/**
 * [INPUT]: 依赖 index.html 的全局语义结构与 Google Fonts 字体资源
 * [OUTPUT]: 提供设计令牌、基础元素、导航、首屏工具面板与元数据类型网格
 * [POS]: css 模块的基础视觉层，被 sections.css 与 responsive.css 共同扩展
 * [PROTOCOL]: 变更时更新此头部，然后检查 AGENTS.md
 */

:root {
  --paper: #f1eee5;
  --paper-deep: #e5e0d3;
  --paper-bright: #faf8f2;
  --ink: #161914;
  --ink-soft: #353a31;
  --muted: #6f746a;
  --line: rgba(22, 25, 20, 0.18);
  --line-strong: rgba(22, 25, 20, 0.42);
  --signal: #b9ff66;
  --signal-deep: #8adf36;
  --warning: #ff6b4a;
  --amber: #f4b84a;
  --white: #fff;
  --display: "Newsreader", Georgia, serif;
  --sans: "Manrope", sans-serif;
  --mono: "IBM Plex Mono", monospace;
  --shell: min(1180px, calc(100vw - 48px));
  --shadow-hard: 10px 10px 0 rgba(22, 25, 20, 0.13);
  --transition: 180ms ease;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body.menu-open {
  overflow: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input {
  font: inherit;
}

button,
a,
label {
  -webkit-tap-highlight-color: transparent;
}

svg {
  display: block;
  width: 24px;
  height: 24px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: square;
  stroke-linejoin: miter;
}

.svg-defs {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
}

.shell {
  width: var(--shell);
  margin-inline: auto;
}

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

.skip-link {
  position: fixed;
  z-index: 1000;
  top: 12px;
  left: 12px;
  padding: 10px 16px;
  background: var(--signal);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 12px;
  transform: translateY(-150%);
  transition: transform var(--transition);
}

.skip-link:focus {
  transform: translateY(0);
}

:focus-visible {
  outline: 3px solid var(--signal-deep);
  outline-offset: 4px;
}

.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgba(241, 238, 229, 0.92);
  backdrop-filter: blur(14px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 72px;
}

.brand {
  display: inline-flex;
  gap: 12px;
  align-items: center;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand-mark {
  position: relative;
  display: grid;
  width: 25px;
  height: 25px;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr 1fr;
}

.brand-mark span {
  width: 8px;
  height: 8px;
  border-color: currentColor;
  border-style: solid;
}

.brand-mark span:nth-child(1) {
  align-self: start;
  justify-self: start;
  border-width: 2px 0 0 2px;
}

.brand-mark span:nth-child(2) {
  align-self: start;
  justify-self: end;
  border-width: 2px 2px 0 0;
}

.brand-mark span:nth-child(3) {
  align-self: end;
  justify-self: start;
  border-width: 0 0 2px 2px;
}

.brand-mark span:nth-child(4) {
  align-self: end;
  justify-self: end;
  border-width: 0 2px 2px 0;
}

.site-nav {
  display: flex;
  gap: 32px;
  align-items: center;
  font-size: 13px;
  font-weight: 600;
}

.site-nav > a:not(.nav-cta) {
  position: relative;
}

.site-nav > a:not(.nav-cta)::after {
  position: absolute;
  right: 0;
  bottom: -6px;
  left: 0;
  height: 1px;
  background: currentColor;
  content: "";
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--transition);
}

.site-nav > a:not(.nav-cta):hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.nav-cta {
  padding: 10px 16px;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--paper-bright);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition:
    background var(--transition),
    color var(--transition);
}

.nav-cta:hover {
  background: var(--signal);
  color: var(--ink);
}

.menu-toggle {
  display: none;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 94px 0 0;
  border-bottom: 1px solid var(--line);
}

.hero-grid,
.cta-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(22, 25, 20, 0.06) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(22, 25, 20, 0.06) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  mask-image: linear-gradient(to bottom, black 0%, transparent 82%);
}

.hero-layout {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.03fr) minmax(420px, 0.78fr);
  gap: clamp(56px, 8vw, 120px);
  align-items: center;
  padding-bottom: 82px;
}

