/* ==========================================================================
   Binary Code Translator — style.css
   设计 token 提取自 remove.bg 生产 CSS；浅色/暗色双主题（CSS 变量映射）
   装饰全部为 CSS/内联 SVG，动画只动 transform/opacity
   ========================================================================== */

:root {
  --color-primary: #0F70E6;
  --color-primary-pressed: #0C57B2;
  --color-bg: #FFFFFF;
  --color-bg-subtle: #F7F9FA;
  --color-text: #454545;
  --color-text-secondary: #54616C;
  --color-border: #DEE2E6;
  --color-success: #1E7F4F;
  --color-success-bg: #93E3C0;
  --color-error: #F93E3E;
  --color-error-bg: #FDECEC;
  --color-warning-bg: #FFD7A8;
  --color-card-shadow: 0 8px 32px -2px rgba(0, 27, 45, .12);
  --color-card-shadow-hover: 0 18px 48px -6px rgba(0, 27, 45, .18);
  --color-input-bg: #FFFFFF;
  --ease-out: cubic-bezier(.165, .84, .44, 1);
  --glow-primary: rgba(15, 112, 230, .15);
  --font-heading: 'Poppins', sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, 'Liberation Mono', monospace;
  --radius-card: 8px;
  --radius-pill: 99px;
  --header-height: 72px;
  --container: 1152px;
}

[data-theme="dark"] {
  --color-primary: #4C9AFF;
  --color-primary-pressed: #0F70E6;
  --color-bg: #12181D;
  --color-bg-subtle: #1A2229;
  --color-text: #E3E8EC;
  --color-text-secondary: #9FB0BC;
  --color-border: #33404B;
  --color-success: #7ADCB2;
  --color-success-bg: #173B2C;
  --color-error: #FF7A7A;
  --color-error-bg: #3D1B1B;
  --color-warning-bg: #4A3520;
  --color-card-shadow: 0 8px 32px -2px rgba(0, 0, 0, .5);
  --color-card-shadow-hover: 0 18px 48px -6px rgba(0, 0, 0, .65);
  --color-input-bg: #1A2229;
  --glow-primary: rgba(76, 154, 255, .2);
}

/* ---------- 基础 ---------- */

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-text);
  margin: 0 0 1rem;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.15rem; }

p { margin: 0 0 1rem; }

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

code, .mono {
  font-family: var(--font-mono);
  font-size: .925em;
}

:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 4px;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 1rem;
}

.section { padding: 4rem 0; }
.section-alt { background: var(--color-bg-subtle); }

.section-lead {
  color: var(--color-text-secondary);
  max-width: 44rem;
}

/* ---------- 滚动进入视口动画（仅 JS 可用时启用，降级安全） ---------- */

.js .section .container {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .6s var(--ease-out), transform .6s var(--ease-out);
}
.js .section .container.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 区块间波浪分隔带（remove.bg 标志性元素） ---------- */

.wave-divider {
  background: var(--color-bg);
  line-height: 0;
}
.wave-divider svg {
  width: 100%;
  height: 56px;
  display: block;
}
.wave-divider path { fill: var(--color-bg-subtle); }
.wave-divider.wave-to-white { background: var(--color-bg-subtle); }
.wave-divider.wave-to-white path { fill: var(--color-bg); }

/* ---------- 导航 ---------- */

.site-header {
  height: var(--header-height);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: .5rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--color-text);
}
.logo:hover { text-decoration: none; }
.logo svg { flex: none; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-links a {
  color: var(--color-text-secondary);
  font-weight: 600;
  padding: .5rem .75rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  transition: color .15s ease-in-out;
}
.nav-links a:hover { color: var(--color-primary); }

/* ---------- 按钮（药丸形） ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .4rem;
  min-height: 44px;
  padding: .55rem 1.25rem;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font-family: var(--font-body);
  font-size: .925rem;
  font-weight: 700;
  cursor: pointer;
  transition: background .15s ease-in-out, color .15s ease-in-out,
    border-color .15s ease-in-out, transform .15s var(--ease-out), box-shadow .15s ease-in-out;
  background: var(--color-bg-subtle);
  color: var(--color-text);
}

