/* ============================================
   2026 质量强国品质发展大会 - 专题网站样式
   设计基调：庄重、权威、国家级大品牌
   主色：中国红 #C8161D | 辅色：深蓝 #0D2E5C | 点缀：金色 #D4A853
   ============================================ */

/* --- CSS Variables --- */
:root {
  --red: #C8161D;
  --red-dark: #9E1117;
  --red-deep: #7A0B10;
  --navy: #0D2E5C;
  --navy-light: #163D6F;
  --gold: #D4A853;
  --gold-light: #E8C97A;
  --white: #FFFFFF;
  --gray-50: #FAFAFA;
  --gray-100: #F5F5F5;
  --gray-200: #EEEEEE;
  --gray-300: #E0E0E0;
  --gray-600: #666666;
  --gray-800: #333333;
  --gray-900: #1A1A1A;

  --font-cn: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", "Hiragino Sans GB", sans-serif;
  --font-en: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 20px;

  --shadow-sm: 0 2px 8px rgba(0,0,0,.08);
  --shadow-md: 0 4px 20px rgba(0,0,0,.1);
  --shadow-lg: 0 8px 40px rgba(0,0,0,.14);
  --shadow-red: 0 4px 20px rgba(200,22,29,.25);

  --transition: .3s cubic-bezier(.4,0,.2,1);
}

/* --- Reset & Base --- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}
body {
  font-family: var(--font-cn);
  color: var(--gray-800);
  line-height: 1.7;
  background: var(--white);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--red); text-decoration: none; transition: var(--transition); }
a:hover { opacity: .85; }

/* --- Container --- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}
.container-narrow {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Section Base --- */
.section {
  padding: 80px 0;
  position: relative;
}
.section--gray { background: var(--gray-50); }
.section--red { background: linear-gradient(135deg, var(--red) 0%, var(--red-dark) 100%); color: var(--white); }
.section--navy { background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%); color: var(--white); }

.section-title {
  text-align: center;
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 48px;
  letter-spacing: 3px;
  position: relative;
}
.section-title::after {
  content: "";
  display: block;
  width: 60px;
  height: 4px;
  background: var(--red);
  margin: 16px auto 0;
  border-radius: 2px;
}
.section-title.white::after { background: var(--gold); }
.section-subtitle {
  text-align: center;
  font-size: 1.05rem;
  color: var(--gray-600);
  max-width: 700px;
  margin: -32px auto 40px;
  line-height: 1.8;
}
.section--red .section-subtitle,
.section--navy .section-subtitle { color: rgba(255,255,255,.8); margin-top: -36px; }

/* ============================================
   NAVIGATION
   ============================================ */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(255,255,255,.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(0,0,0,.06);
  transition: var(--transition);
  height: 64px;
  display: flex;
  align-items: center;
}
.navbar.scrolled {
  box-shadow: var(--shadow-sm);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  width: 100%;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--red);
  white-space: nowrap;
}
.nav-logo img { height: 40px; width: auto; max-width: 220px; }
.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
}
.nav-links a {
  color: var(--gray-800);
  font-size: 1rem;
  font-weight: 600;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: var(--transition);
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--red);
  border-bottom-color: var(--red);
}

/* Mobile Menu Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  background: none;
  border: none;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--gray-800);
  transition: var(--transition);
  border-radius: 1px;
}
.nav-toggle.active span:nth-child(1) { transform: rotate(45deg) translateY(7px); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: rotate(-45deg) translateY(-7px); }

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(135deg, var(--red-deep) 0%, var(--red) 30%, var(--red-dark) 70%, var(--navy) 100%);
  color: var(--white);
  padding-top: 64px;
}

/* Red ribbon/wave effect overlay */
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 80%, rgba(212,168,83,.15) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 20%, rgba(255,255,255,.08) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 40px 24px;
  max-width: 900px;
}

.hero-slogan-top {
  font-size: 1.15rem;
  font-weight: 400;
  letter-spacing: 6px;
  opacity: .9;
  margin-bottom: 24px;
}

