/* ===========================================
   Custom CSS for added features:
   - TOC (Table of Contents)
   - Reading Progress Bar
   - Back to Top Button
   - Search Overlay
   - Tag Filter
   - Certificate Image
   =========================================== */

/* ---- Reading Progress Bar ---- */
.reading-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 10000;
  background: transparent;
}
.reading-progress-fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #6a5acd, #4ecdc4);
  transition: width 0.1s linear;
}

/* ---- Table of Contents ---- */
.toc {
  background: var(--toc-bg, #f8f9fa);
  border: 1px solid var(--toc-border, #e9ecef);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
}
[data-theme="dark"] .toc {
  --toc-bg: #1e1e2e;
  --toc-border: #313244;
}
.toc__header {
  margin-bottom: 0.5rem;
}
.toc__title {
  font-size: 0.95rem;
  font-weight: 700;
  margin: 0;
  color: var(--text-color, #333);
}
.toc__nav {
  font-size: 0.9rem;
}
.toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.toc__item {
  margin: 0.25rem 0;
}
.toc__item--h3 {
  padding-left: 1.25rem;
}
.toc__link {
  color: #6a5acd;
  text-decoration: none;
  border-bottom: none;
  transition: color 0.2s;
}
.toc__link:hover,
.toc__link.active {
  color: #4ecdc4;
}
[data-theme="dark"] .toc__link {
  color: #b4befe;
}
[data-theme="dark"] .toc__link:hover,
[data-theme="dark"] .toc__link.active {
  color: #94e2d5;
}

/* Heading anchor links */
.heading-anchor {
  font-size: 0.7em;
  margin-left: 0.5em;
  opacity: 0;
  transition: opacity 0.2s;
  color: #6a5acd;
  text-decoration: none;
}
h2:hover .heading-anchor,
h3:hover .heading-anchor {
  opacity: 0.6;
}
.heading-anchor:hover {
  opacity: 1 !important;
}

/* ---- Back to Top Button ---- */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: #6a5acd;
  color: #fff;
  border: none;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all 0.3s ease;
  z-index: 9999;
  font-size: 1rem;
  box-shadow: 0 2px 12px rgba(106, 90, 205, 0.35);
  display: flex;
  align-items: center;
  justify-content: center;
}
.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.back-to-top:hover {
  background: #4ecdc4;
  transform: translateY(-3px);
  box-shadow: 0 4px 16px rgba(78, 205, 196, 0.4);
}

/* ---- Search Overlay ---- */
.search-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.6);
  z-index: 10001;
  display: none;
  align-items: flex-start;
  justify-content: center;
  padding-top: 15vh;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}
.search-overlay.is-visible {
  display: flex;
}
.search-overlay__inner {
  width: 90%;
  max-width: 640px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
  overflow: hidden;
}
[data-theme="dark"] .search-overlay__inner {
  background: #1e1e2e;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}
.search-overlay__header {
  display: flex;
  align-items: center;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid #e9ecef;
}
[data-theme="dark"] .search-overlay__header {
  border-bottom-color: #313244;
}
.search-input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 1.15rem;
  padding: 0.5rem;
  background: transparent;
  color: inherit;
}
.search-close-btn {
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  color: #999;
  padding: 0.5rem;
  transition: color 0.2s;
}
.search-close-btn:hover {
  color: #333;
}
[data-theme="dark"] .search-close-btn:hover {
  color: #ccc;
}
.search-results {
  max-height: 50vh;
  overflow-y: auto;
  padding: 1rem 1.25rem;
}
.search-hint,
.search-no-results,
.search-error {
  color: #999;
  text-align: center;
  padding: 2rem 0;
}
.search-results-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.search-result-item {
  margin-bottom: 0.75rem;
}
.search-result-link {
  display: block;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  text-decoration: none;
  transition: background 0.2s;
}
.search-result-link:hover {
  background: #f0f0f5;
}
[data-theme="dark"] .search-result-link:hover {
  background: #313244;
}
.search-result-title {
  display: block;
  font-weight: 600;
  font-size: 1.05rem;
  color: #333;
  margin-bottom: 0.2rem;
}
[data-theme="dark"] .search-result-title {
  color: #cdd6f4;
}
.search-result-date {
  display: inline-block;
  font-size: 0.8rem;
  color: #999;
  margin-bottom: 0.3rem;
}
.search-result-excerpt {
  display: block;
  font-size: 0.85rem;
  color: #666;
  line-height: 1.5;
}
[data-theme="dark"] .search-result-excerpt {
  color: #a6adc8;
}
.search-result-excerpt mark {
  background: #f9e78b;
  color: #333;
  padding: 0 2px;
  border-radius: 2px;
}
[data-theme="dark"] .search-result-excerpt mark {
  background: #f9e78b88;
  color: #cdd6f4;
}

