-delay: 0.92s;
}

.letter {
  position: absolute;
  z-index: 2;
  display: block;
  height: auto;
  opacity: 0;
  filter: blur(12px);
  transform: scale(1.1);
  animation: letterIn 1.25s cubic-bezier(0.16, 1, 0.3, 1) 2.35s forwards;
}

.letter-pink {
  top: -4%;
  left: -29%;
  width: 64%;
  --x: -48px;
  --y: -32px;
}

.letter-green {
  top: -10.1%;
  left: 19.4%;
  width: 66%;
  --x: 0;
  --y: -32px;
}

.letter-yellow {
  top: -0.5%;
  right: -24.5%;
  width: 64%;
  --x: 48px;
  --y: -32px;
}

.letter-black {
  bottom: 4.5%;
  left: -29.6%;
  width: 66%;
  --x: -48px;
  --y: 32px;
}

.letter-blue {
  bottom: 9.2%;
  left: 18.9%;
  width: 64%;
  --x: 0;
  --y: 32px;
}

.letter-red {
  right: -24.5%;
  bottom: 11.8%;
  width: 66%;
  --x: 48px;
  --y: 32px;
}

.scroll-button {
  position: absolute;
  right: 9px;
  bottom: 46px;
  z-index: 6;
  display: grid;
  place-items: center;
  width: 80px;
  height: 80px;
  color: #fff;
  text-decoration: none;
  background-image: url("https://web.familyclub.jp/files/53/jwb/freepage/sixtones_letters/assets/images/common/bg__share-button@2x.webp");
  background-size: cover;
  border-radius: 50%;
  opacity: 0;
  transform: translateY(12px);
  animation: fadeRise 1.1s ease 3.3s forwards;
}

.scroll-button span {
  margin-top: 7px;
  font-family: var(--font-old);
  font-size: 10px;
  font-weight: 700;
  line-height: 1;
}

.scroll-button svg {
  width: 5px;
  margin-top: -9px;
  fill: currentColor;
  transform: rotate(90deg);
}

.section-pad {
  position: relative;
  padding: 64px 24px;
}

.section-inner {
  position: relative;
  z-index: 2;
  max-width: 560px;
  margin: 0 auto;
}

.section-title {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: center;
  margin: 0 0 30px;
}

.section-title img {
  width: 194px;
  height: auto;
}

.section-title span {
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.05em;
}

.concept-card {
  position: relative;
  padding: 50px 32px 36px;
  background: rgba(255, 255, 255, 0.08);
  border: 2.5px solid rgba(255, 255, 255, 0.9);
}

.concept-card::before,
.concept-card::after {
  position: absolute;
  width: 52px;
  height: 1px;
  content: "";
  background: rgba(31, 28, 25, 0.65);
  transform: rotate(-45deg);
}

.concept-card::before {
  top: 26px;
  left: -11px;
}

.concept-card::after {
  right: -11px;
  bottom: 26px;
}

.concept-copy {
  display: flex;
  flex-direction: column;
  gap: 31px;
}

.concept-copy p {
  margin: 0;
  font-family: var(--font-mincho);
  font-size: 13px;
  font-style: italic;
  line-height: 2.15;
  letter-spacing: 0.15em;
}

.concept-sign {
  display: block;
  width: 137px;
  margin: 39px 12px 0 auto;
}

.publish-note {
  margin: 0;
  padding: 0 20px 24px;
  font-size: 12px;
  font-weight: 700;
  text-align: center;
  letter-spacing: 0.04em;
}

.anchor-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  min-height: 110px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.anchor-grid a {
  display: grid;
  place-items: center;
  border-left: 1px solid var(--line);
  transition: opacity 0.25s ease;
}

.anchor-grid a:first-child {
  border-left: 0;
}

.anchor-grid a:hover {
  opacity: 0.45;
}

.anchor-grid img {
  display: block;
  width: auto;
  max-width: 64px;
  height: 72px;
}

.letter-section {
  overflow: hidden;
  padding-top: 72px;
  padding-bottom: 70px;
}

.loop-text {
  position: absolute;
  top: 38px;
  left: 0;
  z-index: 0;
  width: 100%;
  overflow: hidden;
  opacity: 0.78;
}

.loop-text__track {
  display: flex;
  width: max-content;
  animation: loopText 34s linear infinite;
}

.loop-text__track.slow {
  animation-duration: 42s;
}

.loop-text img {
  width: auto;
  height: 84px;
  flex: 0 0 auto;
}

.letter-title {
  width: min(100%, 476px);
  margin: 0 auto 48px;
  text-align: center;
}

