/* AI TOP（ai-top.html）— ダーク / ネオン / ガラスカード */

.ai-top-page {
  scroll-behavior: smooth;
  --ai-top-max: 1200px;
  --ai-top-header-h: 80px;
  --ai-top-bg: #060a14;
  --ai-top-bg-mid: #0b1224;
  --ai-top-surface: rgba(14, 20, 38, 0.72);
  --ai-top-surface-strong: rgba(18, 25, 45, 0.88);
  --ai-top-border: rgba(52, 119, 255, 0.2);
  --ai-top-border-hover: rgba(70, 140, 255, 0.45);
  --ai-top-text: #f4f7ff;
  --ai-top-muted: rgba(255, 255, 255, 0.68);
  --ai-top-subtle: rgba(255, 255, 255, 0.52);
  --ai-top-accent: #67b3ff;
  --ai-top-accent-2: #8e75ff;
  --ai-top-gold: #d4af37;
  --ai-top-radius: 18px;
  --ai-top-section-y: 56px;
  min-height: 100dvh;
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, rgba(52, 119, 255, 0.16), transparent 58%),
    radial-gradient(ellipse 45% 35% at 100% 40%, rgba(142, 117, 255, 0.1), transparent 55%),
    radial-gradient(ellipse 40% 30% at 0% 70%, rgba(52, 119, 255, 0.08), transparent 50%),
    linear-gradient(180deg, var(--ai-top-bg) 0%, var(--ai-top-bg-mid) 48%, #0a1020 100%);
  color: var(--ai-top-text);
}

/* ── Header（既存維持） ── */
.ai-top-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #071733;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.18);
}

.ai-top-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem 1.5rem;
  max-width: min(100% - 2rem, var(--ai-top-max));
  margin: 0 auto;
  min-height: var(--ai-top-header-h);
  padding: 0 16px;
  box-sizing: border-box;
}

.ai-top-header__logo {
  flex-shrink: 0;
}

.ai-top-header__nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.35rem 1.25rem;
}

.ai-top-header__nav a {
  font-size: 0.8125rem;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.88);
  text-decoration: none;
  white-space: nowrap;
}

.ai-top-header__nav a:hover {
  color: #7dd3fc;
}

.ai-top-header__cta {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 1.1rem;
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 800;
  color: #1a1a1a;
  text-decoration: none;
  background: linear-gradient(135deg, #f5e6a8, #d4af37);
  border: 1px solid rgba(212, 175, 55, 0.45);
  box-shadow: 0 4px 14px rgba(201, 162, 39, 0.22);
}

.ai-top-main {
  display: block;
}

/* ── Hero ── */
.ai-top-hero {
  position: relative;
  padding: 56px 16px 40px;
  text-align: center;
}

.ai-top-hero__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 820px;
  margin: 0 auto;
}

.ai-top-hero__badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.14em;
  color: #b8c8ff;
  background: rgba(52, 119, 255, 0.12);
  border: 1px solid rgba(103, 179, 255, 0.32);
  box-shadow: 0 0 24px rgba(52, 119, 255, 0.12);
  backdrop-filter: blur(8px);
}

.ai-top-page .neon-welcome-title {
  display: inline-block;
  margin: 0 0 16px;
  font-size: clamp(36px, 8vw, 60px);
  font-weight: 900;
  background: linear-gradient(
    90deg,
    #ffffff 0%,
    #67b3ff 30%,
    #8e75ff 65%,
    #ffffff 100%
  );
  background-size: 300% auto;
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  animation: aiTopGradient 6s linear infinite;
  letter-spacing: -0.03em;
}

@keyframes aiTopGradient {
  0% {
    background-position: 0% center;
  }
  100% {
    background-position: 300% center;
  }
}

.ai-top-hero__lead {
  margin: 0 0 28px;
  max-width: 680px;
  font-size: clamp(14px, 2vw, 16px);
  line-height: 1.75;
  color: var(--ai-top-muted);
}

.ai-top-hero__actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

.ai-top-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0 24px;
  border-radius: 14px;
  font-size: 15px;
  font-weight: 800;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}

.ai-top-btn:hover {
  transform: translateY(-1px);
}

.ai-top-btn--primary {
  color: #fff;
  background: linear-gradient(135deg, #3477ff 0%, #5b4dff 55%, #8e75ff 100%);
  border: 1px solid rgba(142, 117, 255, 0.35);
  box-shadow:
    0 0 24px rgba(52, 119, 255, 0.22),
    0 12px 32px rgba(11, 24, 53, 0.28);
}

.ai-top-btn--ghost {
  color: #dce7ff;
  background: rgba(18, 25, 45, 0.55);
  border: 1px solid rgba(52, 119, 255, 0.28);
  backdrop-filter: blur(10px);
  box-shadow: 0 0 16px rgba(52, 119, 255, 0.08);
}

