/* ═══════════════════════════════════════════════════════════════════
   EZCAI Calculators — 计算器矩阵设计系统
   零构建 · 零 CDN · 零外部依赖 · 纯手写 CSS
   设计语言来源：MotionSites.ai «Price Calculator» (SaaS)
                动效关键词 slide / fade / counter
                Motion Site Builder profile: product-ui（交互）
                                            cinematic（Hero 入场）
   配色：与 DataAlgorithm 青蓝冷调同源，识别色改为琥珀-绿松石「工具」调
   ═══════════════════════════════════════════════════════════════════ */

:root {
  /* ── 底色：与 algo.css 完全同源，保证跨栏目视觉连续 ───────────── */
  --calc-bg:          #07070C;
  --calc-bg-alt:      #0D0D14;
  --calc-surface:     rgba(19, 21, 32, 0.72);
  --calc-surface-sol: #13151F;
  --calc-fg:          #F2F4F8;
  --calc-muted:       #9AA3B5;   /* 次级正文：对深底 ≥ 7.0:1 */
  --calc-dim:         #7E879B;   /* 弱化小字：11–13px 仍需 ≥ 4.5:1 → 不可再暗 */

  /* ── 模块识别色：工具暖调（区别于 DataAlgorithm 的纯青蓝） ─────── */
  --calc-amber:       #FBBF24;
  --calc-amber-dim:   #B45309;
  --calc-teal:        #2DD4BF;
  --calc-teal-dim:    #0F766E;
  --calc-cyan:        #22D3EE;   /* 跨栏目锚点色，指向 DataAlgorithm */
  --calc-violet:      #A78BFA;
  --calc-mint:        #34D399;

  --calc-border:      rgba(255, 255, 255, 0.075);
  --calc-border-hi:   rgba(251, 191, 36, 0.30);
  --calc-border-teal: rgba(45, 212, 191, 0.28);
  --calc-grid:        rgba(255, 255, 255, 0.045);

  --calc-radius-sm:   6px;
  --calc-radius:      12px;
  --calc-radius-lg:   18px;
  --calc-radius-pill: 999px;

  --calc-shadow:      0 18px 48px rgba(0, 0, 0, 0.42);
  --calc-shadow-lift: 0 24px 64px rgba(0, 0, 0, 0.52);
  --calc-glow-amber:  0 0 0 1px rgba(251, 191, 36, 0.26), 0 0 34px rgba(251, 191, 36, 0.13);
  --calc-glow-teal:   0 0 0 1px rgba(45, 212, 191, 0.26), 0 0 34px rgba(45, 212, 191, 0.13);

  --calc-mono:        ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Consolas, monospace;
  --calc-sans:        Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                      "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --calc-serif:       "Source Serif 4", Georgia, "Songti SC", "Noto Serif CJK SC", serif;

  --calc-shell:       min(1240px, 100%);
  --calc-measure:     min(70ch, 100%);

  /* ── 动效令牌：直取 Motion Site Builder config，不近似 ─────────── */
  /* cinematic（Hero 入场，0.5–1.2s 预算） */
  --calc-ease-expo:   cubic-bezier(0.16, 1, 0.3, 1);
  --calc-ease-quint:  cubic-bezier(0.22, 1, 0.36, 1);
  --calc-ease-pop:    cubic-bezier(0.34, 1.56, 0.64, 1);
  /* product-ui（交互，micro 0.1–0.2s / entrance 0.15–0.35s） */
  --calc-ease-ui:     cubic-bezier(0.23, 1, 0.32, 1);
  --calc-ease-std:    cubic-bezier(0.4, 0, 0.2, 1);

  --calc-dur-micro:   140ms;   /* product-ui micro 上限 200ms 内 */
  --calc-dur-ui:      220ms;   /* product-ui entrance */
  --calc-dur-hero:    800ms;   /* cinematic entrance */
  --calc-stagger:     40ms;    /* product-ui stagger default 0.04s */
}

/* ═══ 基础重置 ═══════════════════════════════════════════════════ */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  background: var(--calc-bg);
  color: var(--calc-fg);
  font-family: var(--calc-sans);
  font-size: 16px;
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }

:focus-visible {
  outline: 2px solid var(--calc-amber);
  outline-offset: 3px;
  border-radius: 3px;
}

.calc-shell {
  width: var(--calc-shell);
  margin-inline: auto;
  padding-inline: clamp(18px, 4vw, 40px);
}