/* ---- Tag Filter ---- */
.tag-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid #e9ecef;
}
[data-theme="dark"] .tag-filter {
  border-bottom-color: #313244;
}
.tag-filter__btn {
  padding: 0.35rem 0.9rem;
  border: 1px solid #ddd;
  border-radius: 20px;
  background: transparent;
  color: #666;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.2s;
}
.tag-filter__btn:hover {
  border-color: #6a5acd;
  color: #6a5acd;
}
.tag-filter__btn.active {
  background: #6a5acd;
  color: #fff;
  border-color: #6a5acd;
}
[data-theme="dark"] .tag-filter__btn {
  border-color: #45475a;
  color: #a6adc8;
}
[data-theme="dark"] .tag-filter__btn:hover {
  border-color: #b4befe;
  color: #b4befe;
}
[data-theme="dark"] .tag-filter__btn.active {
  background: #b4befe;
  color: #1e1e2e;
  border-color: #b4befe;
}

/* ---- Certificate Image ---- */
.certificate-figure {
  margin: 1.5rem 0;
  text-align: center;
}
.certificate-img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
}
.page__award {
  font-size: 1.1rem;
  color: #6a5acd;
  margin-bottom: 0.5rem;
}
[data-theme="dark"] .page__award {
  color: #cba6f7;
}

/* ---- Search toggle icon ---- */
.search-toggle a {
  cursor: pointer;
}

/* ---- PDF Badge (in listing) ---- */
.pdf-badge {
  display: inline-block;
  color: #e74c3c;
  font-size: 0.9em;
  margin-right: 0.3em;
  vertical-align: middle;
}

/* ---- Pin Badge (in listing) ---- */
.pin-badge {
  font-size: 0.85em;
  margin-right: 0.2em;
  vertical-align: middle;
}
.archive__item-container--pinned {
  background: linear-gradient(135deg, rgba(106, 90, 205, 0.04) 0%, rgba(78, 205, 196, 0.04) 100%);
  border-left: 3px solid #6a5acd;
  padding-left: 12px;
  border-radius: 0 8px 8px 0;
  margin-bottom: 0.5rem;
}
[data-theme="dark"] .archive__item-container--pinned {
  background: linear-gradient(135deg, rgba(180, 190, 254, 0.06) 0%, rgba(148, 226, 213, 0.06) 100%);
  border-left-color: #b4befe;
}

/* ---- PDF Viewer ---- */
.pdf-viewer {
  margin: 0 0 1.5rem 0;
  border: 1px solid #e9ecef;
  border-radius: 8px;
  overflow: hidden;
}
[data-theme="dark"] .pdf-viewer {
  border-color: #313244;
}
.pdf-viewer__toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 1rem;
  background: #f8f9fa;
  border-bottom: 1px solid #e9ecef;
}
[data-theme="dark"] .pdf-viewer__toolbar {
  background: #181825;
  border-bottom-color: #313244;
}
.pdf-viewer__badge {
  font-size: 0.9rem;
  font-weight: 600;
  color: #e74c3c;
}
.pdf-viewer__badge i {
  margin-right: 0.3em;
}
.pdf-viewer__container {
  position: relative;
  width: 100%;
  padding-top: min(75%, calc(100vh - 300px));
}
.pdf-viewer__iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
  background: #f0f0f0;
}
.pdf-viewer__description {
  padding: 1rem;
  background: #f8f9fa;
  border-top: 1px solid #e9ecef;
  font-size: 0.9rem;
  color: #666;
}
[data-theme="dark"] .pdf-viewer__description {
  background: #181825;
  border-top-color: #313244;
  color: #a6adc8;
}

/* ---- Responsive adjustments ---- */
@media (max-width: 768px) {
  .toc {
    padding: 0.75rem 1rem;
  }
  .search-overlay__inner {
    width: 95%;
    margin: 0 10px;
  }
  .search-overlay {
    padding-top: 10vh;
  }
  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 38px;
    height: 38px;
  }
}