.hero-logo-img {
  width: 110px;
  height: 110px;
  margin: 0 auto 28px;
  border-radius: 50%;
  background: rgba(255,255,255,.15);
  padding: 6px;
  backdrop-filter: blur(4px);
}

.hero-main-title {
  font-size: 3.2rem;
  font-weight: 900;
  letter-spacing: 4px;
  line-height: 1.3;
  margin-bottom: 12px;
  text-shadow: 0 2px 20px rgba(0,0,0,.2);
}
.hero-main-title .year {
  font-size: 4rem;
  display: inline-block;
  margin-right: 8px;
  font-style: italic;
  background: linear-gradient(180deg, #FFF 0%, var(--gold-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-hosts {
  margin: 32px auto 0;
  font-size: .95rem;
  line-height: 2;
  opacity: .88;
  max-width: 650px;
}
.hero-hosts strong { color: var(--gold); }

.hero-slogans {
  margin-top: 44px;
  display: flex;
  gap: 40px;
  justify-content: center;
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: 4px;
}
.hero-slogans em {
  font-style: normal;
  font-size: 2rem;
  color: var(--gold);
  margin: 0 6px;
}

.hero-date-location {
  margin-top: 52px;
  font-size: 1.2rem;
  letter-spacing: 3px;
  opacity: .95;
  display: inline-flex;
  align-items: center;
  gap: 20px;
  padding: 14px 36px;
  border: 1px solid rgba(255,255,255,.25);
  border-radius: 999px;
  background: rgba(255,255,255,.06);
  backdrop-filter: blur(4px);
}

/* ============================================
   HERO SECTION
   ============================================ */
.about-quote-block {
  background: linear-gradient(135deg, var(--red) 0%, var(--red-dark) 100%);
  border-radius: var(--radius-xl);
  padding: 48px 56px;
  color: var(--white);
  margin-bottom: 48px;
  position: relative;
  box-shadow: var(--shadow-red);
}
.about-quote-block::before {
  content: """;
  position: absolute;
  top: 16px; left: 28px;
  font-size: 80px;
  font-family: Georgia, serif;
  color: rgba(255,255,255,.18);
  line-height: 1;
}
.about-quote-text {
  font-size: 1.2rem;
  line-height: 2;
  font-weight: 500;
  position: relative;
  z-index: 1;
}
.about-quote-source {
  text-align: right;
  margin-top: 20px;
  font-size: .95rem;
  opacity: .8;
  letter-spacing: 2px;
}

.about-body {
  font-size: 1.05rem;
  line-height: 2.1;
  color: var(--gray-600);
  text-align: justify;
}

/* ============================================
   ORGANIZERS / 组织机构
   ============================================ */
.org-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: start;
  margin-bottom: 56px;
  background: var(--white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: var(--transition);
}
.org-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.org-card:nth-child(even) { direction: rtl; }
.org-card:nth-child(even) > * { direction: ltr; }
.org-info { padding: 40px 36px; }
.org-name {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--red);
  margin-bottom: 16px;
  border-left: 4px solid var(--red);
  padding-left: 14px;
}
.org-desc {
  font-size: .95rem;
  color: var(--gray-600);
  line-height: 1.95;
  text-align: justify;
}
.org-image {
  width: 100%;
  min-height: 260px;
  object-fit: cover;
}

/* Executor section */
.executor-box {
  background: var(--navy);
  color: var(--white);
  border-radius: var(--radius-lg);
  padding: 36px 40px;
  margin-top: 24px;
}
.executor-label {
  color: var(--gold);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 2px;
  margin-bottom: 12px;
}
.executor-name {
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.8;
}

/* ============================================
   GUESTS / 拟邀请嘉宾
   ============================================ */
#guests {
  overflow: hidden;
}
#guests::before {
  content: "";
  position: absolute;
  top: 150px;
  right: 10%;
  width: 100%;
  height: 100%;
  background: url("../images/p04_19.png") no-repeat top right;
  background-size: auto;
  z-index: 0;
  opacity: .55;
}
#guests .container {
  position: relative;
  z-index: 1;
}
.guest-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}
.guest-card--placeholder {
  visibility: hidden;
}
.guest-card {
  text-align: center;
  background: var(--white);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border: 1px solid var(--gray-200);
}
.guest-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
  border-color: var(--red);
}
.guest-avatar {
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
  object-position: top center;
  background: var(--gray-100);
}
.guest-name {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 14px 0 6px;
  color: var(--gray-900);
}
.guest-title {
  font-size: .82rem;
  color: var(--gray-600);
  line-height: 1.6;
  padding: 0 14px 20px;
}