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

/* ═══ 签名原语（verbatim from component-catalog.md，值不改） ══════ */

/* 1. liquid-glass */
.liquid-glass {
  background: rgba(255, 255, 255, 0.01);
  background-blend-mode: luminosity;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  border: none;
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.1);
  position: relative;
  overflow: hidden;
}
.liquid-glass::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1.4px;
  background: linear-gradient(180deg,
    rgba(255,255,255,0.45) 0%, rgba(255,255,255,0.15) 20%,
    rgba(255,255,255,0) 40%, rgba(255,255,255,0) 60%,
    rgba(255,255,255,0.15) 80%, rgba(255,255,255,0.45) 100%);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

/* 3. entrance-keyframes */
@keyframes fade-up {
  from { opacity: 0; transform: translateY(24px); filter: blur(6px); }
  to   { opacity: 1; transform: translateY(0);   filter: blur(0); }
}
.animate-fade-up {
  animation: fade-up 0.8s cubic-bezier(0.16, 1, 0.3, 1) backwards;
}
.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.25s; }
.delay-3 { animation-delay: 0.4s; }

/* 17. product-ui-stat-card 的 ui-rise（交互层入场） */
@keyframes ui-rise {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: none; }
}

/* 11. reduced-motion-boilerplate —— 强制项，M01 规则 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ═══ 顶栏：glass-nav-pill 变体 ═════════════════════════════════ */

.calc-topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7, 7, 12, 0.82);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid var(--calc-border);
}

.calc-topbar__inner {
  width: var(--calc-shell);
  margin-inline: auto;
  padding: 12px clamp(18px, 4vw, 40px);
  display: flex;
  align-items: center;
  gap: 22px;
}

.calc-brand { display: flex; align-items: center; gap: 11px; flex-shrink: 0; }

.calc-brand__mark {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border-radius: var(--calc-radius-sm);
  background: linear-gradient(140deg, var(--calc-amber) 0%, var(--calc-amber-dim) 100%);
  color: #0B0B10;
  font-family: var(--calc-mono);
  font-size: 13px; font-weight: 700; letter-spacing: -0.02em;
  box-shadow: 0 0 22px rgba(251, 191, 36, 0.22);
}

.calc-brand__text { display: flex; flex-direction: column; line-height: 1.2; }
.calc-brand__name { font-size: 14.5px; font-weight: 650; letter-spacing: -0.01em; }
.calc-brand__sub {
  font-family: var(--calc-mono);
  font-size: 10.5px; color: var(--calc-dim);
  letter-spacing: 0.06em; text-transform: uppercase;
}

.calc-nav {
  display: flex; align-items: center; gap: 4px;
  margin-left: auto; flex-wrap: wrap;
}

.calc-nav__link {
  padding: 7px 13px;
  border-radius: var(--calc-radius-pill);
  font-size: 13.5px;
  color: var(--calc-muted);
  border: 1px solid transparent;
  transition: color var(--calc-dur-micro) var(--calc-ease-ui),
              background-color var(--calc-dur-micro) var(--calc-ease-ui),
              border-color var(--calc-dur-micro) var(--calc-ease-ui);
}
@media (hover: hover) and (pointer: fine) {
  .calc-nav__link:hover {
    color: var(--calc-fg);
    background: rgba(255, 255, 255, 0.05);
  }
}
.calc-nav__link:active { transform: scale(0.97); }
.calc-nav__link[aria-current="page"] {
  color: var(--calc-amber);
  border-color: var(--calc-border-hi);
  background: rgba(251, 191, 36, 0.07);
}

.calc-nav__home {
  padding: 7px 14px;
  border-radius: var(--calc-radius-pill);
  border: 1px solid var(--calc-border);
  font-size: 13px; color: var(--calc-muted);
  font-family: var(--calc-mono);
  transition: border-color var(--calc-dur-micro) var(--calc-ease-ui),
              color var(--calc-dur-micro) var(--calc-ease-ui);
}
@media (hover: hover) and (pointer: fine) {
  .calc-nav__home:hover { border-color: var(--calc-border-teal); color: var(--calc-teal); }
}

/* ═══ Hero：cinematic 入场 ══════════════════════════════════════ */

.calc-hero {
  position: relative;
  padding: clamp(64px, 11vw, 132px) 0 clamp(48px, 7vw, 84px);
  overflow: hidden;
  isolation: isolate;
}

