/* =========================================
   Base & Reset (Premium Executive Dark)
========================================= */
:root {
  --color-bg: #0f1115;
  --color-bg-card: #181b21;
  --color-bg-glass: rgba(255, 255, 255, 0.02);
  --color-text: #d1d5db;
  --color-heading: #f9fafb;
  --color-accent: #d4af37; /* Premium Gold */
  --color-accent-light: #f5df9a;
  --color-border: rgba(255, 255, 255, 0.08);
  --color-timeline: rgba(212, 175, 55, 0.3);
  
  --font-main: 'Noto Sans JP', sans-serif;
  --font-heading: 'Noto Serif JP', serif;
  
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 10px 25px -5px rgba(0, 0, 0, 0.8);
  --shadow-glow: 0 0 20px rgba(212, 175, 55, 0.15);
}

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

body {
  font-family: var(--font-main);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.8;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px;
}

/* =========================================
   Typography
========================================= */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--color-heading);
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: 0.05em;
  margin-bottom: 1.5rem;
}

h1 { font-size: 2.5rem; text-align: center; margin-top: 0; }
h2 { 
  font-size: 1.8rem; 
  margin-top: 4rem; 
  border-bottom: 1px solid var(--color-border); 
  padding-bottom: 1rem; 
}
h3 { font-size: 1.4rem; margin-top: 3rem; color: var(--color-accent-light); }

p { margin-bottom: 1.5rem; }

.accent {
  color: var(--color-accent) !important;
  font-weight: 700;
}

strong { font-weight: 700; color: #fff; }

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: all 0.3s ease;
}
a:hover {
  color: var(--color-accent-light);
  text-shadow: 0 0 8px rgba(212, 175, 55, 0.4);
}

/* =========================================
   Layout & Header/Footer
========================================= */
.site-header {
  padding: 1rem 0;
  text-align: center;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 1rem;
}
.site-header .logo-placeholder {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--color-accent);
  font-size: 1.6rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.site-footer {
  text-align: center;
  padding: 2rem 0 4rem 0;
  color: #6b7280;
  font-size: 0.9rem;
  margin-top: 2rem;
  border-top: 1px solid var(--color-border);
}

/* =========================================
   Components
========================================= */
/* Hero Section */
.hero {
  text-align: center;
  margin-bottom: 1rem;
  padding: 1rem 0;
}
.hero h1 {
  background: linear-gradient(135deg, #f5df9a, #d4af37);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 1.5rem;
  font-size: 3rem;
}
.hero p {
  font-size: 1.2rem;
  color: #9ca3af;
  max-width: 600px;
  margin: 0 auto;
  line-height: 2;
}

/* Timeline (Learning Map) */
.timeline {
  position: relative;
  margin: 2rem 0 2rem 0;
  padding: 1rem 0;
}
.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  background: linear-gradient(to bottom, transparent, var(--color-accent), transparent);
  transform: translateX(-50%);
}

.timeline-item {
  position: relative;
  margin-bottom: 4rem;
  width: 50%;
  padding-right: 4rem;
  left: 0;
}
.timeline-item:last-child {
  margin-bottom: 0;
}
.timeline-item:nth-child(even) {
  left: 50%;
  padding-right: 0;
  padding-left: 4rem;
}

.timeline-badge {
  position: absolute;
  top: 0;
  right: -25px;
  width: 50px;
  height: 50px;
  background-color: var(--color-bg);
  color: var(--color-accent);
  border: 2px solid var(--color-accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-weight: 700;
  z-index: 10;
  box-shadow: var(--shadow-glow);
  transition: all 0.4s ease;
}
.timeline-item:nth-child(even) .timeline-badge {
  left: -25px;
  right: auto;
}

.timeline-content {
  background: var(--color-bg-card);
  padding: 2.5rem;
  border-radius: 16px;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  display: block;
  text-decoration: none;
  position: relative;
  overflow: hidden;
}
.timeline-content::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
  background: var(--color-accent);
  opacity: 0;
  transition: opacity 0.3s ease;
}
.timeline-item:hover .timeline-content {
  transform: translateY(-5px);
  border-color: rgba(212, 175, 55, 0.3);
  box-shadow: var(--shadow-glow);
}
.timeline-item:hover .timeline-content::before {
  opacity: 1;
}
.timeline-item:hover .timeline-badge {
  background-color: var(--color-accent);
  color: var(--color-bg);
  transform: scale(1.1);
}
.timeline-content h3 {
  margin-top: 0;
  margin-bottom: 1rem;
  font-size: 1.4rem;
  color: var(--color-heading);
}
.timeline-content p {
  margin-bottom: 0;
  color: #9ca3af;
}

