:root {
  --green: #0B6E4F;
  --green-deep: #084B36;
  --orange: #F25C05;
  --gold: #C9A24B;
  --deep-blue: #1D2D44;
  --mist: #E4F0EB;
  --paper: #F6EEDF;
  --night: #0F1A2C;
  --line: #8C9BAB;
  --white: #FFFFFF;
  --body-font: "Source Han Sans CN", "PingFang SC", "Microsoft YaHei", sans-serif;
  --head-font: "Noto Sans SC", var(--body-font);
  --num-font: "DIN Alternate", "Arial Narrow", sans-serif;
  --radius: 4px;
  --shadow: 0 10px 24px rgba(15, 26, 44, .10);
  --header-h: 72px;
  --content-w: 1240px;
  --gutter: clamp(1rem, 4vw, 2.5rem);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--body-font);
  font-size: 1rem;
  line-height: 1.8;
  color: var(--night);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

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

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

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

.container {
  width: min(var(--content-w), calc(100% - var(--gutter) * 2));
  margin: 0 auto;
}

.skip-link {
  position: fixed;
  top: -4rem;
  left: 1rem;
  z-index: 10000;
  background: var(--orange);
  color: #fff;
  padding: .6rem 1.4rem;
  font-weight: 700;
  border-radius: var(--radius);
  transition: top .2s;
}

.skip-link:focus-visible {
  top: .5rem;
}

:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
}

::selection {
  background: var(--gold);
  color: var(--night);
}

/* 头部 */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: transparent;
  color: #fff;
  transition: background .3s, box-shadow .3s;
}

.site-header[data-scrolled] {
  background: var(--deep-blue);
  box-shadow: 0 6px 20px rgba(0, 0, 0, .15);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.brand-word {
  display: flex;
  align-items: center;
  gap: .7rem;
  font-family: var(--head-font);
  font-weight: 900;
  font-size: 1.35rem;
  letter-spacing: .02em;
  white-space: nowrap;
}

.brand-mark {
  display: block;
  width: 26px;
  height: 26px;
  border: 2px solid var(--gold);
  transform: rotate(45deg);
  border-radius: 3px;
  position: relative;
}

.brand-mark::after {
  content: "";
  position: absolute;
  inset: 4px;
  background: var(--orange);
  border-radius: 1px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.4rem;
}

.site-nav a {
  font-size: .92rem;
  font-weight: 500;
  padding: .4rem .4rem .5rem;
  position: relative;
  color: rgba(255, 255, 255, .88);
  border-bottom: 2px solid transparent;
  transition: color .2s, border-color .2s;
}

.site-nav a:hover {
  color: #fff;
  border-color: var(--orange);
}

.site-nav a[aria-current="page"] {
  color: #fff;
  border-color: var(--gold);
  font-weight: 700;
}

.site-nav .nav-energy {
  background: var(--orange);
  color: #fff;
  padding: .5rem 1.2rem;
  border-radius: var(--radius);
  font-weight: 700;
  border: none;
}

.site-nav .nav-energy:hover {
  background: #d94e02;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: .5rem;
  color: #fff;
  font-weight: 700;
  padding: .5rem .8rem;
  border: 1px solid rgba(255, 255, 255, .4);
  border-radius: var(--radius);
}

.nav-toggle-box {
  display: block;
  width: 18px;
  height: 12px;
  position: relative;
}

.nav-toggle-box::before,
.nav-toggle-box::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: #fff;
  transition: transform .2s, top .2s;
}

.nav-toggle-box::before {
  top: 0;
}

.nav-toggle-box::after {
  top: auto;
  bottom: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-box::before {
  top: 5px;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-box::after {
  bottom: 5px;
  transform: rotate(-45deg);
}

@media (max-width: 900px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--deep-blue);
    padding: .8rem var(--gutter) 1.2rem;
    box-shadow: 0 20px 30px rgba(0, 0, 0, .2);
    transform: translateY(-120%);
    transition: transform .25s;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
    z-index: 999;
  }

  .site-nav[data-open] {
    transform: translateY(0);
  }

  .site-nav a {
    padding: .9rem .4rem;
    border-bottom: 1px solid rgba(255, 255, 255, .1);
    border-left: 3px solid transparent;
    font-size: 1rem;
  }

  .site-nav a:hover {
    border-left-color: var(--orange);
  }

  .site-nav a[aria-current="page"] {
    border-left-color: var(--gold);
  }

  .site-nav .nav-energy {
    border-left: none;
    margin-top: .6rem;
    text-align: center;
  }
}

/* 页脚 */
.site-footer {
  background: var(--deep-blue);
  color: rgba(255, 255, 255, .85);
  margin-top: 6rem;
  padding: 4rem 0 2rem;
  position: relative;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--orange) 0%, var(--gold) 50%, var(--green) 100%);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.2fr;
  gap: 2.5rem 3rem;
  margin-bottom: 3rem;
}

.footer-brand p + p {
  margin-top: 1rem;
}

.footer-tagline {
  font-family: var(--head-font);
  font-weight: 900;
  font-size: 1.35rem;
  color: #fff;
}

.footer-trust {
  font-size: .9rem;
  max-width: 34rem;
  opacity: .75;
}

.footer-links {
  display: flex;
  flex-direction: column;
  flex-wrap: wrap;
  max-height: 9.5rem;
  column-gap: 1.6rem;
}

.footer-links a {
  color: rgba(255, 255, 255, .8);
  padding: .3rem 0;
  font-size: .95rem;
  border-bottom: 1px solid transparent;
}

.footer-links a:hover {
  color: #fff;
  border-color: var(--gold);
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: .4rem;
  font-size: .95rem;
}

