:root {
  color-scheme: light;
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-subtle: #f8fafc;
  --border: #d7deea;
  --border-strong: #b8c4d7;
  --text: #1f2937;
  --muted: #5b6678;
  --accent: #2f6fec;
  --accent-hover: #245ed0;
  --accent-soft: #eef4ff;
  --shadow: 0 12px 36px rgba(16, 24, 40, 0.08);
  --radius: 16px;
  --layer-1-bg: #f1f8ff;
  --layer-1-border: #b8d8f2;
  --layer-2-bg: #f3fbf4;
  --layer-2-border: #b9dfc0;
  --layer-3-bg: #fff8e8;
  --layer-3-border: #e7c97c;
  --layer-4-bg: #ffffe1;
  --layer-4-border: #ebea69;
  --layer-5-bg: #f3eeff;
  --layer-5-border: #b89be8;
  --layer-6-bg: #ffffff;
  --layer-6-border: #d6d6d6;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
}

button,
input,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

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

.page-shell {
  min-height: 100vh;
}

.page-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(245, 247, 251, 0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(183, 195, 214, 0.7);
}

.page-header-inner,
.page-main {
  width: min(100%, 56rem);
  margin: 0 auto;
  padding-left: 1rem;
  padding-right: 1rem;
}

.page-header-inner {
  padding-top: max(1rem, env(safe-area-inset-top));
  padding-bottom: 0.9rem;
}

.page-main {
  padding-top: 1rem;
  padding-bottom: calc(2rem + env(safe-area-inset-bottom));
}

.page-eyebrow {
  margin: 0 0 0.25rem;
  color: var(--muted);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.page-title {
  margin: 0;
  font-size: 1.4rem;
  line-height: 1.3;
}

.page-intro {
  margin: 0.55rem 0 0;
  color: var(--muted);
  font-size: 0.94rem;
  line-height: 1.65;
}

.search-form {
  margin-top: 0.9rem;
}

.search-label {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.92rem;
  font-weight: 700;
}

.search-row {
  display: flex;
  gap: 0.55rem;
}

.search-input {
  flex: 1 1 auto;
  width: 100%;
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  background: var(--surface);
  padding: 0.8rem 0.9rem;
  color: var(--text);
}

.search-input:focus,
.free-text-input:focus,
.branch-toggle:focus,
.ai-help-button:focus,
.search-clear:focus,
.primary-button:focus,
.modal-close:focus {
  outline: 2px solid rgba(47, 111, 236, 0.3);
  outline-offset: 2px;
}

.search-clear,
.primary-button,
.ai-help-button {
  border: 1px solid transparent;
  border-radius: 12px;
  padding: 0.78rem 0.95rem;
  font-weight: 700;
}

.search-clear {
  flex: 0 0 auto;
  background: var(--surface);
  border-color: var(--border-strong);
  color: var(--text);
}

.search-status {
  margin: 0.45rem 0 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.message-card,
.leaf-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.message-card {
  padding: 1rem;
}

.message-card-error {
  border-color: #efb3b3;
  background: #fff4f4;
}

.message-title {
  margin: 0;
  font-weight: 700;
}

.message-body {
  margin: 0.4rem 0 0;
  color: var(--muted);
}

.help-tree {
  display: grid;
  gap: 0.85rem;
}

.tree-group {
  display: grid;
  gap: 0.8rem;
}

.branch-block {
  display: grid;
  gap: 0.55rem;
}

.branch-toggle {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.8rem;
  padding: 0.95rem 1rem;
  border: 1px solid var(--item-border, var(--border-strong));
  border-radius: 14px;
  background: var(--item-bg, var(--surface));
  color: var(--text);
  text-align: left;
  box-shadow: var(--shadow);
  transition: background-color 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}

.branch-toggle:hover {
  transform: translateY(-1px);
}

.branch-toggle.is-open {
  box-shadow: 0 14px 30px rgba(16, 24, 40, 0.1);
}

.branch-label {
  min-width: 0;
  display: grid;
  gap: 0.18rem;
  line-height: 1.45;
}

.branch-label-primary {
  font-weight: 700;
}

.branch-label-meta {
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 500;
}