/* ---- Code Copy Button ---- */
.code-block-wrapper {
  position: relative;
}
.code-copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 4px 10px;
  font-size: 0.8rem;
  background: rgba(128, 128, 128, 0.15);
  color: #666;
  border: 1px solid rgba(128, 128, 128, 0.2);
  border-radius: 6px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.2s, background 0.2s, color 0.2s;
  z-index: 1;
}
.code-block-wrapper:hover .code-copy-btn {
  opacity: 1;
}
.code-copy-btn:hover {
  background: #6a5acd;
  color: #fff;
  border-color: #6a5acd;
}
.code-copy-btn.copied {
  opacity: 1;
  background: #27ae60;
  color: #fff;
  border-color: #27ae60;
}
[data-theme="dark"] .code-copy-btn {
  color: #a6adc8;
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.12);
}
[data-theme="dark"] .code-copy-btn:hover {
  background: #b4befe;
  color: #1e1e2e;
}
[data-theme="dark"] .code-copy-btn.copied {
  background: #a6e3a1;
  color: #1e1e2e;
}

/* ---- Image Lightbox ---- */
.lightbox-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.85);
  z-index: 10002;
  display: none;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.lightbox-overlay.is-visible {
  display: flex;
}
.lightbox-inner {
  position: relative;
  max-width: 95vw;
  max-height: 95vh;
}
.lightbox-inner img {
  max-width: 95vw;
  max-height: 95vh;
  object-fit: contain;
  border-radius: 4px;
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.3);
}
.lightbox-close {
  position: absolute;
  top: -40px;
  right: -40px;
  width: 36px;
  height: 36px;
  border: none;
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
  font-size: 1.5rem;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}
.lightbox-close:hover {
  background: rgba(255, 255, 255, 0.4);
}
@media (max-width: 768px) {
  .lightbox-close {
    top: -36px;
    right: 0;
  }
}

/* ---- Series Navigation ---- */
.series-nav {
  background: var(--toc-bg, #f8f9fa);
  border: 1px solid var(--toc-border, #e9ecef);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
}
[data-theme="dark"] .series-nav {
  --toc-bg: #1e1e2e;
  --toc-border: #313244;
}
.series-nav__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid #e9ecef;
}
[data-theme="dark"] .series-nav__header {
  border-bottom-color: #313244;
}
.series-nav__label {
  font-size: 0.95rem;
  color: #333;
}
[data-theme="dark"] .series-nav__label {
  color: #cdd6f4;
}
.series-nav__count {
  font-size: 0.8rem;
  color: #6a5acd;
  font-weight: 600;
}
.series-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.series-nav__item {
  padding: 0.35rem 0;
  font-size: 0.9rem;
}
.series-nav__item a {
  color: #6a5acd;
  text-decoration: none;
  transition: color 0.2s;
}
.series-nav__item a:hover {
  color: #4ecdc4;
}
[data-theme="dark"] .series-nav__item a {
  color: #b4befe;
}
.series-nav__current {
  font-weight: 700;
  color: #333;
}
[data-theme="dark"] .series-nav__current {
  color: #cdd6f4;
}
.series-nav__footer {
  display: flex;
  justify-content: space-between;
  margin-top: 0.75rem;
  padding-top: 0.5rem;
  border-top: 1px solid #e9ecef;
  font-size: 0.85rem;
}
[data-theme="dark"] .series-nav__footer {
  border-top-color: #313244;
}
.series-nav__prev a,
.series-nav__next a {
  color: #6a5acd;
  text-decoration: none;
  transition: color 0.2s;
}
.series-nav__prev a:hover,
.series-nav__next a:hover {
  color: #4ecdc4;
}