/* 环境层 z-index 0：网格 + 双光斑，纯 CSS，无图片无视频 */
.calc-hero__grid {
  position: absolute; inset: 0; z-index: 0;
  background-image:
    linear-gradient(to right, var(--calc-grid) 1px, transparent 1px),
    linear-gradient(to bottom, var(--calc-grid) 1px, transparent 1px);
  background-size: 62px 62px;
  mask-image: radial-gradient(ellipse 72% 58% at 50% 32%, #000 22%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 72% 58% at 50% 32%, #000 22%, transparent 78%);
  pointer-events: none;
}

.calc-hero__aura {
  position: absolute; z-index: 0;
  border-radius: 50%;
  filter: blur(88px);
  pointer-events: none;
  opacity: 0.5;
}
.calc-hero__aura--a {
  width: 46vw; height: 34vw;
  top: -12%; left: 4%;
  background: radial-gradient(circle, rgba(251, 191, 36, 0.20) 0%, transparent 66%);
  animation: aura-drift-a 22s var(--calc-ease-std) infinite alternate;
}
.calc-hero__aura--b {
  width: 40vw; height: 30vw;
  top: 6%; right: 2%;
  background: radial-gradient(circle, rgba(45, 212, 191, 0.18) 0%, transparent 66%);
  animation: aura-drift-b 27s var(--calc-ease-std) infinite alternate;
}
@keyframes aura-drift-a {
  from { transform: translate3d(0, 0, 0) scale(1); }
  to   { transform: translate3d(4%, 5%, 0) scale(1.1); }
}
@keyframes aura-drift-b {
  from { transform: translate3d(0, 0, 0) scale(1.06); }
  to   { transform: translate3d(-5%, 4%, 0) scale(1); }
}

/* 内容层 z-index 1 */
.calc-hero__inner { position: relative; z-index: 1; }

.calc-eyebrow {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 6px 15px 6px 11px;
  border-radius: var(--calc-radius-pill);
  border: 1px solid var(--calc-border-hi);
  background: rgba(251, 191, 36, 0.06);
  font-family: var(--calc-mono);
  font-size: 11.5px; letter-spacing: 0.09em; text-transform: uppercase;
  color: var(--calc-amber);
}
.calc-eyebrow__dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--calc-amber);
  box-shadow: 0 0 10px var(--calc-amber);
  animation: dot-pulse 2.6s var(--calc-ease-std) infinite;
}
@keyframes dot-pulse {
  0%, 100% { opacity: 1;   transform: scale(1); }
  50%      { opacity: 0.45; transform: scale(0.8); }
}

.calc-hero__title {
  margin: 24px 0 0;
  font-size: clamp(2.35rem, 6.2vw, 4.3rem);
  line-height: 1.08;
  font-weight: 700;
  letter-spacing: -0.032em;
  max-width: 19ch;
}
.calc-hero__title em {
  font-style: normal;
  background: linear-gradient(100deg, var(--calc-amber) 0%, var(--calc-teal) 92%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.calc-hero__lede {
  margin: 22px 0 0;
  max-width: var(--calc-measure);
  font-size: clamp(1rem, 1.6vw, 1.14rem);
  color: var(--calc-muted);
  line-height: 1.76;
}
.calc-hero__lede strong { color: var(--calc-fg); font-weight: 600; }

.calc-hero__cta { margin: 34px 0 0; display: flex; flex-wrap: wrap; gap: 12px; }

/* ═══ 按钮：13. press-scale-button（值 verbatim） ═══════════════ */

.calc-btn {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 12px 24px;
  border-radius: var(--calc-radius-pill);
  border: 1px solid transparent;
  font-family: inherit;
  font-size: 14.5px; font-weight: 600;
  cursor: pointer;
  transition: transform 160ms cubic-bezier(0.16, 1, 0.3, 1),
              box-shadow var(--calc-dur-micro) var(--calc-ease-ui),
              border-color var(--calc-dur-micro) var(--calc-ease-ui),
              background-color var(--calc-dur-micro) var(--calc-ease-ui),
              color var(--calc-dur-micro) var(--calc-ease-ui);
}
.calc-btn:active { transform: scale(0.97); }

.calc-btn--primary {
  background: linear-gradient(135deg, var(--calc-amber) 0%, #F59E0B 100%);
  color: #0B0B10;
  box-shadow: 0 8px 26px rgba(251, 191, 36, 0.20);
}
@media (hover: hover) and (pointer: fine) {
  .calc-btn--primary:hover { box-shadow: 0 12px 36px rgba(251, 191, 36, 0.30); }
}

