:root {
  --pirelli-yellow: #fed100;
  --pirelli-dark: #111111;
  --pirelli-red: #e30613;
}

html {
  scroll-behavior: smooth;
}

/* ===== Hero Slider ===== */
.hero-slider {
  position: relative;
  overflow: hidden;
}
.hero-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 1s ease-in-out;
  background-size: cover;
  background-position: center;
}
.hero-slide.active {
  opacity: 1;
}
.hero-overlay {
  background: linear-gradient(
    90deg,
    rgba(17, 17, 17, 0.85) 0%,
    rgba(17, 17, 17, 0.55) 45%,
    rgba(17, 17, 17, 0.15) 100%
  );
}

/* slide nav dots */
.hero-dot {
  width: 38px;
  height: 5px;
  background: rgba(255, 255, 255, 0.4);
  transition: background 0.3s;
  cursor: pointer;
}
.hero-dot.active {
  background: var(--pirelli-yellow);
}

/* ===== Diagonal accent ===== */
.skew-tag {
  transform: skewX(-12deg);
}
.skew-tag > span {
  display: inline-block;
  transform: skewX(12deg);
}

/* ===== Logo ===== */
.logo-badge {
  line-height: 1;
}

/* ===== Section title ===== */
.section-title-en {
  font-family: 'Oswald', sans-serif;
  letter-spacing: 0.15em;
  color: var(--pirelli-yellow);
}

/* ===== Cards hover ===== */
.lift {
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.lift:hover {
  transform: translateY(-6px);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.15);
}

/* tire spin deco */
@keyframes spin-slow {
  to {
    transform: rotate(360deg);
  }
}
.spin-slow {
  animation: spin-slow 14s linear infinite;
}

/* fade in on scroll */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* racing stripe (pirelli yellow x red) */
.race-stripe {
  background-image: repeating-linear-gradient(
    45deg,
    var(--pirelli-yellow) 0,
    var(--pirelli-yellow) 14px,
    var(--pirelli-red) 14px,
    var(--pirelli-red) 28px
  );
}

/* スクリーンリーダー専用（SEO用見出し等） */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}