.letter-title img {
  width: 100%;
  height: auto;
}

.muted-title {
  opacity: 0.32;
}

.letter-pair {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
  align-items: start;
}

.letter-item {
  min-width: 0;
}

.letter-open {
  position: relative;
  display: block;
  width: 100%;
  padding: 0;
  cursor: pointer;
  background: transparent;
  border: 0;
}

.letter-open img {
  display: block;
  width: 100%;
  height: auto;
  filter: drop-shadow(0 16px 18px rgba(74, 52, 29, 0.18));
  transition: transform 0.45s cubic-bezier(0.16, 1, 0.3, 1);
}

.letter-open:hover img {
  transform: translateY(-7px) rotate(-1deg);
}

.detail-orbit {
  position: absolute;
  right: 5%;
  bottom: 13%;
  display: grid;
  place-items: center;
  width: 64px;
  height: 64px;
  color: #fff;
  font-family: var(--font-script);
  font-size: 19px;
  line-height: 0.9;
  background: var(--red);
  border-radius: 50%;
  box-shadow: 0 7px 18px rgba(168, 2, 18, 0.22);
}

.detail-arrow {
  position: absolute;
  right: 15.5%;
  bottom: 18.5%;
  width: 9px;
  height: 9px;
  border-top: 1px solid #fff;
  border-right: 1px solid #fff;
  transform: rotate(45deg);
}

.is-coming .letter-open {
  cursor: default;
}

.is-coming .letter-open img {
  opacity: 0.42;
  filter: grayscale(0.15) drop-shadow(0 12px 16px rgba(74, 52, 29, 0.13));
}

.coming-over {
  position: absolute;
  inset: 0;
  z-index: 2;
  display: grid;
  place-items: center;
  color: var(--ink);
  font-family: var(--font-script);
  font-size: 27px;
  line-height: 0.92;
  text-align: center;
  transform: rotate(-6deg);
}

.coming-over strong {
  font-size: 1.32em;
  font-weight: 400;
}

.letter-links {
  display: grid;
  gap: 12px;
  margin-top: 22px;
}

.letter-link-head {
  position: relative;
  min-height: 46px;
  padding-top: 19px;
  font-size: 11px;
  font-weight: 700;
  line-height: 1.55;
  letter-spacing: 0.04em;
}

.letter-link-head::before {
  position: absolute;
  top: 0;
  left: 0;
  width: 108px;
  height: 11px;
  content: "IMPRESSIONS";
  font-family: var(--font-old);
  font-size: 8px;
  letter-spacing: 0.14em;
  opacity: 0.65;
}

.small-pill {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 40px;
  color: var(--ink);
  font-size: 9.5px;
  font-weight: 700;
  letter-spacing: 0.04em;
  background-image: url("https://web.familyclub.jp/files/53/jwb/freepage/sixtones_letters/assets/images/common/bg__button@2x.webp");
  background-size: 100% 100%;
  border: 1px solid var(--ink);
  border-radius: 999px;
}

.small-pill::after {
  position: absolute;
  right: 12px;
  width: 7px;
  height: 7px;
  content: "";
  border-top: 1px solid currentColor;
  border-right: 1px solid currentColor;
  transform: rotate(45deg);
}

.small-pill.muted {
  font-family: var(--font-script);
  font-size: 19px;
  font-weight: 400;
  opacity: 0.5;
}

.is-coming-section {
  min-height: 420px;
  border-top: 1px dashed rgba(31, 28, 25, 0.28);
}

.month-coming {
  display: block;
  width: 180px;
  margin: 42px auto 0;
  opacity: 0.5;
}

.outro {
  display: grid;
  gap: 36px;
  justify-items: center;
  padding-bottom: 72px;
}

.blog-banner {
  display: block;
  width: min(100%, 324px);
}

.blog-banner img {
  display: block;
  width: 100%;
  height: auto;
}

.share {
  display: grid;
  gap: 14px;
  justify-items: center;
  text-align: center;
}

.share img {
  width: 82px;
}

.share p {
  margin: 0;
  font-size: 12px;
  font-weight: 700;
}

.share-buttons {
  display: flex;
  gap: 14px;
}

.share-buttons button,
.top-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 112px;
  height: 42px;
  color: var(--ink);
  font-size: 11px;
  font-weight: 700;
  text-decoration: none;
  background: transparent;
  border: 1px solid var(--ink);
  border-radius: 999px;
}

.letter-modal {
  width: min(100%, 750px);
  max-width: none;
  height: 100dvh;
  max-height: none;
  padding: 0;
  color: var(--ink);
  background: transparent;
  border: 0;
}

.letter-modal::backdrop {
  background: rgba(0, 0, 0, 0.35);
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(255, 250, 241, 0.92);
}