.btn:hover { border-color: var(--color-border); }
.btn:active { transform: scale(.97); }

.btn-primary { background: var(--color-primary); color: #FFFFFF; }
.btn-primary:hover {
  background: var(--color-primary-pressed);
  box-shadow: 0 0 0 6px var(--glow-primary);
}
.btn-primary:active { background: var(--color-primary-pressed); }

.btn-outline {
  background: transparent;
  border-color: var(--color-border);
  color: var(--color-text);
}
.btn-outline:hover { border-color: var(--color-primary); color: var(--color-primary); }

.btn-sm { min-height: 44px; padding: .4rem 1rem; font-size: .85rem; }

/* ---------- 首屏 Hero + 工具 ---------- */

.hero {
  min-height: calc(100vh - var(--header-height));
  display: flex;
  align-items: center;
  padding: 3rem 0;
  position: relative;
  overflow: hidden;
}

/* 品牌蓝径向光晕 */
.hero::before {
  content: '';
  position: absolute;
  top: -22%;
  left: 50%;
  transform: translateX(-50%);
  width: 920px;
  height: 620px;
  background: radial-gradient(ellipse at center, rgba(15, 112, 230, .14), transparent 65%);
  pointer-events: none;
}

/* 细点阵纹理（仅顶部，渐隐） */
.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle, var(--color-border) 1px, transparent 1.5px);
  background-size: 26px 26px;
  opacity: .5;
  -webkit-mask-image: radial-gradient(ellipse 70% 55% at 50% 0%, #000 25%, transparent 75%);
  mask-image: radial-gradient(ellipse 70% 55% at 50% 0%, #000 25%, transparent 75%);
  pointer-events: none;
}

.hero-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  pointer-events: none;
}
.hero-blob-a {
  width: 420px;
  height: 420px;
  top: -120px;
  left: -100px;
  background: radial-gradient(circle, rgba(15, 112, 230, .22), transparent 70%);
}
.hero-blob-b {
  width: 360px;
  height: 360px;
  bottom: -80px;
  right: -80px;
  background: radial-gradient(circle, rgba(147, 227, 192, .35), transparent 70%);
}

/* 若隐若现的二进制水印（纯装饰） */
.hero-watermark {
  position: absolute;
  inset: -10% -5%;
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  letter-spacing: .35em;
  white-space: nowrap;
  color: var(--color-primary);
  opacity: .05;
  font-size: clamp(1rem, 2.6vw, 1.5rem);
  user-select: none;
  pointer-events: none;
  transform: rotate(-4deg);
}

.hero-inner {
  width: 100%;
  text-align: center;
  position: relative;
  z-index: 1;
}

.hero h1 { margin-bottom: .75rem; }

/* H1 渐变文字（不支持 background-clip 时退回纯色） */
@supports ((-webkit-background-clip: text) or (background-clip: text)) {
  .hero h1 {
    background: linear-gradient(120deg, var(--color-text) 30%, var(--color-primary) 80%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
  }
}

.hero-sub {
  font-size: 1.15rem;
  color: var(--color-text-secondary);
  max-width: 36rem;
  margin: 0 auto 1rem;
}

.trust-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: .5rem 1.5rem;
  padding: 0;
  margin: 0 0 2rem;
  color: var(--color-text-secondary);
  font-size: .9rem;
}
.trust-list li {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
}
.trust-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: rgba(15, 112, 230, .1);
  color: var(--color-primary);
  flex: none;
}
.trust-icon svg { width: 13px; height: 13px; }

/* 工具卡片：首屏视觉焦点（渐变边框 + 更深阴影） */
.tool-card {
  background:
    linear-gradient(var(--color-bg), var(--color-bg)) padding-box,
    linear-gradient(140deg, rgba(15, 112, 230, .55), rgba(15, 112, 230, .08) 45%, rgba(147, 227, 192, .4)) border-box;
  border: 1px solid transparent;
  border-radius: var(--radius-card);
  box-shadow: 0 12px 40px -4px rgba(0, 27, 45, .16);
  padding: 2rem;
  text-align: left;
  position: relative;
}

.tool-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1rem;
  align-items: stretch;
  margin-top: 1.25rem;
}

