/* ==========================================================================
   关于珀芙研 - 页面专属样式 about.css
   编辑级杂志风：思源宋体大字 + 暖棕墨线 + 巨型衬线数字 + 沉稳留白
   ========================================================================== */

/* --------------------------------------------------------------------------
   关于页变量
   -------------------------------------------------------------------------- */

/* 修复：覆盖 common.css 中 #main-content { overflow: hidden } 的限制，
   确保 about 页面内容区可以独立纵向滚动，不被 Footer 遮挡 */
#main-content.about-page {
  overflow-y: auto;
}

.about-page {
  --about-ink: hsl(25 30% 14%);
  --about-ink-soft: hsl(25 18% 32%);
  --about-line: hsl(25 22% 78%);
  --about-paper: hsl(35 30% 97%);
  --about-paper-2: hsl(33 28% 94%);
  --about-accent: hsl(25 70% 45%);
  --about-accent-deep: hsl(22 65% 32%);

  background-color: var(--about-paper);
  color: var(--about-ink);
}

/* 整体噪点纸张质感 */
.about-page::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  background-image:
    radial-gradient(hsl(25 30% 50% / 0.04) 1px, transparent 1px);
  background-size: 3px 3px;
  mix-blend-mode: multiply;
  opacity: 0.6;
}

/* --------------------------------------------------------------------------
   Banner 区
   -------------------------------------------------------------------------- */
.about-banner {
  position: sticky;
  top: 0;
  z-index: 29;
  height: 200px;
  width: 100%;
  overflow: hidden;
  background-color: var(--about-paper-2);
}

.about-banner__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  filter: saturate(0.85) contrast(0.95);
}

.about-banner__overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(
      90deg,
      hsl(35 30% 97% / 0.92) 0%,
      hsl(35 30% 97% / 0.65) 35%,
      hsl(35 30% 97% / 0.15) 70%,
      transparent 100%
    );
}

.about-banner__rule {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(
    90deg,
    var(--about-line) 0%,
    var(--about-line) 60%,
    transparent 100%
  );
}

.about-banner__inner {
  position: relative;
  z-index: 2;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 0 64px;
  max-width: 1100px;
}

.about-banner__overline {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-style: italic;
  font-size: 14px;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--about-accent);
  margin-bottom: 6px;
}

.about-banner__overline::before {
  content: '';
  width: 28px;
  height: 1px;
  background: var(--about-accent);
}

.about-banner__title {
  font-weight: 500;
  font-size: clamp(32px, 4.2vw, 48px);
  line-height: 1.1;
  letter-spacing: 0.08em;
  color: var(--about-ink);
  margin-bottom: 8px;
}

.about-banner__title em {
  font-style: italic;
  font-weight: 400;
  font-size: 0.5em;
  letter-spacing: 0.15em;
  color: var(--about-ink-soft);
  margin-left: 16px;
  vertical-align: 0.35em;
}

.about-banner__subtitle {
  font-size: 13px;
  color: var(--about-ink-soft);
  letter-spacing: 0.18em;
  font-weight: 300;
}

/* --------------------------------------------------------------------------
   顶部 Tab 导航（吸顶）
   -------------------------------------------------------------------------- */
.about-tabs {
  position: sticky;
  top: 200px;
  z-index: 30;
  background-color: hsl(35 30% 97% / 0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--about-line);
}

.about-tabs__inner {
  display: flex;
  gap: 4px;
  padding: 0 64px;
  overflow-x: auto;
  scrollbar-width: none;
}
.about-tabs__inner::-webkit-scrollbar { display: none; }

.about-tab {
  position: relative;
  flex: 0 0 auto;
  padding: 18px 22px 16px;
  font-size: 14px;
  font-weight: 400;
  letter-spacing: 0.12em;
  color: var(--about-ink-soft);
  background: transparent;
  border: none;
  cursor: pointer;
  white-space: nowrap;
  transition: color 0.3s ease;
}

.about-tab__index {
  font-style: italic;
  font-size: 11px;
  color: var(--about-accent);
  margin-right: 8px;
  letter-spacing: 0.1em;
  opacity: 0.7;
}

.about-tab:hover {
  color: var(--about-ink);
}

.about-tab.is-active {
  color: var(--about-accent-deep);
  font-weight: 500;
}

.about-tab.is-active .about-tab__index {
  opacity: 1;
}

.about-tab::after {
  content: '';
  position: absolute;
  left: 22px;
  right: 22px;
  bottom: -1px;
  height: 2px;
  background: var(--about-accent);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.about-tab.is-active::after {
  transform: scaleX(1);
}

/* --------------------------------------------------------------------------
   Section 通用结构
   -------------------------------------------------------------------------- */
.about-sections {
  position: relative;
  z-index: 2;
}

