/* =============================================
   リセット & ベーススタイル
   ============================================= */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --color-bg: #f8f9fc;
  --color-bg-alt: #ffffff;
  --color-surface: #ffffff;
  --color-border: #e2e8f0;
  --color-text: #1a202c;
  --color-text-muted: #64748b;
  --color-accent: #2563eb;
  --color-accent-light: #dbeafe;
  --color-accent-hover: #1d4ed8;
  --color-tag-bg: #eff6ff;
  --color-tag-text: #1e40af;
  --radius: 12px;
  --radius-sm: 6px;
  --shadow: 0 1px 3px rgba(0,0,0,.07), 0 4px 16px rgba(0,0,0,.06);
  --shadow-hover: 0 4px 12px rgba(37,99,235,.15), 0 8px 32px rgba(0,0,0,.10);
  --transition: 0.25s ease;
  --font-sans: 'Inter', 'Noto Sans JP', sans-serif;
  --nav-height: 64px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover { color: var(--color-accent-hover); }

img { max-width: 100%; display: block; }

/* =============================================
   ナビゲーション
   ============================================= */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 100;
  background: rgba(248,249,252,.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition), box-shadow var(--transition);
}

#navbar.scrolled {
  background: rgba(255,255,255,.95);
  box-shadow: var(--shadow);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text);
  letter-spacing: -.02em;
}

.nav-logo:hover { color: var(--color-accent); }

.nav-links {
  display: flex;
  list-style: none;
  gap: 32px;
}

.nav-links a {
  font-size: .9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.nav-links a:hover,
.nav-links a.active { color: var(--color-accent); }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* モバイルメニュー */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  z-index: 99;
  box-shadow: var(--shadow);
}

.mobile-menu ul {
  list-style: none;
  padding: 16px 0;
}

.mobile-menu a {
  display: block;
  padding: 12px 24px;
  color: var(--color-text);
  font-weight: 500;
  transition: background var(--transition), color var(--transition);
}

.mobile-menu a:hover {
  background: var(--color-accent-light);
  color: var(--color-accent);
}

.mobile-menu.open { display: block; }

/* =============================================
   ヒーローセクション
   ============================================= */
#hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: calc(var(--nav-height) + 60px) 24px 80px;
  background: linear-gradient(135deg, #f0f4ff 0%, #fafbff 50%, #f8f9fc 100%);
  position: relative;
  overflow: hidden;
}

#hero::before {
  content: '';
  position: absolute;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(37,99,235,.06) 0%, transparent 70%);
  top: -100px;
  right: -100px;
  pointer-events: none;
}

#hero::after {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(99,102,241,.05) 0%, transparent 70%);
  bottom: 0;
  left: -50px;
  pointer-events: none;
}

.hero-content {
  text-align: center;
  max-width: 700px;
  position: relative;
  z-index: 1;
}

.hero-greeting {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin-bottom: 8px;
  font-weight: 400;
}

.hero-name {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  letter-spacing: -.04em;
  color: var(--color-text);
  margin-bottom: 16px;
  line-height: 1.1;
}

.hero-tagline {
  font-size: clamp(.95rem, 2vw, 1.1rem);
  color: var(--color-text-muted);
  margin-bottom: 24px;
  line-height: 1.8;
}

.hero-tagline .accent {
  color: var(--color-accent);
  font-weight: 500;
}

.hero-badges {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.badge {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  padding: 4px 14px;
  border-radius: 999px;
  font-size: .82rem;
  font-weight: 500;
  box-shadow: 0 1px 4px rgba(0,0,0,.06);
}

.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-size: .95rem;
  font-weight: 600;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
}

.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background: var(--color-accent);
  color: #fff;
  box-shadow: 0 4px 14px rgba(37,99,235,.35);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  color: #fff;
  box-shadow: 0 6px 20px rgba(37,99,235,.45);
}

.btn-outline {
  background: var(--color-surface);
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
  box-shadow: var(--shadow);
}