.ai-top-btn--gold {
  color: #1a1a1a;
  background: linear-gradient(135deg, #f5e6a8, #d4af37);
  border: 1px solid rgba(212, 175, 55, 0.45);
  box-shadow: 0 10px 28px rgba(201, 162, 39, 0.28);
}

/* ── Feature blocks ── */
.ai-top-features {
  padding: 8px 16px var(--ai-top-section-y);
}

.ai-top-features__inner {
  display: flex;
  flex-direction: column;
  gap: 32px;
  max-width: var(--ai-top-max);
  margin: 0 auto;
}

.ai-top-feature-block__title {
  margin: 0 0 18px;
  font-size: clamp(18px, 2.4vw, 22px);
  font-weight: 800;
  line-height: 1.35;
  text-align: center;
  color: #fff;
  letter-spacing: 0.02em;
}

.ai-top-feature-block__title::after {
  content: "";
  display: block;
  width: 56px;
  height: 2px;
  margin: 10px auto 0;
  border-radius: 999px;
  background: linear-gradient(90deg, transparent, var(--ai-top-accent), var(--ai-top-accent-2), transparent);
}

.ai-top-feature-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  max-width: 920px;
  margin: 0 auto;
}

.ai-top-feature-card {
  display: block;
  text-align: left;
  text-decoration: none;
  padding: 14px 14px 12px;
  min-height: 80px;
  border-radius: var(--ai-top-radius);
  background: linear-gradient(180deg, rgba(22, 30, 52, 0.82), rgba(10, 14, 28, 0.78));
  border: 1px solid var(--ai-top-border);
  color: #fff;
  box-shadow:
    0 0 0 1px rgba(255, 255, 255, 0.03) inset,
    0 10px 28px rgba(0, 0, 0, 0.22);
  backdrop-filter: blur(12px);
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
  box-sizing: border-box;
}

.ai-top-feature-card:hover {
  transform: translateY(-2px);
  border-color: var(--ai-top-border-hover);
  box-shadow:
    0 0 0 1px rgba(103, 179, 255, 0.08) inset,
    0 0 24px rgba(52, 119, 255, 0.14),
    0 14px 32px rgba(0, 0, 0, 0.28);
}

.ai-top-feature-card__main {
  display: block;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.45;
  margin-bottom: 6px;
  color: #fff;
}

.ai-top-feature-card__sub {
  display: block;
  font-size: 11px;
  line-height: 1.5;
  color: var(--ai-top-subtle);
}

/* ── Guide（使い方 + FAQ 2カラム） ── */
.ai-top-guide {
  padding: var(--ai-top-section-y) 16px;
  border-top: 1px solid rgba(52, 119, 255, 0.1);
  background:
    radial-gradient(ellipse 60% 40% at 50% 0%, rgba(52, 119, 255, 0.08), transparent 60%),
    linear-gradient(180deg, rgba(8, 12, 24, 0.4), rgba(6, 10, 20, 0.2));
}

.ai-top-guide__inner {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  max-width: var(--ai-top-max);
  margin: 0 auto 20px;
}

.ai-top-guide__panel {
  padding: 24px 22px;
  border-radius: var(--ai-top-radius);
  background: var(--ai-top-surface);
  border: 1px solid var(--ai-top-border);
  box-shadow: 0 10px 32px rgba(0, 0, 0, 0.2);
  backdrop-filter: blur(14px);
}

.ai-top-guide__heading {
  margin: 0 0 18px;
  font-size: clamp(18px, 2.2vw, 21px);
  font-weight: 800;
  line-height: 1.35;
  color: #fff;
}

.ai-top-guide-steps {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.ai-top-guide-step {
  padding: 14px 14px 12px;
  border-radius: 14px;
  background: var(--ai-top-surface-strong);
  border: 1px solid rgba(52, 119, 255, 0.14);
}

.ai-top-guide-step__label {
  display: inline-block;
  margin-bottom: 6px;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.1em;
  color: var(--ai-top-accent);
}

.ai-top-guide-step__title {
  display: block;
  margin-bottom: 6px;
  font-size: 15px;
  font-weight: 800;
  color: #fff;
}

.ai-top-guide-step__text {
  margin: 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--ai-top-muted);
}

.ai-top-faq__list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.ai-top-faq__item {
  border-radius: 14px;
  background: var(--ai-top-surface-strong);
  border: 1px solid rgba(52, 119, 255, 0.14);
  overflow: hidden;
}

.ai-top-faq__item summary {
  padding: 14px 16px;
  font-size: 14px;
  font-weight: 800;
  color: #fff;
  cursor: pointer;
  list-style: none;
}

