:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --card: #ffffff;
  --border: #e2e8f0;
  --accent: #b45309;
  --accent2: #1d4ed8;
  --text: #1e293b;
  --muted: #64748b;
  --green: #15803d;
}

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

body {
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: "DM Sans", sans-serif;
}

header {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 0 1.5rem;
  border-bottom: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(12px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1100px;
  height: 62px;
  margin: auto;
}

.logo {
  color: var(--text);
  font-family: "Playfair Display", serif;
  font-size: 1.5rem;
  font-weight: 900;
  text-decoration: none;
}

.logo-image {
  width: 2rem;
  height: 2rem;
  object-fit: contain;
  vertical-align: middle;
}

.logo span {
  color: var(--accent);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.2rem;
}

.nav-menu a {
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 500;
  text-decoration: none;
  transition: color 0.2s;
}

.nav-menu a:hover,
.nav-menu a.active {
  color: var(--accent);
}

.wrap {
  display: grid;
  grid-template-columns: 1fr 290px;
  gap: 2rem;
  max-width: 1100px;
  margin: auto;
  padding: 2.5rem 1.5rem;
}

.breadcrumb {
  margin-bottom: 1.25rem;
  color: var(--muted);
  font-size: 0.77rem;
}

.breadcrumb a,
.fc a,
.toc a {
  color: var(--accent2);
  text-decoration: none;
}

.breadcrumb span {
  margin: 0 0.4rem;
}

.cat-badge {
  display: inline-block;
  margin-bottom: 0.85rem;
  padding: 0.2rem 0.7rem;
  border: 1px solid #e8c98d;
  border-radius: 5px;
  background: #fff4dc;
  color: #8a5a12;
  font-size: 0.67rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

h1 {
  margin-bottom: 1rem;
  font-family: "Playfair Display", serif;
  font-size: 2.1rem;
  font-weight: 900;
  line-height: 1.3;
}

h1 span {
  color: var(--accent);
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.75rem;
  padding: 1rem 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.meta-item {
  color: var(--muted);
  font-size: 0.78rem;
}

.intro {
  margin-bottom: 2rem;
  padding: 1.5rem;
  border: 1px solid #ead9b8;
  border-radius: 12px;
  background: linear-gradient(135deg, #fff8eb, #f2f7fc);
}

.intro p {
  color: var(--text);
  font-size: 0.92rem;
  line-height: 1.82;
}

h2 {
  margin: 2rem 0 0.85rem;
  color: var(--text);
  font-family: "Playfair Display", serif;
  font-size: 1.35rem;
  font-weight: 700;
}

h3 {
  margin: 1.5rem 0 0.65rem;
  color: var(--accent);
  font-size: 1rem;
  font-weight: 700;
}

p {
  margin-bottom: 0.9rem;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.82;
}

ul,
ol {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  margin-bottom: 0.9rem;
  padding-left: 1.4rem;
}

li {
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.7;
}

strong {
  color: var(--text);
}

.qa {
  overflow: hidden;
  margin-bottom: 1rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
}

.qa-q {
  padding: 0.9rem 1.2rem;
  border-bottom: 1px solid var(--border);
  background: #fff8eb;
  color: var(--text);
  font-size: 0.88rem;
  font-weight: 700;
}

.qa-q::before {
  color: var(--accent);
  content: "Q: ";
}

.qa-a {
  padding: 0.9rem 1.2rem;
  color: var(--muted);
  font-size: 0.87rem;
  line-height: 1.75;
}

.java-article .qa-a {
  line-height: 1.8;
}

.qa-a::before {
  color: var(--accent2);
  font-weight: 700;
  content: "A: ";
}

.tip,
.warn,
.info {
  margin: 1.25rem 0;
  padding: 1.2rem 1.4rem;
  border-radius: 10px;
}

.tip {
  border: 1px solid #a9ddc5;
  background: #eef9f3;
}

.warn {
  border: 1px solid #e8c3be;
  background: #fff4f2;
}

.info {
  border: 1px solid #bdd4ea;
  background: #f0f7fd;
}

.tip p,
.warn p,
.info p {
  margin: 0;
  color: var(--text);
  font-size: 0.88rem;
  line-height: 1.75;
}

.checklist {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin: 1.25rem 0;
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
}

.checklist li {
  color: var(--text);
  font-size: 0.88rem;
  line-height: 1.7;
  list-style: none;
}

.checklist li::before {
  content: "✅ ";
}

code {
  padding: 0.1rem 0.4rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: #f1f3f5;
  color: var(--accent);
  font-family: monospace;
  font-size: 0.82rem;
}

pre {
  overflow-x: auto;
  margin: 1rem 0;
  padding: 1rem 1.2rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #f1f3f5;
}

pre code {
  padding: 0;
  border: none;
  background: none;
  color: var(--text);
  font-size: 0.83rem;
  line-height: 1.7;
}

.toc {
  margin-bottom: 2rem;
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--card);
}

.toc h3 {
  margin: 0 0 0.75rem;
  color: var(--text);
  font-size: 0.88rem;
  font-weight: 700;
}

.toc ol {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  padding-left: 1.2rem;
}

.toc li {
  color: var(--muted);
  font-size: 0.82rem;
}

.toc a:hover {
  color: var(--accent);
}

.section-num {
  display: inline-block;
  margin-right: 0.5rem;
  padding: 0.15rem 0.55rem;
  border-radius: 4px;
  background: var(--accent);
  color: #fff;
  font-size: 0.67rem;
  font-weight: 800;
}

.ad-banner {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.3rem;
  min-height: 90px;
  margin: 1.75rem 0;
  padding: 1.2rem;
  border: 1px dashed var(--border);
  border-radius: 10px;
  background: var(--surface);
  color: var(--muted);
  font-size: 0.7rem;
  text-align: center;
}

.ad-label {
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.ad-slot {
  display: block;
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 1.4rem;
}

.widget,
.toc-sticky {
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--card);
}

.widget-header {
  padding: 0.75rem 1.15rem;
  border-bottom: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.widget-body {
  padding: 0.85rem 1.15rem;
}

.sa {
  display: flex;
  gap: 0.7rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--border);
  color: inherit;
  text-decoration: none;
  transition: color 0.2s;
}

.sa:last-child {
  border-bottom: none;
}

.sa:hover {
  color: var(--accent);
}

.sa-icon {
  display: flex;
  flex-shrink: 0;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: #f1f3f5;
  font-size: 0.95rem;
}

.sa-title {
  font-size: 0.79rem;
  font-weight: 600;
  line-height: 1.45;
}

.sa-sub {
  margin-top: 0.15rem;
  color: var(--muted);
  font-size: 0.7rem;
}

.toc-sticky {
  position: sticky;
  top: 75px;
}

.toc-sticky .widget-body {
  overflow-y: auto;
  max-height: 420px;
  padding: 0.85rem 1.15rem;
}

.toc-sticky a {
  display: block;
  padding: 0.35rem 0;
  border-bottom: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.78rem;
  text-decoration: none;
  transition: color 0.2s;
}

.toc-sticky a:last-child {
  border-bottom: none;
}

.toc-sticky a:hover {
  color: var(--accent);
}

.back-to-blog {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-bottom: 1rem;
  color: var(--accent2);
  font-size: 0.83rem;
  font-weight: 500;
  text-decoration: none;
}

.sidebar-promo {
  margin-bottom: 0.85rem;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.7;
}

.social-link {
  display: block;
  padding: 0.6rem;
  border-radius: 8px;
  background: #2563eb;
  color: #fff;
  font-size: 0.82rem;
  font-weight: 700;
  text-align: center;
  text-decoration: none;
}

footer {
  margin-top: 1rem;
  padding: 1.5rem;
  border-top: 1px solid var(--border);
  background: var(--surface);
  text-align: center;
}

.fc {
  color: var(--muted);
  font-size: 0.77rem;
}

@media (max-width: 900px) {
  .wrap {
    grid-template-columns: minmax(0, 1fr);
  }

  .wrap > article,
  .wrap > aside {
    min-width: 0;
  }

  .sidebar {
    order: -1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
  }

  .toc-sticky {
    position: static;
  }
}

@media (max-width: 700px) {
  .nav-menu {
    display: none;
  }

  h1 {
    font-size: 1.6rem;
  }

  .wrap {
    padding: 1.5rem 1rem;
  }

  .sidebar {
    grid-template-columns: 1fr;
  }
}