/* 移动端优先 · 系统字体 · 单文件极简样式 */
:root {
  --green: #16a34a;
  --green-dark: #15803d;
  --ink: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --bg-soft: #f9fafb;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color: var(--ink);
  background: #fff;
  line-height: 1.6;
}
main { max-width: 880px; margin: 0 auto; padding: 0 16px 48px; }

/* 头部 */
.site-header {
  display: flex; align-items: baseline; justify-content: space-between;
  max-width: 880px; margin: 0 auto; padding: 16px;
}
.logo { font-weight: 700; font-size: 1.15rem; color: var(--green-dark); text-decoration: none; }
.tagline { color: var(--muted); font-size: .85rem; }

/* 首页 hero 与工具卡片 */
.hero { text-align: center; padding: 32px 0 24px; }
.hero h1 { font-size: 1.6rem; margin: 0 0 12px; line-height: 1.3; }
.hero p { color: var(--muted); margin: 0 auto; max-width: 34em; }
.tool-grid { display: grid; gap: 14px; grid-template-columns: 1fr; margin: 24px 0; }
.tool-card {
  border: 1px solid var(--line); border-radius: 10px; padding: 16px;
  text-decoration: none; color: inherit; transition: border-color .15s;
}
.tool-card:hover { border-color: var(--green); }
.tool-card h2 { margin: 6px 0; font-size: 1.05rem; color: var(--green-dark); }
.tool-card p { margin: 0; color: var(--muted); font-size: .88rem; }
.cat {
  display: inline-block; font-size: .72rem; letter-spacing: .04em;
  text-transform: uppercase; color: var(--green-dark);
  background: #dcfce7; border-radius: 99px; padding: 1px 10px;
}

/* 首页信任区 */
.trust h2 { font-size: 1.2rem; text-align: center; }
.trust-grid { display: grid; gap: 16px; grid-template-columns: 1fr; }
.trust-grid h3 { margin: 0 0 4px; font-size: .98rem; }
.trust-grid p { margin: 0; color: var(--muted); font-size: .88rem; }

/* 工具页 */
.crumbs { color: var(--muted); font-size: .85rem; margin: 20px 0 8px; }
.crumbs a { color: var(--green-dark); text-decoration: none; }
.tool-page h1 { font-size: 1.45rem; margin: 0 0 8px; }
.intro { color: var(--muted); margin-top: 0; }

/* 拖拽工作台 */
.workbench { margin: 20px 0; }
#dropzone {
  border: 2px dashed #c7cbd1; border-radius: 12px; background: var(--bg-soft);
  text-align: center; padding: 36px 16px; cursor: pointer; outline: none;
  transition: border-color .15s, background .15s;
}
#dropzone:hover, #dropzone:focus-visible, #dropzone.drag {
  border-color: var(--green); background: #f0fdf4;
}
.dz-icon { margin: 0; font-size: 1.6rem; }
.dz-main { margin: 6px 0 2px; font-weight: 600; }
.dz-sub { margin: 0; color: var(--muted); font-size: .84rem; }

.options { margin: 14px 0; display: flex; flex-wrap: wrap; gap: 18px; }
.opt { display: inline-flex; align-items: center; gap: 8px; font-size: .92rem; }

/* 结果卡片 */
.result-card {
  border: 1px solid var(--line); border-radius: 10px;
  padding: 12px 14px; margin-bottom: 10px; font-size: .92rem;
}
.result-card .row {
  display: flex; flex-wrap: wrap; gap: 6px 14px;
  align-items: center; justify-content: space-between;
}
.size-delta-down { color: var(--green-dark); font-weight: 600; }
.size-delta-up { color: #b45309; font-weight: 600; }
.dim-info { display: block; color: var(--muted); font-size: .8rem; }
.download-btn {
  display: inline-block; background: var(--green); color: #fff;
  border-radius: 8px; padding: 6px 16px; text-decoration: none; font-weight: 600;
}
.download-btn:hover { background: var(--green-dark); }
.error-msg { color: #b91c1c; }

/* 说明与 FAQ */
.howto ol { padding-left: 20px; }
.faq details {
  border-bottom: 1px solid var(--line); padding: 10px 0;
}
.faq summary { cursor: pointer; font-weight: 600; }
.faq p { color: var(--ink); }

/* 页脚 */
.site-footer {
  border-top: 1px solid var(--line); background: var(--bg-soft);
  padding: 24px 16px; text-align: center;
}
.privacy-note { font-size: .88rem; color: var(--green-dark); font-weight: 600; margin: 0 0 12px; }
.footer-nav { display: flex; flex-wrap: wrap; gap: 6px 18px; justify-content: center; margin-bottom: 12px; }
.footer-nav a { color: var(--muted); font-size: .86rem; text-decoration: none; }
.footer-nav a:hover { color: var(--green-dark); }
.copyright { color: var(--muted); font-size: .78rem; margin: 0; }

/* 平板以上双列 */
@media (min-width: 640px) {
  .tool-grid { grid-template-columns: 1fr 1fr; }
  .trust-grid { grid-template-columns: repeat(3, 1fr); }
  .hero h1 { font-size: 2rem; }
}

/* 独立内容页(隐私政策/关于) */
.content-page h1 { margin-bottom: 20px; }
.page-body { max-width: 46em; }
.page-body h2 { font-size: 1.1rem; margin: 26px 0 8px; }
.page-body p { color: var(--ink); }
.page-body ul, .page-body ol { padding-left: 22px; }
.page-body li { margin-bottom: 6px; }

/* footer 次级导航(政策/关于) */
.footer-nav-small { margin-top: 4px; }
.footer-nav-small a { font-size: .8rem; text-decoration: underline; }