.swap-col { display: flex; align-items: center; }

.field-label {
  display: block;
  font-weight: 700;
  font-size: .9rem;
  margin-bottom: .4rem;
}

textarea,
.output-box {
  width: 100%;
  min-height: 160px;
  padding: .85rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-input-bg);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: .925rem;
  line-height: 1.6;
  resize: vertical;
  word-break: break-all;
  overflow-wrap: anywhere;
  transition: border-color .15s ease-in-out, box-shadow .15s ease-in-out;
}

textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(15, 112, 230, .25);
}

.output-box { margin: 0; white-space: pre-wrap; }
.output-box:empty::before {
  content: attr(data-placeholder);
  color: var(--color-text-secondary);
  opacity: .7;
}

/* 方向 segmented 控件（滑块式选中态） */
.segmented {
  display: inline-flex;
  gap: .25rem;
  padding: .25rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-bg-subtle);
  position: relative;
}

.segmented button {
  border: none;
  background: transparent;
  color: var(--color-text-secondary);
  font-weight: 700;
  font-size: .85rem;
  padding: .45rem 1rem;
  min-height: 44px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  position: relative;
  z-index: 1;
  transition: color .2s ease-in-out;
}

.segmented button[aria-pressed="true"] { color: #FFFFFF; }

.segmented-indicator {
  position: absolute;
  top: .25rem;
  bottom: .25rem;
  left: 0;
  width: 0;
  border-radius: var(--radius-pill);
  background: var(--color-primary);
  box-shadow: 0 2px 8px -1px rgba(15, 112, 230, .5);
  transition: transform .25s var(--ease-out), width .25s var(--ease-out);
}

/* 工具操作行 */
.tool-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin-top: 1rem;
}

/* 状态行 */
.status-line {
  margin-top: 1rem;
  padding: .6rem 1rem;
  border-radius: var(--radius-card);
  font-size: .9rem;
  background: var(--color-bg-subtle);
  color: var(--color-text-secondary);
  min-height: 44px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .5rem;
  border: 1px solid transparent;
  transition: background .2s ease-in-out, color .2s ease-in-out, border-color .2s ease-in-out;
}
.status-line.is-ok {
  background: var(--color-success-bg);
  color: var(--color-success);
  border-color: rgba(30, 127, 79, .3);
}
.status-line.is-error { background: var(--color-error-bg); color: var(--color-error); }

/* 清理报告 */
.clean-report {
  margin-top: .5rem;
  font-size: .85rem;
  color: var(--color-text-secondary);
}
.clean-report button {
  background: none;
  border: none;
  padding: 0;
  color: var(--color-primary);
  font-weight: 700;
  cursor: pointer;
  font-size: inherit;
}
.normalized-preview {
  margin-top: .5rem;
  padding: .6rem .85rem;
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-card);
  font-family: var(--font-mono);
  font-size: .85rem;
  word-break: break-all;
  overflow-wrap: anywhere;
}

/* Error Clinic */
.error-clinic {
  margin-top: 1rem;
  padding: 1rem 1.25rem;
  border: 1px solid var(--color-error);
  border-radius: var(--radius-card);
  background: var(--color-error-bg);
}
.error-clinic h3 { color: var(--color-error); font-size: 1rem; margin-bottom: .25rem; }
.error-clinic p { margin-bottom: .75rem; }
.error-clinic .clinic-actions { display: flex; flex-wrap: wrap; gap: .5rem; }

.ambiguous-box {
  margin-top: 1rem;
  padding: 1rem 1.25rem;
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-card);
  background: var(--color-bg-subtle);
}