/* 用户偏好：导航型按钮用深底蓝/青框，不用鲜艳渐变 */
.calc-btn--ghost {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--calc-border);
  color: var(--calc-fg);
}
@media (hover: hover) and (pointer: fine) {
  .calc-btn--ghost:hover { border-color: var(--calc-border-teal); color: var(--calc-teal); }
}

.calc-btn__arrow {
  font-family: var(--calc-mono);
  transition: transform var(--calc-dur-micro) var(--calc-ease-ui);
}
@media (hover: hover) and (pointer: fine) {
  .calc-btn:hover .calc-btn__arrow { transform: translateX(3px); }
}

/* ═══ Hero 统计条：counter 动效关键词的静态落点 ════════════════ */

.calc-stats {
  margin: 52px 0 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(148px, 1fr));
  gap: 1px;
  background: var(--calc-border);
  border: 1px solid var(--calc-border);
  border-radius: var(--calc-radius);
  overflow: hidden;
}

.calc-stat {
  background: var(--calc-bg-alt);
  padding: 20px 22px;
  animation: ui-rise 0.22s var(--calc-ease-ui) backwards;
}
.calc-stat:nth-child(1) { animation-delay: 480ms; }
.calc-stat:nth-child(2) { animation-delay: 520ms; }
.calc-stat:nth-child(3) { animation-delay: 560ms; }
.calc-stat:nth-child(4) { animation-delay: 600ms; }

.calc-stat__num {
  font-family: var(--calc-mono);
  font-size: clamp(1.5rem, 2.6vw, 1.95rem);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.03em;
  color: var(--calc-fg);
  line-height: 1.1;
}
.calc-stat__num em {
  font-style: normal;
  font-size: 0.56em;
  color: var(--calc-teal);
  margin-left: 2px;
}
.calc-stat__label {
  margin-top: 6px;
  font-size: 12.5px;
  color: var(--calc-dim);
  letter-spacing: 0.01em;
}

/* ═══ 区块通用 ═════════════════════════════════════════════════ */

.calc-section { padding: clamp(56px, 8vw, 96px) 0; }
.calc-section--alt {
  background: var(--calc-bg-alt);
  border-block: 1px solid var(--calc-border);
}

.calc-section__head { margin-bottom: 40px; }

.calc-section__kicker {
  font-family: var(--calc-mono);
  font-size: 11.5px; letter-spacing: 0.11em; text-transform: uppercase;
  color: var(--calc-teal);
  display: flex; align-items: center; gap: 10px;
}
.calc-section__kicker::before {
  content: ''; width: 22px; height: 1px;
  background: var(--calc-teal); opacity: 0.6;
}

.calc-section__title {
  margin: 14px 0 0;
  font-size: clamp(1.62rem, 3.4vw, 2.28rem);
  font-weight: 680;
  letter-spacing: -0.025em;
  line-height: 1.2;
}

.calc-section__desc {
  margin: 13px 0 0;
  max-width: var(--calc-measure);
  color: var(--calc-muted);
  font-size: 15.2px;
  line-height: 1.74;
}

/* ═══ 簇分组标题 ═══════════════════════════════════════════════ */

.calc-cluster { margin-top: 52px; }
.calc-cluster:first-of-type { margin-top: 0; }

.calc-cluster__bar {
  display: flex; align-items: baseline; gap: 14px;
  padding-bottom: 13px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--calc-border);
}

.calc-cluster__id {
  font-family: var(--calc-mono);
  font-size: 12px; font-weight: 700;
  letter-spacing: 0.08em;
  padding: 3px 9px;
  border-radius: var(--calc-radius-sm);
}
.calc-cluster--a .calc-cluster__id { color: var(--calc-amber); background: rgba(251,191,36,0.10); }
.calc-cluster--b .calc-cluster__id { color: var(--calc-teal);  background: rgba(45,212,191,0.10); }
.calc-cluster--c .calc-cluster__id { color: var(--calc-violet);background: rgba(167,139,250,0.10); }
.calc-cluster--d .calc-cluster__id { color: var(--calc-mint);  background: rgba(52,211,153,0.10); }

.calc-cluster__name {
  font-size: 17px; font-weight: 640; letter-spacing: -0.015em;
}
.calc-cluster__note {
  margin-left: auto;
  font-size: 12.5px; color: var(--calc-dim);
  font-family: var(--calc-mono);
}

/* ═══ 计算器卡片网格：17. product-ui-stat-card 语汇 ════════════ */

.calc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(272px, 1fr));
  gap: 16px;
}