.modal-card {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 100%;
  padding: 40px 18px;
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  z-index: 5;
  width: 38px;
  height: 38px;
  cursor: pointer;
  background: rgba(31, 28, 25, 0.75);
  border: 0;
  border-radius: 50%;
}

.modal-close::before,
.modal-close::after {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 17px;
  height: 1px;
  content: "";
  background: #fff;
}

.modal-close::before {
  transform: translate(-50%, -50%) rotate(45deg);
}

.modal-close::after {
  transform: translate(-50%, -50%) rotate(-45deg);
}

.modal-envelope {
  position: relative;
  width: min(100%, 440px);
  height: min(72dvh, 620px);
  perspective: 1200px;
}

.modal-flap {
  position: absolute;
  inset: 0;
  z-index: 2;
  background:
    linear-gradient(140deg, rgba(255, 252, 238, 0.2), rgba(205, 171, 118, 0.15)),
    url("https://web.familyclub.jp/files/53/jwb/freepage/sixtones_letters/assets/images/common/member/jesse/img__letter@3x.webp") center / contain no-repeat;
  transform-origin: top center;
  filter: drop-shadow(0 16px 24px rgba(92, 60, 26, 0.2));
  animation: flapOpen 1.15s ease 0.2s forwards;
}

.modal-paper {
  position: absolute;
  inset: 7% 8% 4%;
  padding: 46px 30px 32px;
  overflow: hidden auto;
  background:
    linear-gradient(rgba(255, 250, 241, 0.8), rgba(255, 250, 241, 0.8)),
    url("https://web.familyclub.jp/files/53/jwb/freepage/sixtones_letters/assets/images/letters/backumber-detail/bg__backumber@2x.webp") center top / cover;
  border: 1px solid rgba(31, 28, 25, 0.12);
  box-shadow: 0 20px 38px rgba(70, 48, 23, 0.22);
  opacity: 0;
  transform: translateY(28%);
  animation: paperUp 1.15s cubic-bezier(0.16, 1, 0.3, 1) 0.85s forwards;
}

.modal-kicker {
  margin: 0 0 12px;
  font-family: var(--font-old);
  font-size: 10px;
  letter-spacing: 0.2em;
}

.modal-paper h3 {
  margin: 0 0 28px;
  font-family: var(--font-mincho);
  font-size: 23px;
  font-style: italic;
  font-weight: 400;
  letter-spacing: 0.1em;
}

.modal-copy {
  display: grid;
  gap: 18px;
}

.modal-copy p {
  margin: 0;
  font-family: var(--font-mincho);
  font-size: 15px;
  font-style: italic;
  line-height: 2.05;
  letter-spacing: 0.12em;
}

.voice-button {
  display: grid;
  place-items: center;
  width: 72px;
  height: 72px;
  margin: 32px 0 0 auto;
  color: #fff;
  font-family: var(--font-script);
  font-size: 24px;
  background: var(--red);
  border: 0;
  border-radius: 50%;
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity 0.9s ease,
    transform 1.1s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.is-in {
  opacity: 1;
  transform: translateY(0);
}

@keyframes stampIn {
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes writeIn {
  to {
    opacity: 1;
    clip-path: inset(0 0 0 0);
    transform: scale(1);
  }
}

@keyframes letterIn {
  from {
    transform: translate(var(--x), var(--y)) scale(1.1);
  }
  to {
    opacity: 1;
    filter: blur(0);
    transform: translate(0, 0) scale(1);
  }
}

@keyframes fadeRise {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes loopText {
  to {
    transform: translateX(-50%);
  }
}

@keyframes lightDrift {
  to {
    transform: translate3d(0, -18px, 0) scale(1.05);
  }
}

@keyframes flapOpen {
  to {
    opacity: 0.25;
    transform: rotateX(78deg) translateY(-24px);
  }
}

@keyframes paperUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 520px) {
  .site-header__inner {
    height: 54px;
  }

  .fv {
    min-height: calc(100svh - 54px);
  }

  .section-pad {
    padding-right: 20px;
    padding-left: 20px;
  }

  .concept-card {
    padding-right: 22px;
    padding-left: 28px;
  }

  .letter-pair {
    gap: 16px;
  }

  .letter-link-head {
    font-size: 10px;
  }

  .small-pill {
    height: 38px;
  }
}

@media (max-width: 374px) {
  .section-pad {
    padding-right: 14px;
    padding-left: 14px;
  }

  .concept-copy p {
    font-size: 12.5px;
  }

  .letter-pair {
    gap: 12px;
  }

  .detail-orbit {
    width: 56px;
    height: 56px;
    font-size: 17px;
  }
}