/* Advanced settings */
.advanced-settings { margin-top: 1.25rem; }
.advanced-settings summary {
  cursor: pointer;
  font-weight: 700;
  color: var(--color-primary);
  min-height: 44px;
  display: flex;
  align-items: center;
  gap: .5rem;
  padding: .55rem .9rem;
  border: 1px solid rgba(15, 112, 230, .35);
  border-radius: var(--radius-card);
  background: var(--color-bg-subtle);
  list-style: none;
  transition: background .15s ease-in-out, border-color .15s ease-in-out, box-shadow .15s ease-in-out;
}
.advanced-settings summary::-webkit-details-marker { display: none; }
.advanced-settings summary:hover {
  background: rgba(15, 112, 230, .08);
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px rgba(15, 112, 230, .08);
}
.advanced-settings[open] summary {
  border-color: var(--color-primary);
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
}
.advanced-settings .adv-gear { flex: none; }
.advanced-settings .adv-chevron {
  flex: none;
  margin-left: auto;
  color: var(--color-text-secondary);
  transition: transform .2s ease-in-out;
}
.advanced-settings[open] .adv-chevron { transform: rotate(180deg); }
.advanced-settings label { font-size: .9rem; font-weight: 600; margin-right: .5rem; }
.advanced-settings[open] label { display: inline-block; margin: .9rem .5rem .9rem .9rem; }
.advanced-settings[open] select { margin-bottom: .9rem; }
.advanced-settings select {
  min-height: 44px;
  padding: .4rem .75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-input-bg);
  color: var(--color-text);
  font-size: .9rem;
}

/* ---------- 通用卡片 ---------- */

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  box-shadow: var(--color-card-shadow);
  padding: 2rem;
  transition: transform .3s var(--ease-out), box-shadow .3s var(--ease-out), border-color .3s ease-in-out;
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--color-card-shadow-hover);
  border-color: rgba(15, 112, 230, .35);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

/* ---------- 示例 ---------- */

.example-chips {
  display: flex;
  flex-wrap: wrap;
  gap: .6rem;
  margin-top: 1.25rem;
}
.example-chip:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px -4px rgba(0, 27, 45, .15);
}

/* ---------- Explain This Result ---------- */

.explain-panel table,
.inspector-detail table {
  width: 100%;
  border-collapse: collapse;
  font-size: .9rem;
}
.explain-panel td, .explain-panel th,
.inspector-detail td, .inspector-detail th {
  text-align: left;
  padding: .4rem .6rem;
  border-bottom: 1px solid var(--color-border);
}
.explain-panel th, .inspector-detail th {
  font-family: var(--font-body);
  color: var(--color-text-secondary);
  font-weight: 600;
  white-space: nowrap;
}

details.collapsible {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-bg);
  padding: 0;
  margin-top: 1rem;
  transition: border-color .2s ease-in-out, box-shadow .2s ease-in-out;
}
details.collapsible[open] {
  border-color: rgba(15, 112, 230, .35);
  box-shadow: var(--color-card-shadow);
}
details.collapsible summary {
  cursor: pointer;
  font-weight: 700;
  padding: 1rem 1.25rem;
  min-height: 44px;
  display: flex;
  align-items: center;
  list-style-position: inside;
  transition: color .15s ease-in-out;
}
details.collapsible summary:hover { color: var(--color-primary); }
details.collapsible .collapsible-body { padding: 0 1.25rem 1.25rem; }
details.collapsible[open] .collapsible-body { animation: fade-slide-in .3s var(--ease-out); }

/* ---------- Binary Inspector ---------- */

.inspector-chars {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
  margin: 1rem 0;
}
.inspector-chars button {
  min-width: 44px;
  min-height: 44px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-bg-subtle);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 1rem;
  cursor: pointer;
  transition: border-color .15s ease-in-out, color .15s ease-in-out, transform .15s var(--ease-out);
}
.inspector-chars button:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-2px);
}
.inspector-chars button[aria-pressed="true"] { border-color: var(--color-primary); color: var(--color-primary); }

.inspector-detail {
  border-top: 1px solid var(--color-border);
  padding-top: 1rem;
  font-size: .95rem;
}
.inspector-detail .binary-readout {
  font-family: var(--font-mono);
  word-break: break-all;
  overflow-wrap: anywhere;
  background: var(--color-bg-subtle);
  padding: .6rem .85rem;
  border-radius: var(--radius-card);
}

/* ---------- Binary Alphabet ---------- */

.alphabet-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(48px, 1fr));
  gap: .5rem;
  margin: 1.25rem 0;
}
.alphabet-grid button {
  min-height: 48px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
  transition: all .15s var(--ease-out);
}
.alphabet-grid button:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: 0 6px 14px -4px rgba(0, 27, 45, .15);
}
.alphabet-grid button[aria-pressed="true"] {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #FFFFFF;
  box-shadow: 0 0 0 4px var(--glow-primary);
}