.btn-outline:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.hero-scroll-hint {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--color-text-muted);
  font-size: .75rem;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.scroll-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--color-text-muted), transparent);
  animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
  0%, 100% { opacity: .4; transform: scaleY(1); }
  50% { opacity: 1; transform: scaleY(.6); }
}

/* =============================================
   共通セクションスタイル
   ============================================= */
.section {
  padding: 96px 24px;
}

.section-alt {
  background: var(--color-bg-alt);
}

.container {
  max-width: 1100px;
  margin: 0 auto;
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -.03em;
  color: var(--color-text);
  margin-bottom: 56px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -10px;
  width: 40px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
}

/* タグ */
.tag {
  display: inline-block;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  padding: 3px 12px;
  border-radius: 999px;
  font-size: .8rem;
  font-weight: 500;
}

/* =============================================
   About セクション
   ============================================= */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}

.about-text p {
  color: var(--color-text-muted);
  margin-bottom: 18px;
  font-size: .97rem;
  line-height: 1.85;
}

.about-text p strong {
  color: var(--color-text);
  font-weight: 600;
}

.about-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.stat-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px 20px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.stat-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

.stat-number {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1;
  margin-bottom: 6px;
}

.stat-label {
  font-size: .8rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

/* =============================================
   Skills セクション
   ============================================= */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.skill-category {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.skill-category:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}

.skill-cat-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.skill-icon { font-size: 1.1rem; }

.skill-list { list-style: none; display: flex; flex-direction: column; gap: 12px; }

.skill-item {
  display: flex;
  align-items: center;
  gap: 12px;
}

.skill-name {
  min-width: 120px;
  font-size: .87rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.skill-bar {
  flex: 1;
  height: 6px;
  background: var(--color-border);
  border-radius: 999px;
  overflow: hidden;
}

.skill-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-accent), #60a5fa);
  border-radius: 999px;
  width: 0;
  transition: width 1s cubic-bezier(.4,0,.2,1);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

/* =============================================
   Experience セクション
   ============================================= */
.timeline {
  position: relative;
  padding-left: 32px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 10px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--color-accent), var(--color-border));
  border-radius: 2px;
}

.timeline-item {
  position: relative;
  margin-bottom: 48px;
}

.timeline-item:last-child { margin-bottom: 0; }

.timeline-marker {
  position: absolute;
  left: -27px;
  top: 6px;
  width: 14px;
  height: 14px;
  background: var(--color-accent);
  border: 3px solid var(--color-bg);
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--color-accent);
}

.timeline-content {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px 32px;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.timeline-content:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-hover);
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.timeline-company {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
}

.timeline-role {
  font-size: .9rem;
  color: var(--color-accent);
  font-weight: 500;
  margin-top: 4px;
}

.timeline-period {
  font-size: .82rem;
  color: var(--color-text-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: 4px 12px;
  border-radius: 999px;
  white-space: nowrap;
  font-weight: 500;
}

.timeline-desc {
  list-style: none;
  margin-bottom: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.timeline-desc li {
  font-size: .9rem;
  color: var(--color-text-muted);
  padding-left: 16px;
  position: relative;
  line-height: 1.7;
}

.timeline-desc li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-size: .75rem;
  top: .25em;
}

.timeline-desc li strong {
  color: var(--color-text);
  font-weight: 600;
}

.timeline-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

/* =============================================
   BI & Decision Architecture セクション
   ============================================= */
.bi-lead {
  font-size: 1rem;
  color: var(--color-text-muted);
  line-height: 1.85;
  max-width: 760px;
  margin: 0 auto 48px;
  text-align: center;
}

.bi-lead strong {
  color: var(--color-text);
  font-weight: 600;
}

.bi-method-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-bottom: 56px;
}

.bi-method-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.bi-method-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

.bi-method-icon {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.bi-method-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 12px;
  line-height: 1.4;
}

.bi-method-desc {
  font-size: .85rem;
  color: var(--color-text-muted);
  line-height: 1.75;
}

.bi-method-desc strong {
  color: var(--color-text);
  font-weight: 600;
}

.bi-section-subtitle {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 20px;
  padding-left: 12px;
  border-left: 4px solid var(--color-accent);
  line-height: 1.4;
}

