/* Article page styles — The Mechanical Researcher */

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

html {
  scroll-padding-top: 3.5rem;
}

body {
  font-family: 'IBM Plex Sans Condensed', sans-serif;
  background: #f5f0e8;
  color: #2c2420;
  line-height: 1.7;
}

.top-bar {
  position: sticky;
  top: 0;
  padding: 0.75rem 1.5rem;
  background: rgba(245, 240, 232, 0.95);
  backdrop-filter: blur(4px);
  border-bottom: 1px solid #d4c9b8;
  z-index: 10;
}

.back-link {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.85rem;
  color: #6b5b4a;
  text-decoration: none;
}

.back-link:hover {
  color: #2c2420;
}

.research-article {
  max-width: 42rem;
  margin: 3rem auto;
  padding: 0 1.5rem;
}

.research-article header {
  margin-bottom: 2.5rem;
}

.article-category {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #8b7a68;
}

.research-article h1 {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 2.25rem;
  font-weight: 600;
  line-height: 1.2;
  margin-top: 0.5rem;
  color: #1a1512;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 0.75rem;
}

.research-article time {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.8rem;
  color: #8b7a68;
}

.permalink {
  font-size: 0.85rem;
  text-decoration: none;
  color: #8b7a68;
  opacity: 0.6;
  transition: opacity 0.15s ease;
  cursor: pointer;
  line-height: 1;
}

.permalink:hover {
  opacity: 1;
}

.permalink.copied {
  color: #5a8a5a;
  opacity: 1;
}

.article-revised {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  color: #8b7355;
}

.article-revised time {
  font-size: inherit;
}

.source-zip {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.8rem;
  color: #6b5b4a;
  text-decoration: none;
  border: 1px solid #2c2420;
  border-radius: 3px;
  padding: 0.15rem 0.5rem;
  background: #fffef7;
}

.source-zip:hover {
  background: #f0e8d8;
}

.article-body h2 {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 1.4rem;
  font-weight: 600;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
  color: #1a1512;
}

.article-body p {
  margin-bottom: 1.25rem;
}

.article-body code {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.9em;
  background: #e8e0d4;
  padding: 0.15em 0.35em;
  border-radius: 3px;
}

.article-body pre {
  background: #2c2420;
  color: #f5f0e8;
  padding: 1.25rem;
  border-radius: 8px;
  overflow-x: auto;
  margin-bottom: 1.25rem;
}

.article-body pre code {
  background: none;
  padding: 0;
  color: inherit;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.25rem;
  font-size: 0.95em;
}

.article-body th,
.article-body td {
  padding: 0.5rem 0.75rem;
  border: 1px solid #d4c9b8;
  text-align: left;
}

.article-body th {
  background: #e8e0d4;
  font-family: 'IBM Plex Sans', sans-serif;
  font-weight: 600;
  font-size: 0.85em;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: #4a3f35;
}

.article-body tbody tr:nth-child(even) {
  background: rgba(232, 224, 212, 0.3);
}

.article-body svg,
.article-body img {
  display: block;
  width: 100%;
  height: auto;
  margin: 1.25rem auto;
  cursor: zoom-in;
}

/* --- Image lightbox --- */

.img-lightbox {
  position: fixed;
  inset: 0;
  z-index: 100;
  background: rgba(44, 36, 32, 0.85);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: zoom-out;
}

.img-lightbox img,
.img-lightbox svg {
  max-width: 95vw;
  max-height: 90vh;
  width: auto;
  height: auto;
  cursor: default;
}

/* Shared close button style — matches index page grid/info close buttons */
.close-btn {
  position: fixed;
  top: 1rem;
  right: 1rem;
  z-index: 110;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  border: 1px solid #d4c9b8;
  background: #fffef7;
  color: #4a3f35;
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.close-btn:hover {
  background: #f0e8d8;
}

/* --- Table of Contents (checkbox hack, no JS) --- */

.toc-state {
  display: none;
}

.toc-btn,
.toc-close {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 20;
  padding: 0.4rem 0.85rem;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  background: #fffef7;
  color: #2c2420;
  border: 1px solid #2c2420;
  border-radius: 4px;
  cursor: pointer;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

.toc-btn:hover,
.toc-close:hover {
  background: #f0e8d8;
}

/* Hide close label, show open label by default */
.toc-close {
  display: none;
}

/* When checked: hide open label, show close label and panel */
.toc-state:checked ~ .toc-btn {
  display: none;
}

.toc-state:checked ~ .toc-close {
  display: block;
  border-radius: 50%;
  padding: 0;
  width: 1.5rem;
  height: 1.5rem;
  font-size: 0.9rem;
  line-height: 1;
  text-align: center;
}

.toc-panel {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 19;
  max-width: 20rem;
  max-height: 70vh;
  overflow-y: auto;
  background: #fffef7;
  border: 1px solid #2c2420;
  border-radius: 4px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.15);
  display: none;
}

.toc-state:checked ~ .toc-panel {
  display: block;
}

.toc-header {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid #d4c9b8;
}

.toc-header span {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  color: #8b7a68;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.toc-list {
  list-style: none;
  padding: 0.5rem 0;
}

.toc-list a {
  display: block;
  padding: 0.3rem 0.75rem;
  font-family: 'IBM Plex Sans Condensed', sans-serif;
  font-size: 0.85rem;
  color: #4a3f35;
  text-decoration: none;
}

.toc-list a:hover {
  background: #f0e8d8;
  color: #1a1512;
}

.bottom-bar {
  text-align: center;
  padding: 1.5rem;
  border-top: 1px solid #d4c9b8;
  margin-top: 4rem;
}

.bottom-bar .site-title {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  color: #8b7a68;
}

/* --- Mobile adjustments --- */

@media (max-width: 600px) {
  .research-article {
    margin: 1.5rem auto;
    padding: 0 1rem;
  }

  .research-article h1 {
    font-size: 1.5rem;
  }

  .article-body h2 {
    font-size: 1.15rem;
    margin-top: 1.75rem;
  }

  .article-body pre {
    padding: 0.75rem;
    font-size: 0.8em;
  }

  .article-body table {
    font-size: 0.8em;
  }

  .article-body th,
  .article-body td {
    padding: 0.35rem 0.5rem;
  }

  .top-bar {
    padding: 0.5rem 1rem;
  }
}