/* ---- Friends Grid (Blogroll) ---- */
.friends-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}
.friend-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  border: 1px solid #e9ecef;
  border-radius: 10px;
  text-decoration: none;
  transition: transform 0.2s, box-shadow 0.2s;
  background: #fff;
}
.friend-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
  text-decoration: none;
}
[data-theme="dark"] .friend-card {
  background: #1e1e2e;
  border-color: #313244;
}
[data-theme="dark"] .friend-card:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}
.friend-card__avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
}
.friend-card__avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.friend-card__avatar--placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #6a5acd, #4ecdc4);
  color: #fff;
  font-size: 1.2rem;
}
.friend-card__info {
  flex: 1;
  min-width: 0;
}
.friend-card__name {
  margin: 0;
  font-size: 0.95rem;
  font-weight: 600;
  color: #333;
}
[data-theme="dark"] .friend-card__name {
  color: #cdd6f4;
}
.friend-card__desc {
  margin: 0.2rem 0 0;
  font-size: 0.8rem;
  color: #888;
  line-height: 1.4;
}

/* ---- Page Views Counter ---- */
.page__views {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: #999;
}
.page__views i {
  margin-right: 0.2em;
}

/* ---- Responsive Images ---- */
.page__content img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1.2rem auto;
  border-radius: 6px;
}
.page__content img:not([src*="svg"]) {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}
[data-theme="dark"] .page__content img:not([src*="svg"]) {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* Ensure tables are scrollable on mobile */
.page__content table {
  display: block;
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

/* Responsive embeds (YouTube, etc.) */
.page__content iframe[src*="youtube"],
.page__content iframe[src*="bilibili"] {
  max-width: 100%;
  aspect-ratio: 16/9;
  height: auto;
}

/* Responsive video */
.page__content video {
  max-width: 100%;
  height: auto;
}

/* ---- Share Buttons: WeChat / QQ / Weibo ---- */
.btn--wechat {
  background: #07c160;
  color: #fff !important;
}
.btn--wechat:hover {
  background: #06ad56;
}
.btn--qq {
  background: #12b7f5;
  color: #fff !important;
}
.btn--qq:hover {
  background: #0fa5dd;
}
.btn--weibo {
  background: #e6162d;
  color: #fff !important;
}
.btn--weibo:hover {
  background: #cf1428;
}

/* ---- Compact Footer ---- */
.page__footer {
  margin-top: 2em;
  padding: 0;
  border-top: 1px solid var(--global-dark-border-color);
}

.page__footer footer {
  margin-top: 0;
  margin-bottom: 0;
  padding: 0.6em 1em;
}

.page__footer-copyright {
  text-align: center;
  font-size: 0.75rem;
  color: var(--global-text-color-light);
  opacity: 0.8;
}

.page__footer-copyright a {
  color: inherit;
  text-decoration: none;
}

.page__footer-copyright a:hover {
  text-decoration: underline;
  opacity: 1;
}

/* ---- Reading Experience Improvements ---- */
.page__content {
  font-size: 1.05em;
  line-height: 1.8;
}

.page__content p {
  margin-bottom: 1.5em;
}

/* Push sidebar to the left of the main content area,
   keeping it within the viewport with a comfortable margin */
@media screen and (min-width: 1024px) {
  .sidebar {
    /* Clamp prevents sidebar from going off-screen left or overlapping content */
    left: clamp(1.2rem, calc((100vw - 1280px) / 2 - 240px), 8rem);
  }
}
@media screen and (min-width: 1024px) and (max-width: 1580px) {
  .sidebar {
    left: 1.5rem;
  }
}

/* ---- Blog archive titles: larger + hover color + distinct base color ---- */
.archive__item-title {
  font-size: 1.35em !important;
}
.archive__item-title a {
  transition: color 0.2s ease;
  color: #222 !important;
}
.archive__item-title a:hover {
  color: #6a5acd !important;
  text-decoration: underline !important;
}
[data-theme="dark"] .archive__item-title a {
  color: #cdd6f4 !important;
}
[data-theme="dark"] .archive__item-title a:hover {
  color: #b4befe !important;
}

/* ---- Sidebar author name: match archive title size ---- */
.sidebar .author__name {
  font-size: 1.35em !important;
  font-weight: 700;
}

/* ---- Sidebar English name below Chinese name ---- */
.sidebar .author__english-name {
  margin: -2px 0 10px 0;
  font-size: 0.85em;
  color: #666;
  font-family: $sans-serif;
}
[data-theme="dark"] .sidebar .author__english-name {
  color: #a0a0a0;
}

/* Wider PDF viewer */
.pdf-viewer__iframe {
  min-height: 600px;
}

@media screen and (min-width: 1280px) {
  .pdf-viewer__iframe {
    min-height: 800px;
  }
}