.about-section {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 96px 64px 64px;
  border-bottom: 1px solid var(--about-line);
  overflow: hidden;
}

.about-section:last-child {
  border-bottom: none;
}

/* 巨型水印数字 */
.about-section__numeral {
  position: absolute;
  top: 28px;
  right: 64px;
  font-style: italic;
  font-weight: 300;
  font-size: clamp(140px, 18vw, 240px);
  line-height: 0.85;
  color: var(--about-paper-2);
  letter-spacing: -0.02em;
  pointer-events: none;
  user-select: none;
  z-index: 0;
}

.about-section__head {
  position: relative;
  z-index: 1;
  margin-bottom: 56px;
  max-width: 900px;
}

.about-section__eyebrow {
  font-style: italic;
  font-size: 13px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--about-accent);
  margin-bottom: 14px;
  display: inline-flex;
  align-items: center;
  gap: 12px;
}

.about-section__eyebrow::before {
  content: '';
  width: 22px;
  height: 1px;
  background: var(--about-accent);
}

.about-section__title {
  font-weight: 500;
  font-size: clamp(28px, 3.4vw, 40px);
  letter-spacing: 0.1em;
  color: var(--about-ink);
  line-height: 1.2;
}

.about-section__body {
  position: relative;
  z-index: 1;
  max-width: 820px;
  flex: 1;
}

.about-section__body p {
  font-weight: 400;
  font-size: 15px;
  line-height: 2;
  letter-spacing: 0.04em;
  color: var(--about-ink);
  margin-bottom: 28px;
  text-align: justify;
}

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

/* 段落首字不做特殊处理 */

/* 滚动提示 */
.about-section__indicator {
  position: relative;
  z-index: 1;
  margin-top: 48px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  color: var(--about-ink-soft);
  animation: aboutBounce 2.4s ease-in-out infinite;
}

.about-section__indicator-text {
  font-style: italic;
  font-size: 12px;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  opacity: 0.6;
}

.about-section__indicator-line {
  width: 1px;
  height: 28px;
  background: linear-gradient(
    180deg,
    transparent 0%,
    var(--about-accent) 100%
  );
}

@keyframes aboutBounce {
  0%, 100% { transform: translateY(0); opacity: 0.7; }
  50% { transform: translateY(8px); opacity: 1; }
}

/* --------------------------------------------------------------------------
   品牌定位 - 引用块强化
   -------------------------------------------------------------------------- */
.about-section--position .about-section__body p:first-of-type {
  position: relative;
  padding-left: 28px;
  border-left: 2px solid var(--about-accent);
  font-size: 17px;
  font-weight: 500;
  color: var(--about-ink);
  margin-bottom: 36px;
}

/* --------------------------------------------------------------------------
   公司重点合作 - 列表
   -------------------------------------------------------------------------- */
.about-coop-list {
  display: grid;
  gap: 40px;
}

.about-coop-item {
  padding-bottom: 36px;
  border-bottom: 1px dashed var(--about-line);
}

.about-coop-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.about-coop-item__text {
  font-size: 15px;
  line-height: 2;
  letter-spacing: 0.04em;
  color: var(--about-ink);
  text-align: justify;
}

.about-coop-item__text strong {
  color: var(--about-accent-deep);
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   核心技术 - 卡片式呈现
   -------------------------------------------------------------------------- */
.about-tech-card {
  position: relative;
  padding: 48px 56px;
  background-color: #fff;
  border: 1px solid var(--about-line);
  box-shadow: 0 1px 0 0 var(--about-line);
}

.about-tech-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: linear-gradient(
    180deg,
    var(--about-accent) 0%,
    var(--about-accent-deep) 100%
  );
}

.about-tech-card__title {
  font-weight: 600;
  font-size: 22px;
  letter-spacing: 0.08em;
  color: var(--about-ink);
  margin-bottom: 24px;
  display: flex;
  align-items: baseline;
  gap: 16px;
}

.about-tech-card__title-en {
  font-style: italic;
  font-weight: 400;
  font-size: 14px;
  letter-spacing: 0.2em;
  color: var(--about-ink-soft);
  text-transform: uppercase;
}

.about-tech-card__text {
  font-size: 15px;
  line-height: 2;
  letter-spacing: 0.04em;
  color: var(--about-ink);
  text-align: justify;
}

.about-tech-pillars {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 40px;
}

.about-tech-pillar {
  padding: 24px 20px;
  background: var(--about-paper);
  border: 1px solid var(--about-line);
  text-align: center;
}

.about-tech-pillar__symbol {
  font-style: italic;
  font-size: 28px;
  color: var(--about-accent);
  line-height: 1;
  margin-bottom: 12px;
}

.about-tech-pillar__name {
  font-weight: 500;
  font-size: 15px;
  letter-spacing: 0.16em;
  color: var(--about-ink);
  margin-bottom: 6px;
}