.alphabet-detail { font-size: 1rem; }
.alphabet-detail dl {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: .35rem 1.25rem;
  margin: 0;
}
.alphabet-detail dt { color: var(--color-text-secondary); font-weight: 600; }
.alphabet-detail dd { margin: 0; font-family: var(--font-mono); word-break: break-all; }

/* ---------- How it works ---------- */

.steps { list-style: none; counter-reset: step; padding: 0; margin: 1.5rem 0 0; }
.steps li {
  counter-increment: step;
  padding: 1rem 0 1rem 3.25rem;
  position: relative;
  border-bottom: 1px solid var(--color-border);
}
.steps li:last-child { border-bottom: none; }
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 1rem;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #FFFFFF;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 0 5px var(--glow-primary);
}

/* ---------- FAQ ---------- */

.faq-list details {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-bg);
  margin-bottom: .75rem;
  transition: border-color .2s ease-in-out, box-shadow .2s ease-in-out;
}
.faq-list details:hover { border-color: rgba(15, 112, 230, .3); }
.faq-list details[open] {
  border-color: rgba(15, 112, 230, .35);
  box-shadow: var(--color-card-shadow);
}
.faq-list summary {
  cursor: pointer;
  font-weight: 700;
  padding: 1rem 1.25rem;
  min-height: 44px;
  display: flex;
  align-items: center;
  transition: color .15s ease-in-out;
}
.faq-list summary:hover { color: var(--color-primary); }
.faq-list details[open] summary { border-bottom: 1px solid var(--color-border); }
.faq-list .faq-answer { padding: 1rem 1.25rem; color: var(--color-text-secondary); }
.faq-list details[open] .faq-answer { animation: fade-slide-in .25s var(--ease-out); }

@keyframes fade-slide-in {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: none; }
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-bg-subtle);
  padding: 2.5rem 0;
}
.site-footer .container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.footer-links, .social-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  align-items: center;
}
.footer-links a, .social-links a {
  color: var(--color-text-secondary);
  font-weight: 600;
  font-size: .9rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  transition: color .15s ease-in-out;
}
.footer-links a:hover, .social-links a:hover { color: var(--color-primary); }
.footer-note {
  width: 100%;
  margin: .5rem 0 0;
  font-size: .8rem;
  color: var(--color-text-secondary);
}

/* ---------- 回到顶部 / 暗色开关 ---------- */

#scroll-to-top {
  position: fixed;
  right: 16px;
  bottom: 16px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: 18px;
  cursor: pointer;
  display: none;
  z-index: 999;
  box-shadow: var(--color-card-shadow);
  transition: transform .15s var(--ease-out), border-color .15s ease-in-out, color .15s ease-in-out;
}
#scroll-to-top:hover {
  transform: translateY(-2px);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

#theme-toggle {
  min-width: 44px;
  min-height: 44px;
  border-radius: 50%;
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text);
  font-size: 1.1rem;
  cursor: pointer;
  transition: border-color .15s ease-in-out, transform .15s var(--ease-out);
}
#theme-toggle:hover { border-color: var(--color-primary); transform: rotate(12deg); }

/* ---------- Toast 复制反馈 ---------- */

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translateX(-50%) translateY(20px);
  background: var(--color-text);
  color: var(--color-bg);
  padding: .6rem 1.25rem;
  border-radius: var(--radius-pill);
  font-size: .9rem;
  font-weight: 700;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s ease-in-out, transform .2s ease-in-out;
  z-index: 1000;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ---------- 暗色模式装饰微调 ---------- */