.eyebrow,
.section-number,
.panel-bar,
.panel-kicker,
.panel-footer,
.evidence-item small,
.diagram-top,
.report-bar,
.final-cta > div > p {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.eyebrow {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 28px;
}

.status-dot {
  width: 8px;
  height: 8px;
  background: var(--signal-deep);
  box-shadow: 0 0 0 4px rgba(138, 223, 54, 0.14);
}

.hero h1 {
  max-width: 700px;
  margin: 0;
  font-size: clamp(65px, 8.4vw, 126px);
  font-weight: 600;
  letter-spacing: -0.075em;
  line-height: 0.82;
}

.hero h1 span {
  display: block;
  margin-left: 0.7em;
  color: var(--ink-soft);
  font-family: var(--display);
  font-weight: 500;
  letter-spacing: -0.055em;
}

.hero-deck {
  max-width: 630px;
  margin: 42px 0 0;
  font-size: clamp(22px, 2.2vw, 31px);
  font-weight: 500;
  letter-spacing: -0.035em;
  line-height: 1.25;
}

.hero-note {
  max-width: 580px;
  margin: 20px 0 0;
  color: var(--muted);
  font-size: 15px;
}

.hero-actions {
  display: flex;
  gap: 26px;
  align-items: center;
  margin-top: 38px;
}

.button {
  display: inline-flex;
  min-height: 52px;
  gap: 34px;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  border: 1px solid var(--ink);
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  transition:
    transform var(--transition),
    box-shadow var(--transition),
    background var(--transition);
}

.button svg {
  width: 18px;
  height: 18px;
}

.button-primary {
  background: var(--signal);
  box-shadow: 5px 5px 0 var(--ink);
}

.button-primary:hover {
  box-shadow: 2px 2px 0 var(--ink);
  transform: translate(3px, 3px);
}

.text-link {
  border-bottom: 1px solid currentColor;
  color: var(--ink-soft);
  font-size: 13px;
  font-weight: 600;
}

.cleaner-panel {
  position: relative;
  background: var(--ink);
  box-shadow: var(--shadow-hard);
  color: var(--paper-bright);
}

.cleaner-panel::before {
  position: absolute;
  z-index: -1;
  top: -13px;
  right: -13px;
  width: 68%;
  height: 62%;
  border: 1px solid var(--line-strong);
  content: "";
}

.panel-bar,
.panel-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 42px;
  padding: 0 18px;
  border-color: rgba(255, 255, 255, 0.14);
  color: rgba(255, 255, 255, 0.58);
}

.panel-bar {
  border-bottom: 1px solid;
}

.panel-footer {
  border-top: 1px solid;
  font-size: 9px;
}

.panel-live {
  display: flex;
  gap: 7px;
  align-items: center;
  color: var(--signal);
}

.panel-live i {
  width: 6px;
  height: 6px;
  background: currentColor;
}

.cleaner-body {
  padding: 24px;
}

.panel-intro {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  margin-bottom: 20px;
}

.panel-index {
  display: grid;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.25);
  color: var(--signal);
  font-family: var(--mono);
  font-size: 10px;
}

.panel-kicker {
  margin: 0 0 2px;
  color: var(--paper-bright);
}

.panel-description {
  margin: 0;
  color: rgba(255, 255, 255, 0.5);
  font-size: 12px;
}

.dropzone {
  position: relative;
  display: flex;
  min-height: 250px;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 1px dashed rgba(255, 255, 255, 0.28);
  background:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 22px 22px;
  text-align: center;
  transition:
    border-color var(--transition),
    background-color var(--transition);
}

.dropzone:hover,
.dropzone.is-dragging {
  border-color: var(--signal);
  background-color: rgba(185, 255, 102, 0.06);
}

.dropzone input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
}

.dropzone-corners::before,
.dropzone-corners::after {
  position: absolute;
  width: 18px;
  height: 18px;
  border-color: var(--signal);
  border-style: solid;
  content: "";
}

.dropzone-corners::before {
  top: -1px;
  left: -1px;
  border-width: 2px 0 0 2px;
}

.dropzone-corners::after {
  right: -1px;
  bottom: -1px;
  border-width: 0 2px 2px 0;
}

