:root {
  --paper: #f7f6f2;
  --ink: #111110;
  --ink-70: rgba(17, 17, 16, 0.74);
  --ink-42: rgba(17, 17, 16, 0.6);
  --ink-15: rgba(17, 17, 16, 0.16);
  --ink-06: rgba(17, 17, 16, 0.06);
  --accent: #003b8e;
  --accent-15: rgba(0, 59, 142, 0.12);
  --font-sans: "IBM Plex Sans JP", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background-color: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-weight: 400;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.page {
  max-width: 1320px;
  margin: 0 auto;
  padding: 32px 40px 64px;
}

/* Topbar */
.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--ink-15);
  gap: 24px;
  flex-wrap: wrap;
}

.topbar-brand {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--ink-70);
}

.topbar-nav {
  display: flex;
  gap: 24px;
}

.nav-tab {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 6px 0;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: var(--ink-42);
  cursor: pointer;
  transition: color 150ms cubic-bezier(0.22, 1, 0.36, 1),
    border-color 150ms cubic-bezier(0.22, 1, 0.36, 1);
}

.nav-tab:hover {
  color: var(--ink);
}

.nav-tab.is-active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* Hero */
.hero {
  padding: 48px 0 40px;
  border-bottom: 1px solid var(--ink-15);
}

.hero-title {
  margin: 0 0 16px;
  font-size: clamp(1.85rem, 3.6vw, 3.1rem);
  font-weight: 300;
  line-height: 1.18;
  letter-spacing: -0.03em;
  text-wrap: balance;
}

.hero-lead {
  margin: 0;
  max-width: 60ch;
  font-size: 0.95rem;
  color: var(--ink-70);
}

/* 12-Column Asymmetric Grid */
.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 48px;
  padding-top: 40px;
}

.col-4 {
  grid-column: span 4;
}

.col-8 {
  grid-column: span 8;
}

/* Controls Pane */
.section-block {
  padding-bottom: 32px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--ink-15);
}

.section-block:last-child {
  border-bottom: none;
  margin-bottom: 0;
}

.section-label {
  margin: 0 0 16px;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-42);
}

.preset-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.preset-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  width: 100%;
  padding: 12px 12px 12px 0;
  background: none;
  border: none;
  border-top: 1px solid var(--ink-15);
  border-left: 2px solid transparent;
  text-align: left;
  cursor: pointer;
  transition: border-color 140ms ease, padding-left 140ms ease;
}

.preset-btn:last-child {
  border-bottom: 1px solid var(--ink-15);
}

.preset-btn:hover {
  padding-left: 8px;
}

.preset-btn.is-active {
  padding-left: 10px;
  border-left-color: var(--accent);
}

.preset-name {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink);
}

.preset-btn.is-active .preset-name {
  color: var(--accent);
}

.preset-desc {
  font-size: 0.78rem;
  color: var(--ink-70);
}

/* Sliders */
.sliders {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.slider-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 6px;
  font-size: 0.84rem;
}

.slider-head label {
  color: var(--ink-70);
}

.slider-val {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.84rem;
  color: var(--ink);
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 2px;
  background: var(--ink-15);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  transition: transform 120ms ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.25);
}

/* KPI Strip */
.kpi-strip {
  display: grid;
  grid-template-columns: 2fr repeat(4, 1fr);
  gap: 20px;
  padding-bottom: 24px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--ink-15);
}

.kpi-label {
  font-size: 0.74rem;
  color: var(--ink-42);
  margin-bottom: 4px;
}

.kpi-phase {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--accent);
  line-height: 1.35;
}

.kpi-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.65rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  color: var(--ink);
}

/* View Panels */
.view-panel {
  display: none;
}

.view-panel.is-active {
  display: block;
}

.panel-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 20px;
  gap: 16px;
  flex-wrap: wrap;
}

.panel-title {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 400;
  letter-spacing: -0.01em;
}

.legend {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 0.76rem;
  color: var(--ink-70);
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.line-swatch {
  display: inline-block;
  width: 18px;
  height: 0;
  border-top: 2px solid var(--ink);
}

.swatch-accent {
  border-top-color: var(--accent);
  border-top-width: 2.5px;
}

.swatch-solid {
  border-top-color: var(--ink);
}

.swatch-dashed {
  border-top-style: dashed;
  border-top-color: var(--ink-70);
}

.swatch-dotted {
  border-top-style: dotted;
  border-top-color: var(--ink-42);
}

.chart-wrap,
.network-wrap {
  width: 100%;
  border-top: 1px solid var(--ink-15);
  border-bottom: 1px solid var(--ink-15);
  padding: 16px 0;
}

.chart-wrap svg,
.network-wrap svg {
  display: block;
  width: 100%;
  height: auto;
}

.network-meta {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.78rem;
  color: var(--ink-70);
}

.sim-note {
  margin: 18px 0 0;
  max-width: 60ch;
  font-size: 0.86rem;
  color: var(--ink-70);
}

/* Theory View */
.theory-list {
  border-top: 1px solid var(--ink-15);
}

.theory-row {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 20px;
  padding: 24px 0;
  border-bottom: 1px solid var(--ink-15);
}

.theory-idx {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent);
}

.theory-body h4 {
  margin: 0 0 8px;
  font-size: 1rem;
  font-weight: 500;
}

.theory-body p {
  margin: 0;
  max-width: 60ch;
  font-size: 0.88rem;
  color: var(--ink-70);
}

/* Footer */
.footer {
  margin-top: 64px;
  padding-top: 20px;
  border-top: 1px solid var(--ink-15);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 0.75rem;
  color: var(--ink-42);
}

@media (max-width: 960px) {
  .page {
    padding: 24px 20px 48px;
  }

  .grid-12 {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .col-4,
  .col-8 {
    grid-column: span 1;
  }

  .kpi-strip {
    grid-template-columns: repeat(2, 1fr);
  }

  .kpi-item:first-child {
    grid-column: span 2;
  }
}