[data-theme="dark"] .hero::before {
  background: radial-gradient(ellipse at center, rgba(76, 154, 255, .13), transparent 65%);
}
[data-theme="dark"] .hero::after { opacity: .35; }
[data-theme="dark"] .hero-watermark { opacity: .07; }
[data-theme="dark"] .hero-blob-a {
  background: radial-gradient(circle, rgba(76, 154, 255, .18), transparent 70%);
}
[data-theme="dark"] .hero-blob-b {
  background: radial-gradient(circle, rgba(122, 220, 178, .12), transparent 70%);
}
[data-theme="dark"] .tool-card {
  box-shadow: 0 12px 40px -4px rgba(0, 0, 0, .6);
}
[data-theme="dark"] .segmented-indicator { box-shadow: 0 2px 8px -1px rgba(76, 154, 255, .4); }
[data-theme="dark"] .trust-icon { background: rgba(76, 154, 255, .15); }

/* ---------- 响应式 ---------- */

@media (max-width: 768px) {
  h1 { font-size: 1.9rem; }
  h2 { font-size: 1.4rem; }
  .hero { padding: 2rem 0; }
  .hero-watermark { font-size: .9rem; }
  .hero-blob-a { width: 280px; height: 280px; }
  .hero-blob-b { width: 220px; height: 220px; }
  .tool-card { padding: 1.25rem; }
  .tool-grid { grid-template-columns: 1fr; }
  .swap-col { justify-content: center; }
  .section { padding: 2.5rem 0; }
  .segmented { width: 100%; }
  .segmented button { flex: 1; padding: .45rem .5rem; }
  .wave-divider svg { height: 36px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; animation: none !important; }
  .js .section .container { opacity: 1; transform: none; }
}

/* ==========================================================================
   内页通用（面包屑 / 页头 / 内链模块 / 表单 / 文章 / 博客）
   ========================================================================== */

/* ---------- 面包屑 ---------- */

.breadcrumb {
  font-size: .85rem;
  color: var(--color-text-secondary);
  margin-bottom: 1rem;
}
.breadcrumb ol {
  list-style: none;
  display: inline-flex;
  flex-wrap: wrap;
  gap: .35rem;
  padding: 0;
  margin: 0;
}
.breadcrumb li { display: inline-flex; align-items: center; gap: .35rem; }
.breadcrumb li + li::before { content: '›'; color: var(--color-border); }
.breadcrumb a { color: var(--color-text-secondary); }
.breadcrumb [aria-current] { color: var(--color-text); font-weight: 600; }

/* ---------- 内页页头 ---------- */

.page-hero {
  padding: 3rem 0 2.5rem;
  text-align: center;
  background: radial-gradient(ellipse 60% 100% at 50% 0%, rgba(15, 112, 230, .08), transparent);
}
.page-hero h1 { margin-bottom: .75rem; }
.page-hero .section-lead { margin: 0 auto; }

.logo-link {
  display: flex;
  align-items: center;
  gap: .5rem;
  color: var(--color-text);
}
.logo-link:hover { text-decoration: none; }

/* 内页工具紧跟页头 */
.tool-block { padding-bottom: 3.5rem; }

/* ---------- Related tools / 内链卡片 ---------- */

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}
.related-card {
  display: block;
  color: var(--color-text);
}
.related-card:hover { text-decoration: none; }
.related-card h2, .related-card h3 { font-size: 1rem; margin-bottom: .25rem; color: var(--color-text); }
.related-card p {
  font-size: .85rem;
  color: var(--color-text-secondary);
  margin: 0;
}
.related-card:hover h2, .related-card:hover h3 { color: var(--color-primary); }

/* ---------- 联系表单 ---------- */

.contact-form { max-width: 560px; margin-top: 1.5rem; text-align: left; }
.contact-form label {
  display: block;
  font-weight: 700;
  font-size: .9rem;
  margin: 1rem 0 .3rem;
}
.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: .7rem .9rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-input-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: .95rem;
  transition: border-color .15s ease-in-out, box-shadow .15s ease-in-out;
}
.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(15, 112, 230, .25);
}
.contact-form button { margin-top: 1.25rem; }

