/* 1. 先让盒子的宽度容易计算。 */
:root {
  color-scheme: light;
  --paper: #f7f5ee;
  --card: #fffef9;
  --ink: #242e27;
  --muted: #626b61;
  --green: #244c3a;
  --line: #d9ddcf;
  --soft-green: #e8ecdf;
  --serif: "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC", "STSong", serif;
}

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

html {
  scroll-padding-top: 1.5rem;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  overflow-wrap: anywhere;
}

a {
  color: var(--green);
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration-thickness: 2px;
}

:focus-visible {
  outline: 3px solid #a1451c;
  outline-offset: 4px;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  line-height: 1.35;
}

.skip-link {
  position: absolute;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 1;
  padding: 0.5rem 1rem;
  color: var(--card);
  background: var(--green);
  transform: translateY(-200%);
}

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

/* 2. 全页共享一条左右边界。 */
.site-header,
.page-intro,
.app-layout,
.site-footer {
  width: min(72rem, calc(100% - 4rem));
  margin-inline: auto;
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 1.75rem;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 700;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 2.6rem;
  height: 2.6rem;
  place-items: center;
  color: var(--paper);
  background: var(--green);
  border-radius: 2px;
  font-size: 1.5rem;
}

.brand-en {
  margin-left: 0.65rem;
  font-family: Georgia, serif;
  font-size: 0.64rem;
  letter-spacing: 0.14em;
}

.header-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  font-size: 0.8rem;
}

.header-nav a {
  padding-block: 0.5rem;
  color: var(--muted);
}

.page-intro {
  padding-block: 4rem 3rem;
}

.eyebrow {
  margin-bottom: 0.75rem;
  color: var(--muted);
  font-family: Georgia, serif;
  font-size: 0.65rem;
  letter-spacing: 0.14em;
}

.page-intro h1 {
  margin-bottom: 0.9rem;
  font-family: var(--serif);
  font-size: clamp(2rem, 5vw, 3.35rem);
  font-weight: 600;
  letter-spacing: -0.04em;
}

.page-intro > p:last-child {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

/* 3. Grid 负责侧栏和资料区的两列布局。 */
.app-layout {
  display: grid;
  grid-template-columns: 14rem minmax(0, 1fr);
  gap: 3rem;
  align-items: start;
}

.sidebar,
.library,
.resource-content {
  min-width: 0;
}

.sidebar {
  padding-top: 0.4rem;
}

.sidebar h2 {
  margin-bottom: 1.25rem;
  font-family: var(--serif);
  font-size: 1.3rem;
}

.sidebar-links,
.resource-list,
.tags {
  margin: 0;
  padding: 0;
  list-style: none;
}

.sidebar-links {
  border-top: 1px solid var(--line);
}

.sidebar-links li {
  border-bottom: 1px solid var(--line);
}

.sidebar-links a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.8rem 0.2rem;
  font-size: 0.875rem;
  text-decoration: none;
}

.sidebar-links a:hover {
  background: var(--soft-green);
}

.sidebar-links span {
  font-family: Georgia, serif;
  font-size: 0.75rem;
}

.reading-counts {
  margin-block: 1.5rem;
  color: var(--muted);
  font-size: 0.8rem;
}

.reading-counts > div {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 0.25rem;
}

.reading-counts dd {
  margin: 0;
  font-family: Georgia, serif;
}

.sidebar-note {
  margin-top: 2.5rem;
  color: var(--muted);
  font-family: var(--serif);
  font-size: 0.9rem;
  line-height: 1.9;
}

.library-heading {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  justify-content: space-between;
  gap: 0.5rem 1rem;
  padding-bottom: 1.4rem;
  border-bottom: 2px solid var(--ink);
}

.library-heading .eyebrow {
  margin-bottom: 0.35rem;
}

.library-heading h2 {
  margin-bottom: 0;
  font-family: var(--serif);
  font-size: 1.9rem;
  font-weight: 600;
}

.total-count {
  margin-bottom: 0.15rem;
  color: var(--muted);
  font-size: 0.8rem;
}