.bi-cases-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.bi-case-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: transform var(--transition), box-shadow var(--transition);
}

.bi-case-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.bi-case-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.bi-case-tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--color-accent);
  color: #fff;
  font-size: .72rem;
  font-weight: 600;
  border-radius: 999px;
  letter-spacing: .03em;
}

.bi-case-period {
  font-size: .78rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.bi-case-title {
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.45;
}

.bi-case-desc {
  font-size: .87rem;
  color: var(--color-text-muted);
  line-height: 1.75;
}

.bi-case-desc strong {
  color: var(--color-text);
  font-weight: 600;
}

.bi-case-points {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: .82rem;
  color: var(--color-text-muted);
}

.bi-case-points li {
  position: relative;
  padding-left: 16px;
  line-height: 1.6;
}

.bi-case-points li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 9px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
}

.bi-case-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  padding: 14px 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.bi-case-stat {
  text-align: center;
}

.bi-case-stat-num {
  display: block;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1.2;
}

.bi-case-stat-label {
  display: block;
  font-size: .72rem;
  color: var(--color-text-muted);
  margin-top: 2px;
}

.bi-case-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 4px;
}

/* =============================================
   Projects セクション
   ============================================= */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.project-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: transform var(--transition), box-shadow var(--transition);
}

.project-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.project-icon { font-size: 1.8rem; }

.project-links a {
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.project-links a:hover { color: var(--color-accent); }

.project-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.4;
}

.project-desc {
  font-size: .87rem;
  color: var(--color-text-muted);
  line-height: 1.75;
  flex: 1;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 4px;
}

/* =============================================
   Contact セクション
   ============================================= */
.contact-container {
  text-align: center;
}

.contact-desc {
  color: var(--color-text-muted);
  font-size: 1rem;
  max-width: 500px;
  margin: 0 auto 40px;
  line-height: 1.75;
}

.contact-links {
  display: flex;
  gap: 20px;
  justify-content: center;
  flex-wrap: wrap;
}

.contact-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 32px 48px;
  color: var(--color-text-muted);
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition), color var(--transition), border-color var(--transition);
  font-weight: 500;
  font-size: .95rem;
}

.contact-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* =============================================
   フッター
   ============================================= */
footer {
  background: var(--color-text);
  color: rgba(255,255,255,.45);
  text-align: center;
  padding: 28px 24px;
  font-size: .82rem;
}

/* =============================================
   アニメーション
   ============================================= */
.fade-up {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp .7s ease forwards;
}

.delay-1 { animation-delay: .15s; }
.delay-2 { animation-delay: .3s; }
.delay-3 { animation-delay: .45s; }
.delay-4 { animation-delay: .6s; }

@keyframes fadeUp {
  to { opacity: 1; transform: translateY(0); }
}

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .6s ease, transform .6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal.delay-1 { transition-delay: .1s; }
.reveal.delay-2 { transition-delay: .2s; }
.reveal.delay-3 { transition-delay: .3s; }

/* =============================================
   レスポンシブ
   ============================================= */
@media (max-width: 900px) {
  .about-grid {
    grid-template-columns: 1fr;
  }

  .skills-grid {
    grid-template-columns: 1fr;
  }

  .projects-grid {
    grid-template-columns: 1fr 1fr;
  }

  .bi-method-grid {
    grid-template-columns: 1fr;
  }

  .bi-cases-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  .nav-links { display: none; }
  .hamburger { display: flex; }

  .section { padding: 72px 20px; }

  #hero {
    padding: calc(var(--nav-height) + 40px) 20px 60px;
  }

  .about-stats {
    grid-template-columns: 1fr 1fr;
  }

  .projects-grid {
    grid-template-columns: 1fr;
  }

  .bi-cases-grid {
    grid-template-columns: 1fr;
  }

  .timeline { padding-left: 24px; }
  .timeline-marker { left: -21px; }

  .timeline-content { padding: 20px; }

  .timeline-header {
    flex-direction: column;
    gap: 8px;
  }

  .contact-card { padding: 24px 36px; }
}