/* File: public/styles.css */
:root {
  --background: #ffffff;
  --surface: #f5f7fa;
  --surface-strong: #ffffff;
  --border: #c8d1dc;
  --text: #111827;
  --muted: #374151;
  --link: #0f172a;
  --focus: #111827;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}

* { box-sizing: border-box; }
html { font-size: 100%; }

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 1rem;
  line-height: 1.6;
}

img { max-width: 100%; height: auto; }

a {
  color: var(--link);
  text-underline-offset: 0.18em;
}

a:hover { text-decoration-thickness: 0.14em; }

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 0.25rem;
}

.container {
  width: min(100% - 2rem, 70rem);
  margin: 0 auto;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: 1rem;
  transform: translateY(-200%);
  background: #ffffff;
  color: var(--text);
  border: 2px solid var(--focus);
  padding: 0.75rem 1rem;
  z-index: 1000;
}

.skip-link:focus { transform: translateY(0); }

.site-header {
  border-bottom: 1px solid var(--border);
  padding: 2rem 0;
}

.site-logo {
  display: block;
  margin-bottom: 1rem;
  width: 220px;
  height: auto;
}

h1, h2, h3 {
  line-height: 1.3;
  margin-top: 0;
}

h1 { font-size: 2rem; margin-bottom: 0.5rem; }
h2 { font-size: 1.5rem; margin-bottom: 0.75rem; }
h3 { font-size: 1.125rem; margin-bottom: 0.5rem; }

.site-intro {
  margin: 0;
  color: var(--muted);
  max-width: 60ch;
}

.site-nav {
  border-bottom: 1px solid var(--border);
  background: var(--surface-strong);
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  list-style: none;
  margin: 0;
  padding: 1rem 0;
}

.nav-list a { font-weight: 600; }

.main-content { padding: 2rem 0 3rem; }

.info-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1rem 1.25rem;
  box-shadow: var(--shadow);
  margin-top: 1.5rem;
}

.section-header {
  display: flex;
  gap: 1rem;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}

.secondary-button {
  background: #ffffff;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.625rem 0.875rem;
  cursor: pointer;
  font: inherit;
  font-weight: 600;
}

.secondary-button:hover { background: var(--surface); }

.status-message {
  margin-bottom: 1rem;
  font-size: 1rem;
}

.tree {
  display: grid;
  gap: 1rem;
}

.tree details {
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  background: var(--surface-strong);
  box-shadow: var(--shadow);
}

.tree .level-1 { padding: 1rem; }

.tree .level-2,
.tree .level-3 {
  margin-top: 0.75rem;
  margin-left: 1rem;
  padding: 0.875rem;
  border-left: 3px solid var(--border);
}

.tree summary {
  cursor: pointer;
  font-weight: 700;
}

.tree .level-2 > summary { font-size: 1.125rem; }
.tree .level-3 > summary { font-size: 1rem; }

.file-list {
  list-style: none;
  padding: 0;
  margin: 0.85rem 0 0;
  display: grid;
  gap: 0.5rem;
}

.file-link {
  display: inline-block;
  font-weight: 600;
}

.empty-message {
  margin: 0;
  color: var(--muted);
}

.site-footer {
  margin-top: 2rem;
}

@media (max-width: 40rem) {
  body { font-size: 1.0625rem; }
  h1 { font-size: 1.75rem; }
  .container { width: min(100% - 1rem, 70rem); }
}