.calc-card {
  position: relative;
  display: flex; flex-direction: column;
  padding: 22px 22px 20px;
  border-radius: var(--calc-radius);
  border: 1px solid var(--calc-border);
  background: var(--calc-surface-sol);
  overflow: hidden;
  animation: ui-rise 0.22s var(--calc-ease-ui) backwards;
  transition: transform var(--calc-dur-micro) var(--calc-ease-ui),
              box-shadow var(--calc-dur-micro) var(--calc-ease-ui),
              border-color var(--calc-dur-micro) var(--calc-ease-ui);
}
.calc-card:nth-child(1){animation-delay:0ms}   .calc-card:nth-child(2){animation-delay:40ms}
.calc-card:nth-child(3){animation-delay:80ms}  .calc-card:nth-child(4){animation-delay:120ms}
.calc-card:nth-child(5){animation-delay:160ms} .calc-card:nth-child(6){animation-delay:200ms}

/* 顶部识别色细线，hover 时横向铺满 —— slide 动效关键词
   用 transform: scaleX 而非 width：只走合成层，不触发 layout */
.calc-card::after {
  content: '';
  position: absolute; top: 0; left: 0;
  height: 2px; width: 100%;
  transform: scaleX(0.12);
  transform-origin: left center;
  background: var(--calc-dim);
  transition: transform var(--calc-dur-ui) var(--calc-ease-ui),
              background-color var(--calc-dur-ui) var(--calc-ease-ui);
}
.calc-card--a::after { background: var(--calc-amber); }
.calc-card--b::after { background: var(--calc-teal); }
.calc-card--c::after { background: var(--calc-violet); }
.calc-card--d::after { background: var(--calc-mint); }

.calc-card:active { transform: scale(0.985); }

@media (hover: hover) and (pointer: fine) {
  .calc-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--calc-shadow-lift);
    border-color: var(--calc-border-hi);
  }
  .calc-card:hover::after { transform: scaleX(1); }
}

/* ═══ 卡片内部元素 ═════════════════════════════════════════════ */

.calc-card__top {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 13px;
}

.calc-card__id {
  font-family: var(--calc-mono);
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.07em;
  color: var(--calc-dim);
}

.calc-card__badge {
  margin-left: auto;
  font-family: var(--calc-mono);
  font-size: 10px; letter-spacing: 0.07em; text-transform: uppercase;
  padding: 3px 8px;
  border-radius: var(--calc-radius-pill);
  border: 1px solid var(--calc-border);
  color: var(--calc-dim);
}
.calc-card__badge--live {
  color: var(--calc-mint);
  border-color: rgba(52, 211, 153, 0.30);
  background: rgba(52, 211, 153, 0.07);
}
.calc-card__badge--soon {
  color: var(--calc-dim);
}
.calc-card__badge--pro {
  color: var(--calc-amber);
  border-color: var(--calc-border-hi);
  background: rgba(251, 191, 36, 0.07);
}

.calc-card__title {
  margin: 0;
  font-size: 16.5px; font-weight: 640;
  letter-spacing: -0.016em;
  line-height: 1.34;
}

.calc-card__q {
  margin: 9px 0 0;
  font-size: 13.6px;
  color: var(--calc-muted);
  line-height: 1.66;
  flex: 1;
}

.calc-card__meta {
  margin-top: 16px;
  padding-top: 13px;
  border-top: 1px solid var(--calc-border);
  display: flex; align-items: center; gap: 12px;
  font-family: var(--calc-mono);
  font-size: 11.5px;
  color: var(--calc-dim);
}
.calc-card__io { font-variant-numeric: tabular-nums; }
.calc-card__link {
  margin-left: auto;
  color: var(--calc-teal);
  display: inline-flex; align-items: center; gap: 5px;
  transition: gap var(--calc-dur-micro) var(--calc-ease-ui);
}
@media (hover: hover) and (pointer: fine) {
  .calc-card:hover .calc-card__link { gap: 9px; }
}
.calc-card__link--muted { color: var(--calc-dim); }

/* ═══ 六条产品原则 ═════════════════════════════════════════════ */

.calc-principles {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(258px, 1fr));
  gap: 1px;
  background: var(--calc-border);
  border: 1px solid var(--calc-border);
  border-radius: var(--calc-radius);
  overflow: hidden;
}

.calc-principle {
  background: var(--calc-bg);
  padding: 24px 22px;
  transition: background-color var(--calc-dur-ui) var(--calc-ease-ui);
}
@media (hover: hover) and (pointer: fine) {
  .calc-principle:hover { background: var(--calc-surface-sol); }
}

