/* =========================================================================
   深研 DeepResearch · 多租户调研 SaaS 平台 — 官网样式
   四川深研数据科技有限公司
   零依赖纯 CSS，浅色主题
   ========================================================================= */

/* ------------------------------ 设计变量 ------------------------------ */
:root {
  --color-primary: #1D4ED8;
  --color-primary-dark: #1E40AF;
  --color-primary-light: #EFF4FF;
  --color-accent: #0EA5E9;
  --color-text: #0F172A;
  --color-text-2: #475569;
  --color-text-3: #64748B;
  --color-bg: #F8FAFC;
  --color-surface: #FFFFFF;
  --color-border: #E2E8F0;
  --color-border-strong: #CBD5E1;

  --radius-sm: 10px;
  --radius: 14px;
  --radius-lg: 18px;
  --radius-pill: 999px;

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04), 0 1px 3px rgba(15, 23, 42, 0.06);
  --shadow: 0 4px 14px rgba(15, 23, 42, 0.06), 0 1px 3px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 18px 40px rgba(15, 23, 42, 0.10);

  --container: 1160px;
  --header-h: 68px;

  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei",
    "Hiragino Sans GB", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

/* ------------------------------ 基础重置 ------------------------------ */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 12px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4 {
  margin: 0;
  line-height: 1.3;
  font-weight: 700;
  color: var(--color-text);
}

p {
  margin: 0;
}

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s ease, opacity 0.2s ease;
}

a:hover {
  color: var(--color-primary-dark);
}

img,
svg {
  display: block;
  max-width: 100%;
}

/* 跳转链接（无障碍） */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 999;
  padding: 10px 16px;
  background: var(--color-primary);
  color: #fff;
  border-radius: 0 0 var(--radius-sm) 0;
}

.skip-link:focus {
  left: 0;
  color: #fff;
}

/* ------------------------------ 布局容器 ------------------------------ */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ------------------------------ 按钮 ------------------------------ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.2;
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.18s ease, box-shadow 0.18s ease,
    background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #fff;
  box-shadow: 0 6px 16px rgba(29, 78, 216, 0.24);
}

.btn-primary:hover {
  background-color: var(--color-primary-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 10px 22px rgba(29, 78, 216, 0.30);
}

.btn-ghost {
  background-color: #fff;
  color: var(--color-primary);
  border-color: var(--color-border-strong);
}

.btn-ghost:hover {
  color: var(--color-primary-dark);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.btn-block {
  width: 100%;
}

.btn[aria-disabled="true"] {
  cursor: default;
}

/* ------------------------------ 顶部导航 ------------------------------ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--color-text);
  flex-shrink: 0;
}

.brand:hover {
  color: var(--color-text);
}

.brand-mark {
  display: inline-flex;
  line-height: 0;
  border-radius: 9px;
  overflow: hidden;
  box-shadow: 0 4px 10px rgba(29, 78, 216, 0.22);
}

.brand-mark img {
  display: block;
  width: 32px;
  height: 32px;
  object-fit: contain;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-text strong {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand-text small {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-3);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-list a {
  position: relative;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text-2);
  padding: 6px 0;
}

.nav-list a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  border-radius: 2px;
  background-color: var(--color-primary);
  transition: width 0.22s ease;
}

.nav-list a:hover {
  color: var(--color-primary);
}

.nav-list a:hover::after {
  width: 100%;
}

/* 汉堡菜单（纯 CSS checkbox） */
.nav-toggle-input {
  display: none;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  padding: 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: #fff;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  border-radius: 2px;
  background-color: var(--color-text);
  transition: transform 0.24s ease, opacity 0.24s ease;
}

/* ------------------------------ Hero ------------------------------ */
.hero {
  position: relative;
  padding: 84px 0 88px;
  background:
    radial-gradient(900px 420px at 88% -8%, rgba(14, 165, 233, 0.14), transparent 62%),
    radial-gradient(760px 400px at 4% 12%, rgba(29, 78, 216, 0.10), transparent 60%),
    var(--color-bg);
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  align-items: center;
  gap: 56px;
}

.hero-eyebrow {
  display: inline-block;
  margin-bottom: 18px;
  padding: 6px 14px;
  border: 1px solid rgba(29, 78, 216, 0.22);
  border-radius: var(--radius-pill);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.hero-title {
  font-size: 52px;
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.18;
}

.hero-subtitle {
  margin-top: 22px;
  max-width: 560px;
  font-size: 17px;
  color: var(--color-text-2);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 32px;
}

.hero-points {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 26px;
  margin-top: 34px;
  padding-top: 26px;
  border-top: 1px solid var(--color-border);
}