.ai-top-faq__item summary::-webkit-details-marker {
  display: none;
}

.ai-top-faq__item summary::after {
  content: "+";
  float: right;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--ai-top-accent);
}

.ai-top-faq__item[open] summary::after {
  content: "−";
}

.ai-top-faq__answer {
  padding: 0 16px 14px;
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--ai-top-muted);
}

/* ── Notice（統合） ── */
.ai-top-notice__inner {
  max-width: var(--ai-top-max);
  margin: 0 auto;
  padding: 18px 20px;
  border-radius: var(--ai-top-radius);
  background: rgba(10, 14, 28, 0.55);
  border: 1px solid rgba(52, 119, 255, 0.12);
}

.ai-top-notice__title {
  margin: 0 0 10px;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: rgba(255, 255, 255, 0.82);
}

.ai-top-notice__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.ai-top-notice__list li {
  position: relative;
  padding-left: 1.1em;
  font-size: 12px;
  line-height: 1.65;
  color: var(--ai-top-subtle);
}

.ai-top-notice__list li + li {
  margin-top: 6px;
}

.ai-top-notice__list li::before {
  content: "・";
  position: absolute;
  left: 0;
  color: var(--ai-top-accent);
  font-weight: 800;
}

/* ── Bottom CTA ── */
.ai-top-cta-bottom {
  padding: 52px 16px 64px;
  text-align: center;
  background:
    radial-gradient(ellipse 70% 55% at 50% 100%, rgba(52, 119, 255, 0.16), transparent 58%),
    radial-gradient(ellipse 50% 40% at 0% 0%, rgba(142, 117, 255, 0.1), transparent 50%),
    linear-gradient(180deg, rgba(10, 16, 32, 0.5) 0%, #060a14 100%);
  border-top: 1px solid rgba(52, 119, 255, 0.1);
}

.ai-top-cta-bottom__inner {
  max-width: 720px;
  margin: 0 auto;
}

.ai-top-cta-bottom__title {
  margin: 0 0 12px;
  font-size: clamp(22px, 2.8vw, 30px);
  font-weight: 900;
  line-height: 1.35;
  color: #fff;
}

.ai-top-cta-bottom__lead {
  margin: 0 auto 24px;
  max-width: 36em;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ai-top-muted);
}

/* ── Responsive ── */
@media (max-width: 900px) {
  .ai-top-page {
    --ai-top-section-y: 36px;
  }

  .ai-top-hero {
    padding: 40px 16px 28px;
  }

  .ai-top-hero__lead br {
    display: none;
  }

  .ai-top-features__inner {
    gap: 20px;
  }

  .ai-top-feature-block__title {
    margin-bottom: 10px;
    font-size: 17px;
  }

  .ai-top-feature-grid {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .ai-top-feature-card {
    min-height: 0;
    padding: 10px 12px 8px;
  }

  .ai-top-feature-card__main {
    font-size: 14px;
    margin-bottom: 4px;
  }

  .ai-top-feature-card__sub {
    font-size: 10px;
  }

  .ai-top-guide__inner {
    grid-template-columns: 1fr;
    gap: 12px;
    margin-bottom: 12px;
  }

  .ai-top-guide__panel {
    padding: 16px 14px;
  }

  .ai-top-guide__panel--steps .ai-top-guide__heading {
    margin-bottom: 12px;
  }

  .ai-top-guide-steps {
    gap: 6px;
  }

  .ai-top-guide-step {
    padding: 8px 10px;
  }

  .ai-top-guide-step__title {
    font-size: 14px;
  }

  .ai-top-guide-step__text {
    font-size: 12px;
  }

  .ai-top-faq__list {
    gap: 8px;
  }

  .ai-top-faq__item summary {
    padding: 12px 14px;
  }

  .ai-top-faq__answer {
    padding: 0 14px 12px;
  }

  .ai-top-notice__inner {
    padding: 12px 14px;
  }

  .ai-top-notice__title {
    margin-bottom: 6px;
  }

  .ai-top-notice__list li + li {
    margin-top: 4px;
  }

  .ai-top-cta-bottom {
    padding: 40px 16px 48px;
  }
}

@media (max-width: 768px) {
  .ai-top-header__nav {
    display: none;
  }

  .ai-top-header__inner {
    min-height: 64px;
  }

  .ai-top-header__cta {
    min-height: 38px;
    padding: 0 0.9rem;
    font-size: 0;
    line-height: 0;
  }

  .ai-top-header__cta::after {
    content: "はじめる";
    font-size: 0.8125rem;
    font-weight: 800;
    line-height: 1;
    color: #1a1a1a;
  }
}