/* ========================================
   青岛芯能优控电力科技有限公司 - 企业官网
   Design Tokens / Base / Layout / Components / Page
   ======================================== */

/* ========== 1. CSS Variables (Design Tokens) ========== */
:root {
  /* Colors */
  --color-primary: #1a73e8;
  --color-primary-dark: #0d47a1;
  --color-primary-light: #4fc3f7;
  --color-gradient-start: #1a73e8;
  --color-gradient-end: #0d47a1;
  --color-bg-white: #ffffff;
  --color-bg-light: #f5f8fc;
  --color-bg-dark: #0a1628;
  --color-text-primary: #1a1a2e;
  --color-text-body: #4a4a5a;
  --color-text-light: #8a8a9a;
  --color-text-white: #ffffff;
  --color-border: #e8ecf2;
  --color-accent: #00c9a7;

  /* Typography */
  --font-primary: 'Source Han Sans SC', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-h1: 48px;
  --font-size-h2: 36px;
  --font-size-h3: 24px;
  --font-size-h4: 20px;
  --font-size-body: 16px;
  --font-size-small: 14px;
  --font-size-caption: 12px;
  --line-height-h1: 1.2;
  --line-height-h2: 1.3;
  --line-height-h3: 1.4;
  --line-height-h4: 1.5;
  --line-height-body: 1.8;
  --line-height-small: 1.6;

  /* Spacing */
  --spacing-section: 100px;
  --spacing-module: 60px;
  --spacing-card: 24px;
  --spacing-gap: 32px;
  --container-max: 1500px;
  --container-padding: 40px;

  /* Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.15);

  /* Transitions */
  --transition-fast: 200ms ease;
  --transition-normal: 300ms ease;
  --transition-slow: 400ms ease;
  --transition-enter: 600ms ease-out;
}

/* ========== 2. Reset & Base ========== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-primary);
  font-size: var(--font-size-body);
  line-height: var(--line-height-body);
  color: var(--color-text-body);
  background-color: var(--color-bg-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  text-decoration: none;
  color: inherit;
  transition: color var(--transition-fast);
}

ul,
ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--color-text-primary);
  font-weight: 700;
}

/* ========== 3. Layout ========== */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.section {
  padding: var(--spacing-section) 0;
}

.section--light {
  background-color: var(--color-bg-light);
}

.section--dark {
  background-color: var(--color-bg-dark);
  color: var(--color-text-white);
}

.section--dark .section-title,
.section--dark .section-subtitle {
  color: var(--color-text-white);
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-module);
}

.section-title {
  font-size: var(--font-size-h2);
  line-height: var(--line-height-h2);
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: var(--font-size-body);
  color: var(--color-text-light);
  max-width: 700px;
  margin: 0 auto;
}

/* ========== 4. Header ========== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(232, 236, 242, 0.6);
  transition: box-shadow var(--transition-normal);
}

.header--scrolled {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.header__logo {
  display: flex;
  align-items: center;
  transition: opacity var(--transition-fast);
}

.header__logo:hover {
  opacity: 0.85;
}

.header__logo img {
  height: 40px;
  width: auto;
}

.header__logo span {
  color: var(--color-primary-light);
}

.header__nav {
  display: flex;
  align-items: center;
  gap: 36px;
}

.header__nav-list {
  display: flex;
  align-items: center;
  gap: 32px;
}

.header__nav-item {
  position: relative;
}

.header__nav-link {
  color: var(--color-text-primary);
  font-size: var(--font-size-small);
  font-weight: 500;
  padding: 8px 0;
  position: relative;
  transition: color var(--transition-fast);
}

.header__nav-link:hover {
  color: var(--color-primary);
}

.header__nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: width var(--transition-normal);
}

.header__nav-link:hover::after {
  width: 100%;
}

/* Dropdown */
.header__dropdown {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(10px);
  background-color: var(--color-bg-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: 12px 0;
  min-width: 180px;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast), transform var(--transition-fast), visibility var(--transition-fast);
}

.header__nav-item:hover .header__dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.header__dropdown-link {
  display: block;
  padding: 10px 20px;
  font-size: var(--font-size-small);
  color: var(--color-text-body);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.header__dropdown-link:hover {
  color: var(--color-primary);
  background-color: var(--color-bg-light);
}

.header__cta {
  padding: 10px 24px;
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  color: var(--color-text-white);
  border: none;
  border-radius: var(--radius-md);
  font-size: var(--font-size-small);
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.header__cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(26, 115, 232, 0.3);
}

/* Hamburger */
.header__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  background: none;
  border: none;
}

.header__hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text-primary);
  transition: transform var(--transition-fast);
}

/* Mobile Nav */
.mobile-nav {
  position: fixed;
  top: 0;
  right: -100%;
  width: 300px;
  height: 100vh;
  background-color: var(--color-bg-white);
  z-index: 2000;
  padding: 80px 24px 24px;
  transition: right var(--transition-normal);
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
}

.mobile-nav--open {
  right: 0;
}

.mobile-nav__close {
  position: absolute;
  top: 24px;
  right: 24px;
  background: none;
  border: none;
  font-size: 28px;
  cursor: pointer;
  color: var(--color-text-primary);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.mobile-nav__link {
  display: block;
  padding: 14px 0;
  font-size: var(--font-size-body);
  color: var(--color-text-primary);
  border-bottom: 1px solid var(--color-border);
  font-weight: 500;
}

.mobile-nav__link:hover {
  color: var(--color-primary);
}

.mobile-nav__sub-link {
  display: block;
  padding: 10px 0 10px 20px;
  font-size: var(--font-size-small);
  color: var(--color-text-body);
  border-bottom: 1px solid var(--color-border);
}

.mobile-nav__sub-link:hover {
  color: var(--color-primary);
}

.mobile-nav__cta {
  display: block;
  margin-top: 24px;
  padding: 14px 24px;
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  color: var(--color-text-white);
  border-radius: var(--radius-md);
  text-align: center;
  font-weight: 600;
}

/* Overlay */
.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1999;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.overlay--visible {
  opacity: 1;
  visibility: visible;
}

/* ========== 5. Hero Section ========== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
}



.hero__content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 900px;
  padding: 0 24px;
}

.hero__title {
  font-size: var(--font-size-h1);
  line-height: var(--line-height-h1);
  color: var(--color-text-white);
  margin-bottom: 20px;
  font-weight: 700;
}

.hero__subtitle {
  font-size: 18px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 40px;
  max-width: 750px;
  margin-left: auto;
  margin-right: auto;
}

.hero__buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ========== 6. Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  border-radius: var(--radius-md);
  font-size: var(--font-size-small);
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-fast);
  white-space: nowrap;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn:active {
  transform: translateY(0);
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn--primary {
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  color: var(--color-text-white);
}

.btn--primary:hover {
  box-shadow: 0 4px 16px rgba(26, 115, 232, 0.35);
}

.btn--outline {
  background-color: transparent;
  border: 2px solid rgba(255, 255, 255, 0.6);
  color: var(--color-text-white);
}

.btn--outline:hover {
  border-color: var(--color-text-white);
  background-color: rgba(255, 255, 255, 0.1);
}

.btn--light {
  background: var(--color-bg-white);
  color: var(--color-primary);
}

.btn--light:hover {
  box-shadow: var(--shadow-md);
}

/* ========== 7. Core Value Section ========== */
.core-value__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-gap);
}

.core-value__item {
  text-align: center;
  padding: 40px 24px;
  background-color: var(--color-bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.core-value__item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.core-value__icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  border-radius: var(--radius-md);
}

.core-value__icon svg {
  width: 32px;
  height: 32px;
  stroke: var(--color-text-white);
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.core-value__title {
  font-size: var(--font-size-h4);
  line-height: var(--line-height-h4);
  margin-bottom: 12px;
}

.core-value__desc {
  font-size: var(--font-size-small);
  line-height: var(--line-height-small);
  color: var(--color-text-body);
}

/* ========== 8. Products Section ========== */
.products__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-gap);
  margin-bottom: 48px;
}

.product-card {
  background-color: var(--color-bg-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.product-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.product-card__image {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.product-card:hover .product-card__image {
  transform: scale(1.05);
}

.product-card__image-wrapper {
  overflow: hidden;
}

.product-card__body {
  padding: var(--spacing-card);
}

.product-card__title {
  font-size: var(--font-size-h4);
  line-height: var(--line-height-h4);
  margin-bottom: 8px;
}

.product-card__desc {
  font-size: var(--font-size-small);
  line-height: var(--line-height-small);
  color: var(--color-text-light);
  margin-bottom: 16px;
}

.product-card__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: var(--font-size-small);
  font-weight: 600;
  color: var(--color-primary);
  transition: gap var(--transition-fast);
}

.product-card__link:hover {
  gap: 10px;
}

.products__footer {
  text-align: center;
}

/* ========== 9. Solutions Section ========== */
.solution-item {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  margin-bottom: 80px;
}

.solution-item:last-child {
  margin-bottom: 0;
}

.solution-item--reverse {
  direction: rtl;
}

.solution-item--reverse > * {
  direction: ltr;
}

.solution-item__image {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.solution-item__content {
  padding: 20px 0;
}

.solution-item__tag {
  display: inline-block;
  padding: 4px 12px;
  background-color: rgba(26, 115, 232, 0.1);
  color: var(--color-primary);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-caption);
  font-weight: 600;
  margin-bottom: 16px;
}

.solution-item__title {
  font-size: var(--font-size-h3);
  line-height: var(--line-height-h3);
  margin-bottom: 16px;
}

.solution-item__desc {
  font-size: var(--font-size-body);
  line-height: var(--line-height-body);
  color: var(--color-text-body);
  margin-bottom: 24px;
}

/* ========== 10. About Brief Section ========== */
.about-brief__inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-brief__content {
  padding: 20px 0;
}

.about-brief__title {
  font-size: var(--font-size-h2);
  line-height: var(--line-height-h2);
  margin-bottom: 8px;
}

.about-brief__subtitle {
  font-size: var(--font-size-body);
  color: var(--color-primary);
  font-weight: 500;
  margin-bottom: 20px;
}

.about-brief__text {
  font-size: var(--font-size-body);
  line-height: var(--line-height-body);
  color: var(--color-text-body);
  margin-bottom: 24px;
}

.about-brief__stats {
  display: flex;
  gap: 40px;
  margin-bottom: 32px;
}

.about-brief__stat-item {
  text-align: center;
}

.about-brief__stat-number {
  font-size: 36px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.2;
}

.about-brief__stat-label {
  font-size: var(--font-size-small);
  color: var(--color-text-light);
}

.about-brief__image {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

/* ========== 11. News Section ========== */
.news__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-gap);
  margin-bottom: 48px;
}

.news-card {
  background-color: var(--color-bg-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.news-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.news-card__image {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.news-card:hover .news-card__image {
  transform: scale(1.05);
}

.news-card__image-wrapper {
  overflow: hidden;
}

.news-card__body {
  padding: var(--spacing-card);
}

.news-card__date {
  font-size: var(--font-size-caption);
  color: var(--color-text-light);
  margin-bottom: 8px;
}

.news-card__title {
  font-size: var(--font-size-h4);
  line-height: var(--line-height-h4);
  margin-bottom: 8px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.news-card__excerpt {
  font-size: var(--font-size-small);
  line-height: var(--line-height-small);
  color: var(--color-text-light);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 16px;
}

.news-card__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: var(--font-size-small);
  font-weight: 600;
  color: var(--color-primary);
  transition: gap var(--transition-fast);
}

.news-card__link:hover {
  gap: 10px;
}

.news__footer {
  text-align: center;
}

/* ========== 12. Final CTA Section ========== */
.final-cta {
  text-align: center;
  padding: 120px 0;
  position: relative;
  overflow: hidden;
}

.final-cta__bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--color-bg-dark) 0%, #0d2137 100%);
  z-index: 0;
}

.final-cta__content {
  position: relative;
  z-index: 1;
}

.final-cta__title {
  font-size: var(--font-size-h2);
  line-height: var(--line-height-h2);
  color: var(--color-text-white);
  margin-bottom: 16px;
}

.final-cta__subtitle {
  font-size: var(--font-size-body);
  color: rgba(255, 255, 255, 0.7);
  margin-bottom: 40px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ========== 13. Footer ========== */
.footer {
  background-color: #060e1a;
  color: rgba(255, 255, 255, 0.7);
  padding: 80px 0 0;
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 60px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer__brand-desc {
  font-size: var(--font-size-small);
  line-height: var(--line-height-small);
  margin-top: 16px;
  max-width: 360px;
}

.footer__title {
  font-size: var(--font-size-small);
  font-weight: 600;
  color: var(--color-text-white);
  margin-bottom: 20px;
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer__link {
  font-size: var(--font-size-small);
  color: rgba(255, 255, 255, 0.6);
  transition: color var(--transition-fast);
}

.footer__link:hover {
  color: var(--color-primary-light);
}

.footer__contact-item {
  font-size: var(--font-size-small);
  margin-bottom: 12px;
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.footer__contact-item svg {
  width: 16px;
  height: 16px;
  stroke: var(--color-primary-light);
  fill: none;
  stroke-width: 2;
  flex-shrink: 0;
  margin-top: 3px;
}

.footer__bottom {
  padding: 24px 0;
  text-align: center;
  font-size: var(--font-size-caption);
  color: rgba(255, 255, 255, 0.4);
}

/* ========== 14. Scroll Animations ========== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--transition-enter), transform var(--transition-enter);
}

.fade-in--visible {
  opacity: 1;
  transform: translateY(0);
}

.fade-in--delay-1 { transition-delay: 100ms; }
.fade-in--delay-2 { transition-delay: 200ms; }
.fade-in--delay-3 { transition-delay: 300ms; }
.fade-in--delay-4 { transition-delay: 400ms; }

/* ========== 15. Responsive ========== */
@media (max-width: 1199px) {
  :root {
    --font-size-h1: 40px;
    --font-size-h2: 32px;
    --spacing-section: 80px;
    --container-padding: 32px;
  }

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

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

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

@media (max-width: 767px) {
  :root {
    --font-size-h1: 32px;
    --font-size-h2: 28px;
    --font-size-h3: 22px;
    --font-size-h4: 18px;
    --spacing-section: 60px;
    --spacing-module: 40px;
    --spacing-gap: 20px;
    --container-padding: 20px;
  }

  .header__nav {
    display: none;
  }

  .header__hamburger {
    display: flex;
  }

  .hero__title {
    font-size: 28px;
  }

  .hero__subtitle {
    font-size: 16px;
  }

  .hero__buttons {
    flex-direction: column;
    align-items: center;
  }

  .core-value__grid {
    grid-template-columns: 1fr;
  }

  .products__grid,
  .news__grid {
    grid-template-columns: 1fr;
  }

  .solution-item {
    grid-template-columns: 1fr;
    gap: 30px;
    margin-bottom: 50px;
  }

  .solution-item--reverse {
    direction: ltr;
  }

  .about-brief__inner {
    grid-template-columns: 1fr;
    gap: 30px;
  }

  .about-brief__stats {
    gap: 24px;
    flex-wrap: wrap;
  }

  .about-brief__stat-number {
    font-size: 28px;
  }

  .footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px 32px;
  }

  .footer__brand {
    grid-column: 1 / -1;
  }

  .footer__col:last-child {
    grid-column: 1 / -1;
  }

  .final-cta {
    padding: 80px 0;
  }
}

/* ========== 16. Accessibility ========== */
@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;
  }

  .fade-in {
    opacity: 1;
    transform: none;
  }
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}
h1.page-hero__title.fade-in { color: #ffffff; }