/* Responsive Timeline */
@media (max-width: 768px) {
  .timeline::before {
    left: 25px;
  }
  .timeline-item {
    width: 100%;
    left: 0 !important;
    padding-left: 70px !important;
    padding-right: 0 !important;
  }
  .timeline-badge {
    left: 0 !important;
    right: auto !important;
  }
}

/* Page Header */
.page-header {
  text-align: center;
  margin-bottom: 2rem;
}
.page-header h1 {
  font-size: 2.4rem;
  margin-bottom: 0.5rem;
}
.page-intro {
  font-size: 1.2rem;
  color: #9ca3af;
  max-width: 700px;
  margin: 0 auto 2rem;
  text-align: left;
}

/* Summary Box (この章で学ぶこと) */
.summary-box {
  background: linear-gradient(145deg, var(--color-bg-card), #14161b);
  border: 1px solid var(--color-border);
  padding: 2rem;
  border-radius: 16px;
  margin-bottom: 3rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  box-shadow: var(--shadow-md);
}
.summary-content h3 {
  margin-top: 0;
  margin-bottom: 2rem;
  text-align: center;
  font-size: 1.6rem;
  color: var(--color-accent);
}
.summary-content ul {
  list-style-type: none;
  padding: 0;
  display: inline-block;
  text-align: left;
}
.summary-content li {
  position: relative;
  padding-left: 2rem;
  margin-bottom: 1rem;
  font-size: 1.1rem;
  color: var(--color-heading);
}
.summary-content li::before {
  content: '✨';
  position: absolute;
  left: 0;
  font-size: 1.2rem;
}

/* Story Card (筆者のリアル) */
.story-card {
  background: var(--color-bg-glass);
  border-left: 4px solid var(--color-accent);
  padding: 2.5rem;
  margin: 1.5rem 0 3.5rem 0;
  border-radius: 0 12px 12px 0;
  backdrop-filter: blur(10px);
}
.story-label {
  display: inline-flex;
  align-items: center;
  gap: 0.8rem;
  font-family: var(--font-heading);
  color: var(--color-accent);
  margin-bottom: 1.5rem;
  font-size: 1.2rem;
  letter-spacing: 0.1em;
}
.story-card p {
  line-height: 2;
  margin-bottom: 1.5rem;
  color: #cbd5e1;
}
.story-card p:last-child {
  margin-bottom: 0;
}

/* Action Card (WORK) */
.action-card {
  background: #111318;
  border-top: 4px solid var(--color-accent);
  padding: 2rem 3rem 3.5rem 3rem;
  margin: 1.5rem 0 5rem 0;
  border-radius: 0 0 16px 16px;
  box-shadow: var(--shadow-md);
  border-bottom: 1px solid var(--color-border);
  border-left: 1px solid var(--color-border);
  border-right: 1px solid var(--color-border);
}
.action-label {
  display: block;
  text-align: center;
  font-family: var(--font-heading);
  color: var(--color-heading);
  font-size: 1.6rem;
  margin-bottom: 2.5rem;
  letter-spacing: 0.1em;
}
.work-grid {
  display: grid;
  gap: 2rem;
  grid-template-columns: repeat(3, 1fr);
}
@media (max-width: 768px) {
  .work-grid {
    grid-template-columns: 1fr;
  }
}
.work-item {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  padding: 2rem;
  border-radius: 12px;
  transition: transform 0.3s ease, border-color 0.3s ease;
}
.work-item:hover {
  transform: translateY(-3px);
  border-color: rgba(212, 175, 55, 0.4);
}
.work-item h4 {
  margin-top: 0;
  color: var(--color-accent);
  font-size: 1.2rem;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 1rem;
  margin-bottom: 1.5rem;
}
.work-item p {
  font-size: 0.95rem;
  margin-bottom: 0;
  color: #9ca3af;
}