.about-tech-pillar__desc {
  font-size: 12px;
  color: var(--about-ink-soft);
  letter-spacing: 0.08em;
}

/* --------------------------------------------------------------------------
   独家专利成分
   -------------------------------------------------------------------------- */
.about-patent-feature {
  position: relative;
  padding: 40px 0 40px 36px;
  border-left: 3px solid var(--about-accent);
  margin-bottom: 48px;
}

.about-patent-feature__name {
  font-weight: 600;
  font-size: 26px;
  letter-spacing: 0.06em;
  color: var(--about-ink);
  margin-bottom: 8px;
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 12px;
}

.about-patent-feature__name-en {
  font-style: italic;
  font-weight: 400;
  font-size: 16px;
  letter-spacing: 0.18em;
  color: var(--about-accent);
  text-transform: uppercase;
}

.about-patent-feature__no {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--about-ink-soft);
  background: var(--about-paper-2);
  padding: 4px 12px;
  margin-bottom: 22px;
  border: 1px solid var(--about-line);
}

.about-patent-feature__desc {
  font-size: 15px;
  line-height: 2;
  letter-spacing: 0.04em;
  color: var(--about-ink);
  text-align: justify;
  max-width: 820px;
}

.about-patent-doc {
  background: #fff;
  border: 1px solid var(--about-line);
  overflow: hidden;
  max-width: 900px;
}

.about-patent-doc__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background: var(--about-paper-2);
  border-bottom: 1px solid var(--about-line);
}

.about-patent-doc__label {
  font-weight: 500;
  font-size: 13px;
  letter-spacing: 0.18em;
  color: var(--about-ink);
}

.about-patent-doc__download {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-style: italic;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--about-accent);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.about-patent-doc__download:hover {
  color: var(--about-accent-deep);
  border-bottom-color: var(--about-accent-deep);
}

.about-patent-doc__viewer {
  width: 100%;
  border: 0;
  display: block;
  background: var(--about-paper-2);
}

/* --------------------------------------------------------------------------
   入场动画
   -------------------------------------------------------------------------- */
.about-section__head,
.about-section__body > * {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.9s cubic-bezier(0.2, 0.6, 0.2, 1),
    transform 0.9s cubic-bezier(0.2, 0.6, 0.2, 1);
}

.about-section.is-visible .about-section__head {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.05s;
}

.about-section.is-visible .about-section__body > * {
  opacity: 1;
  transform: translateY(0);
}

.about-section.is-visible .about-section__body > *:nth-child(1) { transition-delay: 0.15s; }
.about-section.is-visible .about-section__body > *:nth-child(2) { transition-delay: 0.25s; }
.about-section.is-visible .about-section__body > *:nth-child(3) { transition-delay: 0.35s; }
.about-section.is-visible .about-section__body > *:nth-child(4) { transition-delay: 0.45s; }
.about-section.is-visible .about-section__body > *:nth-child(5) { transition-delay: 0.55s; }

/* --------------------------------------------------------------------------
   响应式
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
  .about-banner__inner,
  .about-tabs__inner,
  .about-section {
    padding-left: 40px;
    padding-right: 40px;
  }
  .about-section__numeral { right: 40px; }
  .about-tech-pillars { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  /* 移动端不创建独立滚动容器，让页面在视口级别滚动，sticky 基于视口生效 */
  #main-content.about-page {
    overflow: visible;
  }
  .about-banner { height: 180px; }
  .about-tabs { top: 180px; }
  .about-banner__inner,
  .about-tabs__inner {
    padding-left: 20px;
    padding-right: 20px;
  }
  .about-section {
    padding: 64px 20px 48px;
    min-height: auto;
  }
  .about-section__numeral {
    right: 20px;
    font-size: 100px;
    top: 16px;
  }
  .about-section__head { margin-bottom: 36px; }
  .about-tab { padding: 14px 14px 12px; font-size: 13px; }
  .about-tab::after { left: 14px; right: 14px; }
  .about-tech-card { padding: 32px 24px 32px 28px; }
  .about-tech-card__title {
    flex-direction: column;
    gap: 6px;
    align-items: flex-start;
  }
  .about-patent-feature {
    padding: 24px 0 24px 20px;
  }
  .about-patent-feature__name { font-size: 22px; }

  /* 标签导航可横向滚动 */
  .about-tabs__inner {
    padding: 0 16px;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  .about-tabs__inner::-webkit-scrollbar { display: none; }
  .about-tab {
    white-space: nowrap;
    flex-shrink: 0;
  }

  /* 水印数字缩小 */
  .about-section__numeral {
    font-size: 60px !important;
    opacity: 0.03;
  }

  /* 段落取消两端对齐 */
  .about-section p,
  .about-section__body p {
    text-align: left;
  }
}