/* ---------- 文章页 / 静态内容页 ---------- */

.article-body { max-width: 46rem; margin: 0 auto; text-align: left; }
.article-body h2 { margin-top: 2.5rem; }
.article-body h3 { margin-top: 1.75rem; }
.article-body ul, .article-body ol { padding-left: 1.4rem; color: var(--color-text-secondary); }
.article-body li { margin-bottom: .4rem; }
.article-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: .9rem;
  margin: 1rem 0;
}
.article-body td, .article-body th {
  text-align: left;
  padding: .4rem .6rem;
  border-bottom: 1px solid var(--color-border);
}
.article-body th { color: var(--color-text-secondary); font-weight: 600; }
.article-meta {
  color: var(--color-text-secondary);
  font-size: .85rem;
  margin-bottom: 2rem;
}
.byline {
  color: var(--color-text-secondary);
  font-size: .85rem;
  margin: -.25rem 0 1.5rem;
}
.byline a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ---------- 博客索引 ---------- */

.post-list { display: grid; gap: 1rem; margin-top: 1.5rem; }

/* ---------- 字母表搜索 ---------- */

.alphabet-search-wrap { max-width: 420px; margin: 0 auto; }
#alphabet-search,
#ref-table-search {
  width: 100%;
  min-height: 48px;
  padding: .6rem 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-input-bg);
  color: var(--color-text);
  font-size: 1rem;
  font-family: var(--font-body);
  transition: border-color .15s ease-in-out, box-shadow .15s ease-in-out;
}
#alphabet-search:focus,
#ref-table-search:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(15, 112, 230, .25);
}

/* ---------- 首页完整对照表 ---------- */

.ref-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .9rem;
  margin: 1rem 0;
}
.ref-table td, .ref-table th {
  text-align: left;
  padding: .4rem .6rem;
  border-bottom: 1px solid var(--color-border);
}
.ref-table thead th { color: var(--color-text-secondary); font-weight: 600; }

/* ---------- Header 右侧动作组 + 移动端汉堡菜单（≤900px） ---------- */

.header-actions { display: flex; align-items: center; gap: .5rem; }

.logo-link span { white-space: nowrap; }

#theme-toggle {
  flex: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-border);
  border-radius: 99px;
  background: var(--color-bg);
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  transition: border-color .15s ease-in-out, box-shadow .15s ease-in-out;
}
#theme-toggle:hover { border-color: var(--color-primary); box-shadow: 0 0 0 4px rgba(15, 112, 230, .12); }

#menu-toggle {
  display: none;
  flex: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-border);
  border-radius: 99px;
  background: var(--color-bg);
  color: var(--color-text);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  transition: border-color .15s ease-in-out, box-shadow .15s ease-in-out;
}
#menu-toggle:hover { border-color: var(--color-primary); box-shadow: 0 0 0 4px rgba(15, 112, 230, .12); }

/* 面板默认不渲染；[hidden] 需显式压过媒体查询里的 display:block */
.mobile-menu { display: none; }

@media (max-width: 900px) {
  .nav-links { display: none; }
  #menu-toggle { display: inline-flex; }
  .mobile-menu {
    display: block;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    padding: .5rem 1rem .75rem;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 16px 32px -12px rgba(0, 27, 45, .22);
    opacity: 0;
    transform: translateY(-6px);
    transition: opacity .2s var(--ease-out), transform .2s var(--ease-out);
  }
  .mobile-menu[hidden] { display: none; }
  .mobile-menu.is-open { opacity: 1; transform: none; }
  .mobile-menu a {
    display: flex;
    align-items: center;
    min-height: 48px;
    padding: .5rem .75rem;
    border-radius: var(--radius-card);
    color: var(--color-text);
    font-weight: 600;
  }
  .mobile-menu a:hover { color: var(--color-primary); background: var(--color-bg-subtle); text-decoration: none; }
}

[data-theme="dark"] .mobile-menu { box-shadow: 0 16px 32px -12px rgba(0, 0, 0, .6); }

@media (max-width: 600px) {
  .site-header .container { gap: .5rem; }
  .logo { font-size: .92rem; gap: .4rem; }
  .logo svg { width: 24px; height: 24px; }
}

@media (max-width: 480px) {
  .logo-link span { display: none; } /* 极小屏只留图标，导航走汉堡菜单 */
  .segmented button { font-size: .78rem; padding: .45rem .3rem; } /* 三段方向控件单行放下 */
}

/* ---------- 移动端防溢出 ---------- */

pre.mono { white-space: pre-wrap; word-break: break-all; overflow-wrap: anywhere; }
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }