/* 墨批官网共享样式
   设计基调：宣纸底 + 墨色字 + 朱红点缀，面向「作文批改」这一件事。
   单文件、零依赖、零外部字体请求，保证首屏速度。 */

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

:root {
  --paper: #F5F0E6;
  --ink: #2B2523;
  --red: #C41E3A;
  --ink-light: #7A7168;
  --paper-dark: #EBE4D6;
  --rule: #DCD3C2;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body {
  font-family: "LXGW WenKai", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--paper);
  color: var(--ink);
  line-height: 1.8;
}

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

a {
  color: var(--red);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===== 顶栏 ===== */
.site-header {
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 20px;
  padding-top: 16px;
  padding-bottom: 16px;
}

.brand {
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 4px;
  color: var(--ink);
}

.brand:hover {
  text-decoration: none;
}

.brand span {
  font-size: 0.8125rem;
  font-weight: 400;
  letter-spacing: 1px;
  color: var(--ink-light);
  margin-left: 10px;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 18px;
  font-size: 0.875rem;
}

.site-nav a {
  color: var(--ink-light);
  letter-spacing: 1px;
}

.site-nav a[aria-current="page"] {
  color: var(--red);
}

/* ===== Hero ===== */
.hero {
  padding: 72px 0 64px;
  text-align: center;
}

.hero-brand {
  font-size: 3.5rem;
  font-weight: 600;
  letter-spacing: 12px;
  /* letter-spacing 会在末字右侧留白，抵消掉才能视觉居中 */
  margin-right: -12px;
  color: var(--ink);
  margin-bottom: 8px;
}

.hero-line {
  display: block;
  width: 56px;
  height: 1px;
  background: var(--red);
  margin: 0 auto 32px;
}

.hero-slogan {
  font-size: 1.25rem;
  font-weight: 400;
  letter-spacing: 3px;
  color: var(--ink-light);
  line-height: 2.2;
}

.hero-keywords {
  margin-top: 20px;
  font-size: 0.9375rem;
  letter-spacing: 2px;
  color: var(--ink-light);
}

.hero-qr {
  margin-top: 28px;
}

.hero-qr img {
  display: block;
  margin: 0 auto;
  border-radius: 4px;
}

/* ===== 通用区块 ===== */
.section {
  padding: 64px 0;
}

.section-alt {
  background: var(--paper-dark);
}

.section-title {
  text-align: center;
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: 4px;
  margin-right: -4px;
  margin-bottom: 40px;
}

.section-lead {
  max-width: 720px;
  margin: -24px auto 40px;
  text-align: center;
  font-size: 0.9375rem;
  color: var(--ink-light);
}

/* ===== 使用流程 ===== */
.flow-steps {
  display: flex;
  justify-content: center;
  gap: 24px;
}

.flow-step {
  flex: 1;
  max-width: 240px;
  text-align: center;
  padding: 32px 16px;
}

.flow-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 20px;
}

.flow-icon svg {
  width: 100%;
  height: 100%;
  stroke: var(--ink);
  fill: none;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.flow-step h3 {
  font-size: 1.1rem;
  font-weight: 500;
  letter-spacing: 2px;
  margin-bottom: 8px;
}

.flow-step p {
  font-size: 0.875rem;
  color: var(--ink-light);
  line-height: 1.8;
}

.flow-arrow {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  padding-top: 20px;
}

.flow-arrow svg {
  width: 24px;
  height: 24px;
  stroke: var(--ink-light);
  fill: none;
  stroke-width: 1.5;
}

/* ===== 效果展示 ===== */
.showcase-track {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

.showcase-phone {
  width: 200px;
  flex-shrink: 0;
}

.showcase-frame {
  position: relative;
  background: #1a1a1a;
  border-radius: 24px;
  padding: 10px 10px 28px;
  box-shadow: 0 4px 20px rgba(43, 37, 35, 0.15);
}

.showcase-frame::before {
  content: '';
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  width: 48px;
  height: 4px;
  background: #333;
  border-radius: 2px;
}

.showcase-frame img {
  width: 100%;
  border-radius: 12px;
  display: block;
}

.showcase-caption {
  text-align: center;
  font-size: 0.8125rem;
  color: var(--ink-light);
  letter-spacing: 1px;
  margin-top: 12px;
}

/* ===== 特性卡片 ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.feature-card {
  padding: 28px 24px;
  background: var(--paper-dark);
  border-radius: 4px;
}

.section-alt .feature-card {
  background: var(--paper);
}

.feature-card h3 {
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 2px;
  margin-bottom: 8px;
  padding-left: 12px;
  border-left: 2px solid var(--red);
}

.feature-card p {
  font-size: 0.875rem;
  color: var(--ink-light);
  line-height: 1.8;
  padding-left: 14px;
}

/* ===== 受众 ===== */
.audience-list {
  max-width: 560px;
  margin: 0 auto;
}

.audience-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--rule);
}

.audience-item:last-child {
  border-bottom: none;
}

.audience-dot {
  width: 6px;
  height: 6px;
  margin-top: 10px;
  border-radius: 50%;
  background: var(--red);
  flex-shrink: 0;
}

.audience-item h3 {
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 1px;
  margin-bottom: 2px;
}

.audience-item p {
  font-size: 0.875rem;
  color: var(--ink-light);
}

/* ===== 内容页 ===== */
.breadcrumb {
  padding: 20px 0 0;
  font-size: 0.8125rem;
  color: var(--ink-light);
  letter-spacing: 1px;
}

.breadcrumb a {
  color: var(--ink-light);
}

.breadcrumb span {
  color: var(--ink);
}

.page {
  padding: 32px 0 56px;
}

.article {
  max-width: 720px;
}

.article h1 {
  font-size: 1.875rem;
  font-weight: 600;
  line-height: 1.5;
  letter-spacing: 1px;
  margin-bottom: 16px;
}

.article .lead {
  font-size: 1rem;
  color: var(--ink-light);
  padding-bottom: 24px;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 32px;
}

.article h2 {
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: 1px;
  margin: 40px 0 16px;
  padding-left: 12px;
  border-left: 3px solid var(--red);
  line-height: 1.6;
}

.article h3 {
  font-size: 1.0625rem;
  font-weight: 500;
  margin: 28px 0 10px;
}

.article p {
  margin-bottom: 16px;
}

.article ul,
.article ol {
  margin: 0 0 16px 22px;
}

.article li {
  margin-bottom: 8px;
}

.article strong {
  font-weight: 600;
}

.article table {
  width: 100%;
  border-collapse: collapse;
  margin: 8px 0 24px;
  font-size: 0.875rem;
  line-height: 1.7;
}

.article th,
.article td {
  border: 1px solid var(--rule);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}

.article th {
  background: var(--paper-dark);
  font-weight: 500;
  white-space: nowrap;
}

.article .note {
  padding: 16px 20px;
  background: var(--paper-dark);
  border-left: 3px solid var(--red);
  border-radius: 0 4px 4px 0;
  font-size: 0.9375rem;
  color: var(--ink);
  margin: 0 0 24px;
}

.article .note p:last-child {
  margin-bottom: 0;
}

/* FAQ：无 JS 折叠，正文照样在 HTML 里，爬虫读得到 */
.faq-item {
  border-bottom: 1px solid var(--rule);
  padding: 14px 0;
}

.faq-item summary {
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 1px;
  list-style: none;
  position: relative;
  padding-left: 22px;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::before {
  content: '问';
  position: absolute;
  left: 0;
  top: 0;
  font-size: 0.75rem;
  color: var(--red);
  line-height: 2.1;
}

.faq-item[open] summary {
  margin-bottom: 10px;
}

.faq-item p {
  font-size: 0.9375rem;
  color: var(--ink-light);
  padding-left: 22px;
  margin-bottom: 0;
}

/* ===== 相关阅读 ===== */
.related {
  margin-top: 48px;
  padding-top: 28px;
  border-top: 1px solid var(--rule);
}

.related h2 {
  font-size: 1.0625rem;
  font-weight: 500;
  border: none;
  padding: 0;
  margin: 0 0 14px;
}

.related ul {
  list-style: none;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px 24px;
  font-size: 0.9375rem;
}

/* ===== CTA ===== */
.cta {
  padding: 72px 0;
  text-align: center;
  background: var(--paper-dark);
}

.cta-title {
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: 3px;
  margin-bottom: 12px;
}

.cta-sub {
  font-size: 0.9375rem;
  color: var(--ink-light);
  margin-bottom: 28px;
}

.qr-box {
  width: 180px;
  height: 180px;
  margin: 0 auto 20px;
  border-radius: 4px;
  overflow: hidden;
}

.qr-box img {
  width: 100%;
  height: 100%;
  display: block;
}

.cta-hint {
  font-size: 0.875rem;
  color: var(--ink-light);
  letter-spacing: 1px;
}

/* ===== 页脚 ===== */
footer {
  padding: 36px 0;
  text-align: center;
  font-size: 0.75rem;
  color: var(--ink-light);
  letter-spacing: 1px;
  line-height: 2;
}

.footer-nav {
  margin-bottom: 12px;
  font-size: 0.8125rem;
}

.footer-nav a {
  color: var(--ink-light);
  margin: 0 8px;
  white-space: nowrap;
}

/* ===== 移动端 ===== */
@media (max-width: 767px) {
  .hero {
    padding: 48px 0 40px;
  }

  .hero-brand {
    font-size: 2.5rem;
    letter-spacing: 8px;
    margin-right: -8px;
  }

  .hero-slogan {
    font-size: 1.0625rem;
    letter-spacing: 2px;
  }

  .flow-steps {
    flex-direction: column;
    align-items: center;
    gap: 0;
  }

  .flow-step {
    max-width: 280px;
    padding: 20px 16px;
  }

  .flow-arrow {
    transform: rotate(90deg);
    width: auto;
    padding: 0;
    margin: -4px 0;
  }

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

  .showcase-track {
    gap: 16px;
  }

  .showcase-phone {
    width: 150px;
  }

  .section-title {
    letter-spacing: 2px;
    margin-right: -2px;
  }

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

  .article table {
    font-size: 0.8125rem;
  }

  .article th,
  .article td {
    padding: 8px;
  }

  .related ul {
    grid-template-columns: 1fr;
  }

  .cta {
    padding: 56px 0;
  }
}