.branch-icon {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 1rem;
}

.branch-children {
  padding: 0 0 0 0.85rem;
  display: grid;
  gap: 0.75rem;
  border-left: 2px solid rgba(184, 196, 215, 0.7);
}

.leaf-card {
  padding: 0.95rem;
  background: var(--item-bg, var(--surface-subtle));
  border-color: var(--item-border, var(--border));
}

.leaf-title {
  margin: 0 0 0.45rem;
  font-size: 0.96rem;
  font-weight: 700;
  line-height: 1.45;
}

.leaf-meta {
  margin: -0.1rem 0 0.45rem;
  color: var(--muted);
  font-size: 0.85rem;
  line-height: 1.5;
}

.layer-surface-1 {
  --item-bg: var(--layer-1-bg);
  --item-border: var(--layer-1-border);
}

.layer-surface-2 {
  --item-bg: var(--layer-2-bg);
  --item-border: var(--layer-2-border);
}

.layer-surface-3 {
  --item-bg: var(--layer-3-bg);
  --item-border: var(--layer-3-border);
}

.layer-surface-4 {
  --item-bg: var(--layer-4-bg);
  --item-border: var(--layer-4-border);
}

.layer-surface-5 {
  --item-bg: var(--layer-5-bg);
  --item-border: var(--layer-5-border);
}

.layer-surface-6 {
  --item-bg: var(--layer-6-bg);
  --item-border: var(--layer-6-border);
}

.leaf-body {
  margin: 0;
  color: inherit;
  word-break: break-word;
}

.leaf-body br {
  content: "";
}

.ai-help-wrap {
  margin-top: 0.7rem;
}

.ai-help-button {
  width: 100%;
  background: var(--accent-soft);
  border-color: #bfd0fb;
  color: #17439c;
}

.ai-help-button:hover {
  background: #e4eeff;
}

mark {
  background: #fff0a6;
  color: inherit;
  padding: 0 0.08em;
  border-radius: 0.15em;
}

.empty-search {
  padding: 1rem;
  border: 1px dashed var(--border-strong);
  border-radius: 14px;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.65);
  text-align: center;
}

.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding: 1rem;
  background: rgba(15, 23, 42, 0.42);
}

.modal-overlay[hidden] {
  display: none;
}

.modal-card {
  width: min(100%, 34rem);
  max-height: calc(100vh - 2rem);
  overflow: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: 0 20px 48px rgba(15, 23, 42, 0.18);
}

.modal-header,
.modal-body,
.modal-actions {
  padding-left: 1rem;
  padding-right: 1rem;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  align-items: center;
  padding-top: 1rem;
}

.modal-title {
  margin: 0;
  font-size: 1.1rem;
}

.modal-close {
  width: 2.2rem;
  height: 2.2rem;
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  background: var(--surface);
}

.modal-body {
  padding-top: 0.7rem;
  padding-bottom: 0.85rem;
}

.modal-lead {
  margin: 0 0 0.8rem;
  font-weight: 700;
}

.choice-list {
  display: grid;
  gap: 0.65rem;
}

.choice-item {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
  padding: 0.85rem;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface-subtle);
}

.choice-item input {
  margin-top: 0.15rem;
}

.free-text-block {
  display: block;
  margin-top: 0.95rem;
}

.free-text-label {
  display: block;
  margin-bottom: 0.4rem;
  font-weight: 700;
}

.free-text-input {
  width: 100%;
  resize: vertical;
  min-height: 6rem;
  border: 1px solid var(--border-strong);
  border-radius: 14px;
  background: var(--surface);
  padding: 0.85rem 0.9rem;
  color: var(--text);
}

.modal-actions {
  padding-top: 0;
  padding-bottom: calc(1rem + env(safe-area-inset-bottom));
}

.primary-button {
  width: 100%;
  background: var(--accent);
  color: #fff;
}

.primary-button:hover {
  background: var(--accent-hover);
}

@media (min-width: 720px) {
  .page-header-inner,
  .page-main {
    padding-left: 1.25rem;
    padding-right: 1.25rem;
  }

  .modal-overlay {
    align-items: center;
  }

  .branch-children {
    padding: 1rem;
  }
}