/* ==========================
   RESET
========================== */

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

html {
  scroll-behavior: smooth;
}

body {
  background: #cfd9e3;
  color: #2f3640;

  font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", sans-serif;

  overflow-x: hidden;
}

/* ==========================
   HERO
========================== */

.hero {
  position: relative;

  width: 100%;
  height: 100vh;

  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;

  width: 100%;
  height: 100%;

  object-fit: cover;

  /* 背景を少し落ち着かせる */
  filter: brightness(0.78) saturate(0.88) contrast(0.95);
}

.overlay {
  position: absolute;
  inset: 0;

  background: linear-gradient(
    rgba(255, 255, 255, 0.1),
    rgba(210, 220, 232, 0.18)
  );

  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;

  height: 100%;

  padding: 60px;
}

/* ==========================
   BRAND
========================== */

.brand {
  position: relative;
  z-index: 20;
}

.brand h1 {
  font-size: 2.8rem;

  font-weight: 300;

  letter-spacing: 0.08em;

  color: rgba(28, 34, 42, 0.95);
}

.brand p {
  margin-top: 8px;

  font-size: 0.95rem;

  letter-spacing: 0.08em;

  color: rgba(45, 50, 58, 0.72);
}

/* ==========================
   FLOATING LYRIC
========================== */

#floatingLyric {
  position: absolute;

  top: 380px;
  left: 80px;

  z-index: 9999;

  color: rgba(28, 34, 42, 0.88);

  font-size: 1rem;

  letter-spacing: 0.04em;

  opacity: 0;

  animation: lyricRise 8s linear infinite;
}

@keyframes lyricRise {
  0% {
    transform: translateY(60px);
    opacity: 0;
  }

  15% {
    opacity: 1;
  }

  75% {
    transform: translateY(-40px);
    opacity: 1;
  }

  100% {
    transform: translateY(-70px);
    opacity: 0;
  }
}

/* ==========================
   TITLE
========================== */

.title-wrap {
  position: absolute;

  top: 42%;
  left: 50%;

  transform: translate(-50%, -50%);

  text-align: center;

  transition: 1s ease;
}

.hidden {
  opacity: 0;
}

.title-wrap h2 {
  font-size: 4rem;

  font-weight: 200;

  color: rgba(22, 28, 35, 0.94);

  text-shadow: 0 2px 10px rgba(255, 255, 255, 0.35);
}

.title-wrap span {
  display: block;

  margin-top: 10px;

  font-size: 1rem;

  letter-spacing: 0.24em;

  color: rgba(45, 50, 58, 0.72);
}

/* ==========================
   TOUCH AREA
========================== */

.window-light {
  position: absolute;

  right: 10%;
  bottom: 12%;

  width: 220px;
  height: 220px;

  border-radius: 50%;

  z-index: 50;

  cursor: pointer;

  display: flex;
  justify-content: center;
  align-items: center;

  background: radial-gradient(
    rgba(255, 255, 255, 0.22),
    rgba(255, 245, 220, 0.12),
    transparent 72%
  );

  backdrop-filter: blur(2px);
}

.window-light span {
  color: rgba(25, 30, 38, 0.88);

  font-size: 0.8rem;

  font-weight: 500;

  letter-spacing: 0.08em;

  white-space: nowrap;
}

/* ==========================
   ABOUT
========================== */

.about {
  padding: 140px 10vw;

  background: linear-gradient(#d6dee7, #c6d1dd);
}

.about h3 {
  font-size: 2.4rem;

  font-weight: 300;

  color: rgba(35, 40, 48, 0.92);
}

.about-text {
  margin-top: 24px;

  font-size: 1.1rem;

  line-height: 1.8;

  color: rgba(45, 50, 58, 0.76);
}

.credit {
  margin-top: 28px;

  color: rgba(45, 50, 58, 0.48);
}

/* ==========================
   ENDING
========================== */

.ending {
  height: 70vh;

  display: flex;
  justify-content: center;
  align-items: center;

  text-align: center;

  background: linear-gradient(#c6d1dd, #eef3f7);
}

.ending-content p {
  font-size: 2rem;

  font-weight: 200;

  color: rgba(35, 40, 48, 0.88);
}

#listenAgain {
  margin-top: 24px;

  padding: 12px 28px;

  border: 1px solid rgba(40, 45, 52, 0.25);

  background: transparent;

  color: rgba(35, 40, 48, 0.82);

  cursor: pointer;
}

/* ==========================
   SIDE MENU
========================== */

.side-menu {
  position: fixed;

  top: 50%;
  right: 28px;

  transform: translateY(-50%);

  z-index: 99999;

  display: flex;
  flex-direction: column;

  gap: 18px;
}

.menu-brand {
  margin-bottom: 30px;
}

.menu-brand h3 {
  font-size: 1.2rem;

  font-weight: 300;

  color: rgba(28, 34, 42, 0.92);
}

.menu-brand p {
  margin-top: 8px;

  width: 150px;

  font-size: 0.68rem;

  line-height: 1.6;

  letter-spacing: 0.08em;

  color: rgba(45, 50, 58, 0.58);
}

.side-menu a {
  display: flex;
  align-items: center;

  gap: 12px;

  text-decoration: none;

  transition: 0.35s ease;
}

.side-menu a:hover {
  transform: translateX(-4px);
}

.story-no {
  width: 24px;

  color: rgba(45, 50, 58, 0.45);
}

.story-info {
  display: flex;
  flex-direction: column;
}

.story-info strong {
  font-size: 0.9rem;

  font-weight: 400;

  color: rgba(28, 34, 42, 0.92);
}

.story-info small {
  font-size: 0.72rem;

  color: rgba(45, 50, 58, 0.55);
}

.side-menu a.coming {
  opacity: 0.55;
}

/* ==========================
   MOBILE
========================== */

@media (max-width: 768px) {
  .hero-content {
    padding: 30px;
  }

  .title-wrap h2 {
    font-size: 2.5rem;
  }

  .window-light {
    width: 160px;
    height: 160px;
  }

  .side-menu {
    right: 10px;
  }

  .menu-brand {
    display: none;
  }

  #floatingLyric {
    top: 320px;
    left: 30px;
  }
}
/* ==========================
   HUB BACK BUTTON
========================== */

.hub-back {
  position: fixed;
  top: 20px;
  left: 20px;

  padding: 12px 20px;

  background: rgba(0, 0, 0, 0.55);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 999px;

  color: #fff;
  text-decoration: none;
  font-size: 0.9rem;
  letter-spacing: 1px;

  backdrop-filter: blur(12px);

  z-index: 9999;
  transition: all 0.3s ease;
}

.hub-back:hover {
  transform: translateY(-2px);
  border-color: rgba(255, 60, 60, 0.5);
  box-shadow: 0 0 25px rgba(255, 0, 0, 0.35);
}

/* スマホ */
@media (max-width: 768px) {
  .hub-back {
    top: 14px;
    left: 14px;
    font-size: 0.8rem;
    padding: 10px 16px;
  }
}