.hero-points li {
  position: relative;
  padding-left: 22px;
  font-size: 14px;
  color: var(--color-text-2);
}

.hero-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background-color: rgba(29, 78, 216, 0.12);
  box-shadow: inset 0 0 0 2px var(--color-primary);
}

.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
  filter: drop-shadow(0 24px 48px rgba(15, 23, 42, 0.10));
}

/* ------------------------------ 通用区块 ------------------------------ */
.section {
  padding: 88px 0;
}

.section-alt {
  background-color: #fff;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.section-head {
  max-width: 720px;
  margin: 0 auto 52px;
  text-align: center;
}

.section-eyebrow {
  margin-bottom: 12px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary);
}

.section-title {
  font-size: 34px;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.section-desc {
  margin-top: 16px;
  font-size: 16px;
  color: var(--color-text-2);
}

/* ------------------------------ 卡片 ------------------------------ */
.card {
  position: relative;
  padding: 30px 26px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform 0.24s ease, box-shadow 0.24s ease,
    border-color 0.24s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(29, 78, 216, 0.28);
}

.card h3 {
  margin-bottom: 12px;
  font-size: 18px;
  font-weight: 700;
}

.card p {
  font-size: 14.5px;
  color: var(--color-text-2);
}

.card-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  margin-bottom: 18px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(29, 78, 216, 0.12), rgba(14, 165, 233, 0.14));
  color: var(--color-primary);
}

/* ------------------------------ 产品能力网格 ------------------------------ */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

/* ------------------------------ 数据统计条 ------------------------------ */
.stats {
  padding: 54px 0;
  background: linear-gradient(120deg, #1D4ED8 0%, #1E40AF 55%, #0EA5E9 130%);
}

.stats-inner {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

.stat strong {
  display: block;
  font-size: 34px;
  font-weight: 800;
  color: #fff;
  letter-spacing: -0.01em;
}

.stat span {
  display: block;
  margin-top: 6px;
  font-size: 14px;
  color: rgba(255, 255, 255, 0.82);
}

/* ------------------------------ 解决方案网格 ------------------------------ */
.solution-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
}

.solution-card {
  border-top: 3px solid transparent;
  background-image: linear-gradient(#fff, #fff),
    linear-gradient(120deg, var(--color-primary), var(--color-accent));
  background-origin: border-box;
  background-clip: padding-box, border-box;
}

.solution-card h3 {
  font-size: 17px;
}

.solution-card p {
  font-size: 14.5px;
  color: var(--color-text-2);
}

/* ------------------------------ 关于我们 ------------------------------ */
.about-layout {
  display: grid;
  grid-template-columns: 1.35fr 0.85fr;
  gap: 48px;
  align-items: start;
}

.about-copy p {
  margin-bottom: 18px;
  font-size: 16px;
  color: var(--color-text-2);
}

.about-copy p:last-child {
  margin-bottom: 0;
}

.about-info {
  padding: 28px 26px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.info-list li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px dashed var(--color-border);
}

.info-list li:first-child {
  padding-top: 0;
}

.info-list li:last-child {
  padding-bottom: 0;
  border-bottom: none;
}

.info-label {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--color-text-3);
}

.info-value {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
}

/* ------------------------------ 联系我们 ------------------------------ */
.contact-layout {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 48px;
  align-items: start;
}

.contact-list li {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--color-border);
}

.contact-list li:first-child {
  padding-top: 0;
}

.contact-list li:last-child {
  border-bottom: none;
}

.contact-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

.contact-label {
  display: block;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--color-text-3);
}

.contact-value {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
  word-break: break-all;
}

.contact-form-wrap {
  padding: 30px 28px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.form-note {
  margin-bottom: 22px;
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-light);
  color: var(--color-primary-dark);
  font-size: 13.5px;
  line-height: 1.6;
}

.form-row {
  margin-bottom: 18px;
}

.form-row label {
  display: block;
  margin-bottom: 7px;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--color-text-2);
}

.form-row input,
.form-row textarea {
  width: 100%;
  padding: 11px 14px;
  font-family: inherit;
  font-size: 14.5px;
  color: var(--color-text);
  background-color: #fff;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-row textarea {
  resize: vertical;
  min-height: 96px;
}

.form-row input::placeholder,
.form-row textarea::placeholder {
  color: #94A3B8;
}

.form-row input:focus,
.form-row textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(29, 78, 216, 0.14);
}

/* ------------------------------ 页脚 ------------------------------ */
.site-footer {
  background-color: #fff;
  border-top: 1px solid var(--color-border);
}