.footer-contact-main {
  color: #fff;
  font-weight: 700;
  font-size: 1.05rem;
}

.footer-phone {
  color: var(--gold);
  font-weight: 700;
  letter-spacing: .02em;
}

.footer-meta {
  border-top: 1px solid rgba(255, 255, 255, .12);
  padding-top: 1.8rem;
  display: flex;
  flex-wrap: wrap;
  gap: .8rem 2rem;
  align-items: center;
  font-size: .82rem;
  opacity: .7;
}

.footer-copy {
  color: #fff;
}

.footer-echo {
  margin-left: auto;
  font-style: italic;
}

@media (max-width: 760px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .footer-links {
    max-height: none;
    flex-direction: row;
    gap: .4rem 1rem;
  }

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

  .footer-echo {
    margin-left: 0;
  }
}

/* 通用按钮 */
.btn-energy {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  background: var(--orange);
  color: #fff;
  font-weight: 800;
  padding: .95rem 1.9rem;
  border-radius: var(--radius);
  border: 1px solid transparent;
  transition: background .2s, transform .2s, box-shadow .2s;
  font-size: 1rem;
}

.btn-energy:hover {
  background: #d94e02;
  transform: translateY(-2px);
  box-shadow: 0 12px 24px rgba(242, 92, 5, .3);
}

/* 章节标签 */
.section-label {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--green);
}

.section-label::before {
  content: "";
  width: 2.4rem;
  height: 2px;
  background: var(--gold);
}

.section-number {
  font-family: var(--num-font);
  font-size: clamp(3.5rem, 8vw, 6.5rem);
  line-height: .9;
  font-weight: 700;
  color: var(--deep-blue);
  opacity: .9;
}

/* 首屏框景 */
.frame-stage {
  position: relative;
  background: var(--deep-blue);
  color: #fff;
  padding: calc(var(--header-h) + 3rem) 0 4rem;
  overflow: hidden;
}

.frame-stage::before {
  content: "";
  position: absolute;
  inset: 1.2rem;
  border: 2px solid var(--gold);
  border-radius: 3px;
  pointer-events: none;
}

.frame-stage .frame-content {
  position: relative;
  z-index: 2;
}

.frame-stage .frame-ticks {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: .4;
}

.frame-ticks span {
  position: absolute;
  background: var(--line);
}

.frame-ticks span:nth-child(1) {
  top: 0;
  left: 1.2rem;
  width: 60px;
  height: 1px;
}

.frame-ticks span:nth-child(2) {
  bottom: 0;
  left: 1.2rem;
  width: 60px;
  height: 1px;
}

.frame-ticks span:nth-child(3) {
  top: 1.2rem;
  right: 0;
  height: 60px;
  width: 1px;
}

.frame-ticks span:nth-child(4) {
  bottom: 1.2rem;
  right: 0;
  height: 60px;
  width: 1px;
}

/* 趋势线 */
.trend-line {
  position: relative;
  height: 3px;
  background: transparent;
  overflow: hidden;
  margin: 2rem 0;
}

.trend-line::before {
  content: "";
  position: absolute;
  top: 0;
  left: -20%;
  height: 3px;
  width: 40%;
  background: var(--gold);
  border-radius: 2px;
  animation: trend-slide 4s ease-in-out infinite;
}

@keyframes trend-slide {
  0% {
    left: -20%;
    opacity: .4;
  }
  50% {
    opacity: 1;
  }
  100% {
    left: 100%;
    opacity: .4;
  }
}

@media (prefers-reduced-motion: reduce) {
  .trend-line::before {
    animation: none;
    left: 0;
    width: 60%;
  }
}

/* 纸张卡片 */
.paper-card {
  background: var(--mist);
  border: 1px solid rgba(11, 110, 79, .25);
  border-radius: var(--radius);
  padding: 1.8rem;
  box-shadow: 0 4px 16px rgba(0, 0, 0, .05);
  transition: transform .2s, box-shadow .2s;
}

.paper-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 30px rgba(0, 0, 0, .12);
}

/* 图片容器基础规则 */
.pic-container {
  position: relative;
  overflow: hidden;
  background: var(--green-deep);
}

.pic-container img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .4s ease;
}

.pic-container:hover img {
  transform: scale(1.03);
}

.pic-ratio-wide {
  aspect-ratio: 16 / 9;
}

.pic-ratio-portrait {
  aspect-ratio: 4 / 5;
}

/* 内容工具 */
.content-wrap {
  padding: 4rem 0 2rem;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem .8rem;
  font-size: .88rem;
  color: var(--line);
  margin-bottom: 2rem;
}

.breadcrumb a {
  color: var(--green);
  font-weight: 600;
}

.breadcrumb a:hover {
  color: var(--orange);
}

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

@media (max-width: 860px) {
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
}

/* 揭示动画与返回顶部 */
[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .4s ease, transform .4s ease;
}

[data-reveal].revealed {
  opacity: 1;
  transform: none;
}

.scroll-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: var(--deep-blue);
  color: #fff;
  border: 1px solid var(--gold);
  border-radius: 50%;
  opacity: 0;
  visibility: hidden;
  transition: opacity .3s, visibility .3s, background .2s;
}

.scroll-top[data-shown] {
  opacity: 1;
  visibility: visible;
}

.scroll-top:hover {
  background: var(--green);
}

.scroll-top svg {
  width: 18px;
  height: 18px;
  stroke: currentColor;
  stroke-width: 2.5;
  fill: none;
  stroke-linecap: round;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .site-header,
  .site-nav,
  .scroll-top,
  .paper-card,
  .pic-container img {
    transition: none;
  }
}