/* 2026-09-13: 清潔感・きれいめな印象にするため、ダークテーマからライトテーマに変更 */
:root {
  --color-bg: #f6f8fc;
  --color-bg-alt: #ffffff;
  --color-surface: #ffffff;
  --color-text: #1b2333;
  --color-text-muted: #5c657a;
  --color-accent: #4f6df5;
  --color-accent-2: #a855f7;
  --color-border: #e3e7f0;
  --shadow-soft: 0 1px 3px rgba(20, 30, 60, 0.06), 0 10px 28px rgba(20, 30, 60, 0.06);
  --radius: 14px;
  --max-width: 1080px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: "Hiragino Sans", "Noto Sans JP", "Segoe UI", sans-serif;
  line-height: 1.7;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding-inline: 20px;
}

a { color: inherit; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 14px;
}

.logo {
  font-weight: 700;
  text-decoration: none;
  font-size: 1.05rem;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 0.92rem;
}

.main-nav a {
  text-decoration: none;
  color: var(--color-text-muted);
}
.main-nav a:hover { color: var(--color-text); }

.nav-cta {
  padding: 8px 16px;
  border-radius: 999px;
  background: var(--color-accent);
  color: #0b0e14 !important;
  font-weight: 600;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--color-text);
}

/* Hero */
.hero {
  position: relative;
  min-height: 78vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: radial-gradient(ellipse at 70% 15%, rgba(79,109,245,0.14), transparent 60%),
              radial-gradient(ellipse at 15% 85%, rgba(168,85,247,0.10), transparent 55%),
              var(--color-bg);
}

#heroCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  padding-block: 80px;
  max-width: 720px;
}

.eyebrow {
  color: var(--color-accent);
  font-weight: 600;
  letter-spacing: 0.04em;
  margin-bottom: 12px;
}

.hero h1 {
  font-size: clamp(1.8rem, 4.2vw, 2.8rem);
  line-height: 1.35;
  margin: 0 0 20px;
}

.hero-lead {
  color: var(--color-text-muted);
  font-size: 1.02rem;
  max-width: 560px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  margin-top: 32px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 13px 26px;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.15s ease, opacity 0.15s ease;
}
.btn:hover { transform: translateY(-1px); }

.btn-primary {
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
  color: #0b0e14;
}

.btn-ghost {
  border: 1px solid var(--color-border);
  color: var(--color-text);
}

/* Sections */
.section { padding-block: 72px; }
.section-alt { background: var(--color-bg-alt); }

.section h2 {
  font-size: clamp(1.4rem, 2.6vw, 1.9rem);
  margin-bottom: 12px;
}

.section-lead {
  color: var(--color-text-muted);
  max-width: 640px;
  margin-bottom: 36px;
}

.grid { display: grid; gap: 20px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-soft);
}
.card h3 { margin-top: 0; font-size: 1.05rem; }
.card p { color: var(--color-text-muted); margin-bottom: 0; }

.card-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
  opacity: 0.9;
  overflow: hidden;
}
.card-icon img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.curriculum-visual {
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 24px;
  max-width: 640px;
  aspect-ratio: 3 / 2;
  background: linear-gradient(135deg, rgba(79,109,245,0.18), rgba(168,85,247,0.14));
}
.curriculum-visual img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.disclaimer {
  margin-top: 32px;
  font-size: 0.82rem;
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-border);
  padding-top: 20px;
}

/* Curriculum */
.curriculum-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 10px;
}
.curriculum-list li {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 14px 18px;
  display: flex;
  gap: 16px;
  align-items: baseline;
  box-shadow: var(--shadow-soft);
}
.curriculum-list .day {
  color: var(--color-accent);
  font-weight: 700;
  min-width: 56px;
  flex-shrink: 0;
}

/* Instructor */
.instructor-wrap {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 32px;
  align-items: center;
}
.instructor-photo {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
  opacity: 0.85;
  overflow: hidden;
  flex-shrink: 0;
}
.instructor-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* FAQ */
.faq-list { display: grid; gap: 10px; max-width: 720px; }
.faq-list details {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 14px 18px;
  box-shadow: var(--shadow-soft);
}
.faq-list summary {
  cursor: pointer;
  font-weight: 600;
}
.faq-list p {
  color: var(--color-text-muted);
  margin: 10px 0 0;
}

/* Contact form */
.contact-form {
  max-width: 520px;
  display: grid;
  gap: 16px;
}
.contact-form label {
  display: grid;
  gap: 6px;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
.contact-form input,
.contact-form textarea {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 11px 14px;
  color: var(--color-text);
  font-family: inherit;
  font-size: 0.95rem;
}
.contact-form input:focus,
.contact-form textarea:focus {
  outline: 2px solid var(--color-accent);
}
.btn-submit {
  border: none;
  cursor: pointer;
  justify-self: start;
}
.form-status {
  min-height: 1.2em;
  font-size: 0.9rem;
}
.form-status.success { color: #178a4c; }
.form-status.error { color: #d3352f; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding-block: 28px;
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

/* Scroll reveal */
[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive */
@media (max-width: 780px) {
  .main-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    align-items: flex-start;
    padding: 16px 20px;
    display: none;
    gap: 14px;
  }
  .main-nav.is-open { display: flex; }
  .nav-toggle { display: flex; }
  .grid-3 { grid-template-columns: 1fr; }
  .instructor-wrap { grid-template-columns: 1fr; text-align: left; }
  .instructor-photo { width: 96px; height: 96px; }
  /* 幅が狭いとテキストと重なり読みにくくなるため、モバイルでは3D演出を非表示にする */
  #heroCanvas { display: none; }
}