.calc-principle__n {
  font-family: var(--calc-mono);
  font-size: 12px; font-weight: 700;
  color: var(--calc-amber);
  letter-spacing: 0.06em;
}
.calc-principle__t {
  margin: 10px 0 0;
  font-size: 15px; font-weight: 640;
  letter-spacing: -0.014em;
}
.calc-principle__d {
  margin: 8px 0 0;
  font-size: 13.4px;
  color: var(--calc-muted);
  line-height: 1.68;
}

/* ═══ 跨栏目互链条 ═════════════════════════════════════════════ */

.calc-bridge {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 14px;
  margin-top: 8px;
}

.calc-bridge__item {
  position: relative;
  padding: 20px 22px;
  border-radius: var(--calc-radius);
  border: 1px solid var(--calc-border);
  background: var(--calc-surface-sol);
  transition: transform var(--calc-dur-micro) var(--calc-ease-ui),
              border-color var(--calc-dur-micro) var(--calc-ease-ui);
}
.calc-bridge__item:active { transform: scale(0.985); }
@media (hover: hover) and (pointer: fine) {
  .calc-bridge__item:hover {
    transform: translateY(-2px);
    border-color: rgba(34, 211, 238, 0.28);
  }
}
.calc-bridge__tag {
  font-family: var(--calc-mono);
  font-size: 10.5px; letter-spacing: 0.09em; text-transform: uppercase;
  color: var(--calc-cyan);
}
.calc-bridge__t {
  margin: 9px 0 0;
  font-size: 15px; font-weight: 620; letter-spacing: -0.014em;
}
.calc-bridge__d {
  margin: 7px 0 0;
  font-size: 13.2px; color: var(--calc-muted); line-height: 1.64;
}

/* ═══ 页脚 ═════════════════════════════════════════════════════ */

.calc-footer {
  border-top: 1px solid var(--calc-border);
  background: var(--calc-bg-alt);
  padding: clamp(40px, 6vw, 64px) 0 30px;
}

.calc-footer__grid {
  display: grid;
  grid-template-columns: minmax(220px, 1.4fr) repeat(auto-fit, minmax(150px, 1fr));
  gap: 34px;
}

.calc-footer__about {
  margin: 14px 0 0;
  font-size: 13.4px; color: var(--calc-muted);
  line-height: 1.72;
  max-width: 42ch;
}

.calc-footer__h {
  font-family: var(--calc-mono);
  font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--calc-dim);
  margin-bottom: 13px;
}

.calc-footer__list { list-style: none; margin: 0; padding: 0; }
.calc-footer__list li + li { margin-top: 8px; }
.calc-footer__list a {
  font-size: 13.4px; color: var(--calc-muted);
  transition: color var(--calc-dur-micro) var(--calc-ease-ui);
}
@media (hover: hover) and (pointer: fine) {
  .calc-footer__list a:hover { color: var(--calc-teal); }
}

.calc-footer__bar {
  margin-top: 38px; padding-top: 20px;
  border-top: 1px solid var(--calc-border);
  display: flex; flex-wrap: wrap; gap: 12px; align-items: center;
  font-family: var(--calc-mono);
  font-size: 11.5px; color: var(--calc-dim);
}
.calc-footer__bar span + span::before {
  content: '·'; margin-right: 10px; opacity: 0.5;
}

/* ═══ 响应式 ═══════════════════════════════════════════════════ */

@media (max-width: 900px) {
  .calc-topbar__inner { flex-wrap: wrap; gap: 12px; }
  .calc-nav { margin-left: 0; width: 100%; }
  .calc-hero__title { max-width: 100%; }
  .calc-cluster__note { margin-left: 0; width: 100%; margin-top: 6px; }
  .calc-cluster__bar { flex-wrap: wrap; }
}

@media (max-width: 620px) {
  html { scroll-padding-top: 130px; }
  .calc-hero { padding-top: 48px; }
  .calc-stats { grid-template-columns: repeat(2, 1fr); }
  .calc-grid { grid-template-columns: 1fr; }
  .calc-footer__grid { grid-template-columns: 1fr; gap: 26px; }
  .calc-btn { width: 100%; justify-content: center; }
}

/* 打印：去掉动效与装饰 */
@media print {
  .calc-hero__grid, .calc-hero__aura, .calc-topbar { display: none; }
  body { background: #fff; color: #000; }
}