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

:root {
  --bg:          #0a0806;
  --gold:        #c9a84c;
  --gold-dim:    #7a6030;
  --text:        #c4b49a;
  --text-dim:    #6a5a45;
  --text-bright: #e8dcc8;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Noto Serif JP', 'Georgia', serif;
  overflow-x: hidden;
}

/* ===== フルスクリーンヒーロー ===== */
.welcome-hero {
  position: relative;
  width: 100%;
  height: 100svh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-image: url('images/interior.png');
  background-size: cover;
  background-position: center 30%;
  animation: slow-zoom 20s ease-out forwards;
}

@keyframes slow-zoom {
  from { transform: scale(1.06); }
  to   { transform: scale(1.0); }
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(to bottom,
      rgba(10,8,6,0.50) 0%,
      rgba(10,8,6,0.20) 40%,
      rgba(10,8,6,0.50) 70%,
      rgba(10,8,6,0.92) 100%
    );
}

.hero-content {
  position: relative;
  z-index: 10;
  text-align: center;
  padding: 2rem;
  animation: fade-up 1.8s ease both;
  animation-delay: 0.4s;
}

@keyframes fade-up {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}

.welcome-logo {
  width: clamp(260px, 45vw, 480px);
  margin-bottom: 1.5rem;
  display: block;
}

.welcome-title {
  font-family: 'Noto Serif JP', serif;
  font-size: clamp(0.85rem, 1.5vw, 1rem);
  font-weight: 300;
  color: var(--text-bright);
  line-height: 2;
  letter-spacing: 0.1em;
  text-shadow: 0 2px 40px rgba(0,0,0,0.9);
}

/* スクロールヒント */
.scroll-hint {
  position: absolute;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
  animation: fade-up 2s ease both;
  animation-delay: 1.8s;
}

.scroll-hint span {
  font-size: 0.6rem;
  letter-spacing: 0.35em;
  color: var(--text-dim);
  text-transform: uppercase;
}

.scroll-line {
  width: 1px;
  height: 44px;
  background: linear-gradient(to bottom, var(--text-dim), transparent);
  animation: scroll-pulse 2.2s ease-in-out infinite;
}

@keyframes scroll-pulse {
  0%, 100% { opacity: 0.35; transform: scaleY(1) translateY(0); }
  50%       { opacity: 0.9;  transform: scaleY(0.5) translateY(10px); }
}

/* ===== コンセプトセクション ===== */
.concept {
  background: var(--bg);
  position: relative;
}

.concept::before {
  content: '';
  display: block;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--gold-dim), transparent);
  margin: 0 auto;
  max-width: 360px;
}

.concept-inner {
  max-width: 660px;
  margin: 0 auto;
  padding: 8rem 2rem 6rem;
}

/* スクロールアニメーション */
.concept-block,
.concept-enter {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 1s ease, transform 1s ease;
  margin-bottom: 3.5rem;
}

.concept-block.visible,
.concept-enter.visible {
  opacity: 1;
  transform: translateY(0);
}

.concept-block p {
  font-size: clamp(0.88rem, 1.7vw, 1.02rem);
  line-height: 2.3;
  color: var(--text);
  letter-spacing: 0.07em;
}

.concept-fragments p {
  line-height: 2.7;
  color: var(--text-dim);
  font-size: clamp(0.84rem, 1.5vw, 0.97rem);
}

.concept-mid p {
  line-height: 2.5;
}

.concept-keywords p {
  font-family: 'Cormorant Garamond', serif;
  font-style: italic;
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-dim);
  letter-spacing: 0.12em;
}

.concept-closing p {
  font-size: clamp(0.95rem, 1.9vw, 1.1rem);
  line-height: 2.5;
  color: var(--text-bright);
  letter-spacing: 0.08em;
}

/* ===== 展示室へボタン ===== */
.concept-enter {
  display: flex;
  justify-content: center;
  padding-top: 2rem;
  margin-bottom: 0;
}

.btn-enter {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 0.8rem;
  text-decoration: none;
  color: var(--gold);
  font-size: 0.82rem;
  letter-spacing: 0.35em;
  font-family: 'Noto Serif JP', serif;
  transition: color 0.4s;
  outline: none;
}

.btn-enter:hover {
  color: #e8c97a;
}

.btn-enter-line {
  display: block;
  width: 1px;
  height: 52px;
  background: linear-gradient(to bottom, var(--gold-dim), transparent);
  transition: height 0.4s ease;
}

.btn-enter:hover .btn-enter-line {
  height: 72px;
}

/* ===== フッター ===== */
.welcome-footer {
  text-align: center;
  padding: 2.5rem;
  border-top: 1px solid #141008;
}

.welcome-footer p {
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  color: #221a0e;
}

/* ===== レスポンシブ ===== */
@media (max-width: 640px) {
  .welcome-title {
    line-height: 2.2;
  }
  .concept-inner {
    padding: 5rem 1.5rem 4rem;
  }
}