.footer-top {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  padding-top: 60px;
  padding-bottom: 40px;
}

.footer-desc {
  margin-top: 16px;
  max-width: 340px;
  font-size: 14.5px;
  color: var(--color-text-2);
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.footer-col h3 {
  margin-bottom: 14px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--color-text);
}

.footer-col ul li {
  margin-bottom: 10px;
}

.footer-col a {
  font-size: 14px;
  color: var(--color-text-2);
}

.footer-col a:hover {
  color: var(--color-primary);
}

/* 备案信息区 */
.footer-legal {
  padding-top: 8px;
  padding-bottom: 26px;
}

.legal-list {
  padding: 22px 24px;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.legal-item {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 13.5px;
  color: var(--color-text-2);
  line-height: 1.9;
}

.legal-item + .legal-item {
  margin-top: 6px;
}

.legal-item a {
  font-weight: 600;
}

/* 备案信息链接（ICP / 公安网备），图标与编号整体可点击 */
.beian-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  line-height: 1.6;
  color: inherit;
  text-decoration: none;
  vertical-align: middle;
}

.beian-item:hover,
.beian-item:focus-visible {
  text-decoration: underline;
}

.beian-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  line-height: 0;
  vertical-align: middle;
  color: var(--color-primary);
}

.beian-icon img {
  display: block;
  width: 16px;
  height: 16px;
  object-fit: contain;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  padding-top: 18px;
  padding-bottom: 30px;
  border-top: 1px solid var(--color-border);
}

.footer-status,
.footer-copy {
  font-size: 12.5px;
  color: var(--color-text-3);
}

/* ------------------------------ 滚动进入动画 ------------------------------ */
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.62s ease, transform 0.62s cubic-bezier(0.22, 0.7, 0.3, 1);
  will-change: opacity, transform;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ------------------------------ 响应式：平板 ------------------------------ */
@media (max-width: 1024px) {
  .hero-title {
    font-size: 44px;
  }

  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .solution-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .about-layout,
  .contact-layout {
    grid-template-columns: 1fr;
    gap: 34px;
  }
}

/* ------------------------------ 响应式：移动端 ------------------------------ */
@media (max-width: 768px) {
  :root {
    --header-h: 62px;
  }

  .container {
    padding: 0 18px;
  }

  /* 导航收起为汉堡菜单 */
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px 18px 18px;
    background-color: #fff;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    visibility: hidden;
    transition: max-height 0.28s ease, opacity 0.2s ease, visibility 0.28s ease;
  }

  .nav-toggle-input:checked ~ .site-nav {
    max-height: 460px;
    opacity: 1;
    visibility: visible;
  }

  .nav-toggle-input:checked ~ .nav-toggle span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .nav-toggle-input:checked ~ .nav-toggle span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle-input:checked ~ .nav-toggle span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-list li {
    border-bottom: 1px solid var(--color-border);
  }

  .nav-list a {
    display: block;
    padding: 14px 4px;
    font-size: 15.5px;
  }

  .nav-list a::after {
    display: none;
  }

  .btn-nav {
    margin-top: 16px;
    width: 100%;
  }

  /* Hero */
  .hero {
    padding: 56px 0 64px;
  }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .hero-title {
    font-size: 34px;
  }

  .hero-subtitle {
    font-size: 15.5px;
  }

  .hero-actions .btn {
    flex: 1 1 auto;
  }

  .hero-points {
    gap: 10px 20px;
  }

  /* 区块 */
  .section {
    padding: 60px 0;
  }

  .section-head {
    margin-bottom: 36px;
  }

  .section-title {
    font-size: 26px;
  }

  /* 卡片单列 */
  .feature-grid,
  .solution-grid {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .stats {
    padding: 40px 0;
  }

  .stats-inner {
    grid-template-columns: repeat(2, 1fr);
    gap: 28px 18px;
  }

  .stat strong {
    font-size: 28px;
  }

  .card {
    padding: 24px 20px;
  }

  /* 页脚 */
  .footer-top {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-top: 44px;
    padding-bottom: 28px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .footer-status,
  .footer-copy {
    font-size: 12px;
  }
}

/* ------------------------------ 响应式：小屏 ------------------------------ */
@media (max-width: 420px) {
  .hero-title {
    font-size: 29px;
  }

  .stats-inner {
    grid-template-columns: 1fr;
  }

  .legal-list {
    padding: 18px 16px;
  }
}

/* ------------------------------ 无障碍：减弱动效 ------------------------------ */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .card:hover,
  .btn:hover {
    transform: none;
  }
}