/* ---------- Introduction: editable keyword network ---------- */

.introduction-scroll {
  width: 100%;
  height: 100%;
  overflow-y: auto;
  padding: 40px clamp(20px, 5vw, 64px) 64px;
}

.introduction-content {
  max-width: 980px;
  margin: 0 auto;
}

.intro-heading {
  margin: 0 0 20px;
  font-size: clamp(18px, 2.4vw, 24px);
  font-weight: 400;
  letter-spacing: -0.01em;
  text-align: center;
  color: var(--ink);
}

/* ---------- Toolbar ---------- */

.intro-toolbar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 36px;
}

.intro-toolbar-btn {
  font-family: inherit;
  font-size: 11px;
  letter-spacing: 0.03em;
  color: var(--ink-soft);
  background: none;
  border: 1px solid var(--hairline);
  border-radius: 20px;
  padding: 6px 14px;
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.intro-toolbar-btn:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.intro-toolbar-hint {
  font-size: 11px;
  color: var(--ink-soft);
  opacity: 0;
  transition: opacity 0.25s ease;
}

.intro-toolbar-hint.is-visible {
  opacity: 1;
}

/* ---------- Layer 1: keyword chain ---------- */

.intro-chain {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  row-gap: 20px;
  margin-bottom: 8px;
}

.intro-connector {
  width: 28px;
  height: 1px;
  min-width: 16px;
  flex: 0 1 28px;
  background: var(--hairline);
}

.intro-node {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 96px;
  height: 96px;
  padding: 8px 14px;
  border-radius: 50%;
  background: var(--tone-matrix);
  border: 1px solid rgba(17, 17, 17, 0.08);
  text-align: center;
}

.intro-node-text {
  font-size: 12.5px;
  font-weight: 400;
  letter-spacing: 0.01em;
  line-height: 1.3;
  color: var(--ink);
  outline: none;
  max-width: 88px;
}

.intro-node-remove {
  position: absolute;
  top: 2px;
  right: 2px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 1px solid var(--hairline);
  background: #ffffff;
  color: var(--ink-soft);
  font-size: 11px;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.intro-node:hover .intro-node-remove {
  opacity: 1;
}

.intro-node-remove:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.intro-node-add {
  font-family: inherit;
  font-size: 20px;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
  background: none;
  border: 1px dashed var(--hairline);
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.intro-node-add:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.intro-add-input {
  width: 140px;
  height: 40px;
  padding: 0 12px;
  font-family: inherit;
  font-size: 12.5px;
  color: var(--ink);
  background: #ffffff;
  border: 1px solid var(--ink);
  border-radius: 20px;
  outline: none;
}

/* ---------- Flow arrow between layers ---------- */

.intro-flow-arrow {
  text-align: center;
  font-size: 20px;
  color: var(--ink-soft);
  margin: 12px 0 32px;
}

/* ---------- Layer 2: numbered filter timeline ---------- */

.intro-filters {
  position: relative;
  padding-left: 56px;
}

.intro-filters::before {
  content: '';
  position: absolute;
  left: 19px;
  top: 20px;
  bottom: 20px;
  width: 1px;
  background: var(--hairline);
}

.intro-filter {
  position: relative;
  display: flex;
  gap: 20px;
  padding-bottom: 40px;
}

.intro-filter:last-child {
  padding-bottom: 0;
}

.intro-filter-num {
  position: absolute;
  left: -56px;
  top: 0;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: #ffffff;
  border: 1px solid var(--ink);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.03em;
  color: var(--ink);
  flex: 0 0 auto;
}

.intro-filter-body {
  flex: 1 1 auto;
  min-width: 0;
}

.intro-filter-title {
  margin: 6px 0 6px;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: -0.005em;
  color: var(--ink);
}

.intro-filter-question {
  margin: 0 0 16px;
  font-size: 13.5px;
  font-style: italic;
  color: var(--ink-soft);
}

.intro-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.intro-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 8px 6px 12px;
  border-radius: 16px;
  background: var(--tone-mex);
  border: 1px solid rgba(17, 17, 17, 0.08);
}

.intro-chip-text {
  font-size: 12px;
  color: var(--ink);
  outline: none;
  white-space: nowrap;
}

.intro-chip-remove {
  width: 15px;
  height: 15px;
  border-radius: 50%;
  border: none;
  background: rgba(17, 17, 17, 0.08);
  color: var(--ink-soft);
  font-size: 10px;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s ease, color 0.15s ease;
}

.intro-chip-remove:hover {
  background: var(--ink);
  color: #ffffff;
}

.intro-chip-add {
  font-family: inherit;
  font-size: 14px;
  color: var(--ink-soft);
  background: none;
  border: 1px dashed var(--hairline);
  border-radius: 16px;
  padding: 6px 12px;
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.intro-chip-add:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.intro-add-input-chip {
  width: 130px;
  height: 28px;
  border-radius: 14px;
}

.intro-filter-note {
  margin: 0;
  max-width: 560px;
  font-size: 13px;
  font-style: italic;
  line-height: 1.65;
  color: var(--ink-soft);
}

@media (max-width: 640px) {
  .intro-node { min-width: 88px; height: 88px; }
  .intro-node-text { font-size: 10.5px; max-width: 80px; }
  .intro-filters { padding-left: 44px; }
  .intro-filters::before { left: 15px; }
  .intro-filter-num { left: -44px; width: 32px; height: 32px; font-size: 11px; }
}