.dropzone-icon {
  display: grid;
  width: 58px;
  height: 58px;
  margin-bottom: 20px;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.22);
  color: var(--signal);
}

.dropzone strong {
  font-size: 17px;
  letter-spacing: -0.02em;
}

.dropzone > span:not(.dropzone-corners, .dropzone-icon) {
  margin-top: 4px;
  color: rgba(255, 255, 255, 0.5);
  font-size: 12px;
}

.dropzone small {
  margin-top: 24px;
  color: rgba(255, 255, 255, 0.42);
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.06em;
}

.file-preview {
  display: grid;
  min-height: 88px;
  grid-template-columns: 64px 1fr auto;
  gap: 14px;
  align-items: center;
  padding: 11px;
  border: 1px solid rgba(185, 255, 102, 0.38);
  background: rgba(185, 255, 102, 0.06);
}

.file-preview[hidden] {
  display: none;
}

.file-thumbnail {
  width: 64px;
  height: 64px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.08);
}

.file-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.file-meta {
  display: flex;
  min-width: 0;
  flex-direction: column;
}

.file-meta strong {
  overflow: hidden;
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-meta span {
  margin-top: 4px;
  color: rgba(255, 255, 255, 0.45);
  font-family: var(--mono);
  font-size: 9px;
}

.remove-file {
  display: grid;
  width: 32px;
  height: 32px;
  cursor: pointer;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: transparent;
  color: var(--paper-bright);
}

.remove-file:hover {
  border-color: var(--warning);
  color: var(--warning);
}

.remove-file svg {
  width: 15px;
  height: 15px;
}

.local-proof {
  display: flex;
  gap: 12px;
  align-items: center;
  margin-top: 18px;
  padding: 14px 0 0;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.local-proof svg {
  width: 20px;
  height: 20px;
  color: var(--signal);
}

.local-proof div {
  display: flex;
  flex-direction: column;
}

.local-proof strong {
  font-size: 11px;
}

.local-proof span {
  color: rgba(255, 255, 255, 0.46);
  font-size: 10px;
}

.trust-strip {
  position: relative;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
}

.trust-strip > div {
  display: flex;
  min-height: 96px;
  flex-direction: column;
  justify-content: center;
  padding-left: 24px;
  border-left: 1px solid var(--line);
}

.trust-strip > div:last-child {
  border-right: 1px solid var(--line);
}

.trust-strip strong {
  font-family: var(--mono);
  font-size: 18px;
  line-height: 1;
}

.trust-strip span {
  margin-top: 8px;
  color: var(--muted);
  font-size: 11px;
}

.section {
  padding: 120px 0;
}

.section-heading {
  display: grid;
  grid-template-columns: 0.55fr 1.45fr;
  gap: 70px;
  margin-bottom: 64px;
}

.section-number {
  margin: 8px 0 0;
  color: var(--muted);
}

.section-number.light {
  color: rgba(255, 255, 255, 0.5);
}

.section-heading h2,
.process-header h2,
.boundary-copy h2,
.faq-intro h2 {
  max-width: 780px;
  margin: 0;
  font-size: clamp(42px, 5vw, 72px);
  font-weight: 500;
  letter-spacing: -0.055em;
  line-height: 1.02;
}

.section-heading > div > p {
  max-width: 580px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 16px;
}

.evidence-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line-strong);
  border-left: 1px solid var(--line);
}

.evidence-item {
  position: relative;
  min-height: 280px;
  padding: 28px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  transition:
    background var(--transition),
    color var(--transition);
}

.evidence-item:hover {
  background: var(--ink);
  color: var(--paper-bright);
}

.evidence-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10px;
}

.evidence-top svg {
  width: 27px;
  height: 27px;
}

.evidence-item:hover .evidence-top,
.evidence-item:hover p {
  color: rgba(255, 255, 255, 0.58);
}

.evidence-item h3 {
  margin: 64px 0 12px;
  font-size: 23px;
  letter-spacing: -0.035em;
}

.evidence-item p {
  max-width: 310px;
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.evidence-item small {
  position: absolute;
  right: 28px;
  bottom: 24px;
  left: 28px;
  color: var(--muted);
  font-size: 9px;
}