/* 2 Column Card (比較用) */
.comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
  margin: 4rem 0;
}
.comparison-card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  padding: 2.5rem;
  border-radius: 16px;
  box-shadow: var(--shadow-md);
}
.comparison-card h4 {
  margin-top: 0;
  margin-bottom: 2rem;
  text-align: center;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
}
.comparison-card.left-card h4 {
  color: #9ca3af;
}
.comparison-card.right-card h4 {
  color: var(--color-accent);
}
.comparison-card ul {
  padding-left: 1.5rem;
}
.comparison-card li {
  margin-bottom: 1rem;
  color: #cbd5e1;
}
@media (max-width: 768px) {
  .comparison-grid {
    grid-template-columns: 1fr;
  }
}

/* Quote Block (引用) */
.quote-block {
  border-left: 4px solid var(--color-accent);
  background: linear-gradient(90deg, rgba(212,175,55,0.05), transparent);
  padding: 2rem 2.5rem;
  margin: 3.5rem 0;
  font-family: var(--font-heading);
  font-size: 1.3rem;
  color: var(--color-accent-light);
  font-style: italic;
  border-radius: 0 12px 12px 0;
}
.quote-block p {
  margin-bottom: 0;
  line-height: 1.8;
}

/* Note Box (注意書き) */
.note-box {
  background-color: rgba(255, 255, 255, 0.02);
  border: 1px dashed var(--color-border);
  padding: 2rem;
  border-radius: 12px;
  margin: 3rem 0;
  font-size: 0.95rem;
  color: #9ca3af;
}

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 3rem 0;
  background-color: var(--color-bg-card);
  box-shadow: var(--shadow-md);
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid var(--color-border);
}
th, td {
  padding: 1.5rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}
th {
  background-color: #111318;
  color: var(--color-accent);
  font-family: var(--font-heading);
  font-weight: 700;
  letter-spacing: 0.05em;
}
tr:last-child td {
  border-bottom: none;
}
@media (max-width: 768px) {
  table, thead, tbody, th, td, tr {
    display: block;
  }
  th {
    display: none;
  }
  tr {
    margin-bottom: 1.5rem;
    border: 1px solid var(--color-border);
    border-radius: 12px;
  }
  td {
    text-align: right;
    padding-left: 50%;
    position: relative;
    border-bottom: 1px dotted var(--color-border);
  }
  td::before {
    content: attr(data-label);
    position: absolute;
    left: 1.5rem;
    width: 45%;
    text-align: left;
    font-weight: bold;
    color: var(--color-accent);
  }
}

/* Page Navigation */
.page-nav {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}
.btn-primary {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  min-width: 340px;
  min-height: 85px;
  background: linear-gradient(135deg, var(--color-accent), #b8860b);
  color: #000;
  padding: 1.2rem 2.5rem;
  border-radius: 40px;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.2rem;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(212, 175, 55, 0.2);
}
.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(212, 175, 55, 0.4);
  color: #000;
}
.nav-prev {
  font-size: 1rem;
  color: #6b7280;
}
.nav-prev:hover {
  color: var(--color-heading);
}

/* Table of Contents */
.toc-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  background: var(--color-bg-card);
  padding: 3.5rem;
  border-radius: 16px;
  box-shadow: var(--shadow-md);
  margin-bottom: 5rem;
  border: 1px solid var(--color-border);
}
.toc-wrapper .toc {
  flex: 1 1 auto;
  white-space: nowrap;
  text-align: left;
}
.toc-wrapper .toc-img {
  flex: 0 0 350px;
  width: 100%;
  max-width: 350px;
  height: auto;
  aspect-ratio: 16/9;
  object-fit: cover;
  border-radius: 12px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.5);
  border: 1px solid var(--color-border);
  margin-left: auto;
}
@media (max-width: 768px) {
  .toc-wrapper {
    flex-direction: column;
    align-items: flex-start;
  }
  .toc-wrapper .toc {
    white-space: normal;
  }
  .toc-wrapper .toc-img {
    max-width: 100%;
    margin-left: 0;
  }
}
.toc ol {
  margin-left: 1.5rem;
  margin-bottom: 0;
  font-size: 1.1rem;
  font-feature-settings: "palt" 1;
}
.toc li {
  margin-bottom: 0.8rem;
  color: #cbd5e1;
}