.search-form {
  margin-block: 1.5rem 1.75rem;
}

.search-form label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
}

.search-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

input,
button {
  border: 1px solid var(--green);
  border-radius: 3px;
  font: inherit;
  font-size: 0.875rem;
}

input {
  flex: 1 1 12rem;
  min-width: 0;
  max-width: 100%;
  padding: 0.7rem 0.85rem;
  color: var(--ink);
  background: var(--card);
}

input::placeholder {
  color: var(--muted);
}

button {
  padding: 0.7rem 1.1rem;
  color: var(--card);
  background: var(--green);
  cursor: pointer;
}

button:hover {
  background: #183726;
}

.form-help {
  margin-block: 0.6rem 0;
  color: var(--muted);
  font-size: 0.75rem;
  line-height: 1.6;
}

/* 4. 卡片保持正常文档流，局部排列再使用 Flex。 */
.resource-list {
  display: grid;
  gap: 0.75rem;
}

.resource-card {
  display: flex;
  gap: 1.25rem;
  padding: 1.6rem;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--card);
}

.resource-index {
  flex-shrink: 0;
  padding-top: 0.05rem;
  color: var(--muted);
  font-family: Georgia, serif;
  font-size: 0.75rem;
}

.resource-content {
  flex: 1;
}

.resource-source {
  margin-bottom: 0.35rem;
  color: var(--muted);
  font-family: Georgia, serif;
  font-size: 0.75rem;
}

.resource-card h3 {
  margin-bottom: 0.6rem;
  font-family: var(--serif);
  font-size: 1.35rem;
  font-weight: 600;
}

.resource-card h3 a {
  color: var(--ink);
  text-decoration-thickness: 1px;
  text-decoration-color: var(--line);
}

.resource-card h3 a:hover {
  color: var(--green);
  text-decoration-color: var(--green);
}

.resource-description {
  margin-bottom: 1.15rem;
  color: var(--muted);
  font-size: 0.85rem;
}

.resource-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem 1rem;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.tags li {
  padding: 0.1rem 0.55rem;
  color: var(--green);
  background: var(--soft-green);
  border-radius: 2px;
  font-size: 0.7rem;
}

.status {
  font-size: 0.75rem;
}

.status::before {
  display: inline-block;
  width: 0.4rem;
  height: 0.4rem;
  margin-right: 0.5rem;
  border-radius: 50%;
  background: currentColor;
  content: "";
}

.status-unread {
  color: #735920;
}

.status-reading {
  color: var(--green);
}

.status-archived {
  color: var(--muted);
}

.data-note {
  margin-top: 1.75rem;
  padding: 1rem 0 0 1rem;
  border-left: 2px solid var(--line);
  color: var(--muted);
  font-size: 0.8rem;
}

.data-note h3 {
  margin-bottom: 0.5rem;
  color: var(--ink);
  font-size: 0.85rem;
}

.data-note p {
  margin-bottom: 0;
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem 1rem;
  margin-top: 4rem;
  padding-block: 1.5rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.75rem;
}

.site-footer p {
  margin: 0;
}

/* 5. 空间放不下两列时，改变布局关系。 */
@media (max-width: 48rem) {
  .site-header,
  .page-intro,
  .app-layout,
  .site-footer {
    width: calc(100% - 2rem);
  }

  .app-layout {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .site-header {
    padding-block: 1rem;
  }

  .page-intro {
    padding-block: 2.5rem 2rem;
  }

  .sidebar-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0 1.5rem;
    border-bottom: 1px solid var(--line);
  }

  .sidebar-links li {
    border-bottom: 0;
  }

  .reading-counts {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem 1.5rem;
    margin-bottom: 0;
  }

  .reading-counts > div {
    gap: 0.5rem;
  }

  .sidebar-note {
    margin-block: 1rem 0;
  }

  .resource-card {
    gap: 0.8rem;
    padding: 1.1rem;
  }

  .site-footer {
    margin-top: 2.5rem;
  }
}