/* ============================================
   AGENDA / 拟定议程
   ============================================ */
.agenda-wrapper {
  position: relative;
}
.agenda-bg-img {
  position: absolute;
  inset: 0;
  object-fit: cover;
  opacity: .07;
  pointer-events: none;
}
.agenda-day {
  margin-bottom: 48px;
  position: relative;
  z-index: 1;
}
.agenda-day-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
}
.agenda-day-icon {
  width: 48px;
  height: 48px;
  background: var(--red);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.agenda-day-icon::after {
  content: "\25B6";
  color: var(--white);
  font-size: 18px;
}
.agenda-day-title {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--red);
}

.agenda-session {
  background: var(--white);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin-bottom: 16px;
  box-shadow: var(--shadow-sm);
  border-left: 4px solid var(--red-dark);
  transition: var(--transition);
}
.agenda-session:hover { box-shadow: var(--shadow-md); }
.agenda-session-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 10px;
}
.agenda-session-list {
  list-style: none;
  padding-left: 0;
}
.agenda-session-list li {
  padding: 6px 0 6px 22px;
  position: relative;
  font-size: .94rem;
  color: var(--gray-600);
  line-height: 1.7;
}
.agenda-session-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 15px;
  width: 8px;
  height: 8px;
  background: var(--red);
  border-radius: 50%;
  opacity: .6;
}

/* ============================================
   FORMATS / 大会形式
   ============================================ */
.format-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}
.format-card {
  background: var(--white);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  cursor: default;
}
.format-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}
.format-card-img {
  width: 100%;
  aspect-ratio: 16/10;
  object-fit: cover;
}
.format-card-name {
  text-align: center;
  padding: 14px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--gray-800);
}

/* ============================================
   VALUE / 参会方式及价值
   ============================================ */
.value-intro {
  font-size: 1.05rem;
  line-height: 2;
  color: rgba(255,255,255,.88);
  text-align: justify;
  margin-bottom: 48px;
  max-width: 850px;
  margin-left: auto;
  margin-right: auto;
}

.value-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
  margin-bottom: 40px;
}
.value-item {
  display: flex;
  gap: 18px;
  background: rgba(255,255,255,.08);
  border: 1px solid rgba(255,255,255,.12);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  backdrop-filter: blur(4px);
  transition: var(--transition);
}
.value-item:hover {
  background: rgba(255,255,255,.14);
  transform: translateY(-2px);
  border-color: var(--gold);
}
.value-icon {
  flex-shrink: 0;
  width: 46px;
  height: 46px;
  background: var(--red);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: var(--white);
}
.value-content h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 6px;
}
.value-content p {
  font-size: .88rem;
  color: rgba(255,255,255,.75);
  line-height: 1.75;
}

.value-gallery {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 32px;
}
.value-gallery img {
  object-fit: contain;
}

/* ============================================
   PAST EVENTS / 往届活动
   ============================================ */
.event-list { display: flex; flex-direction: column; gap: 40px; }
.event-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  align-items: stretch;
  background: var(--white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: var(--transition);
}
.event-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-2px); }
.event-card:nth-child(even) { direction: rtl; }
.event-card:nth-child(even) > * { direction: ltr; }

.event-images {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  padding: 24px;
}
.event-images img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: var(--radius-sm);
}
.event-info {
  padding: 40px 36px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.event-tag {
  display: inline-block;
  background: var(--red);
  color: var(--white);
  font-size: .78rem;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: 999px;
  letter-spacing: 1px;
  margin-bottom: 12px;
}
.event-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 8px;
}
.event-meta {
  font-size: .92rem;
  color: var(--gray-600);
  line-height: 1.7;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background: linear-gradient(135deg, var(--red) 0%, var(--red-dark) 100%);
  color: rgba(255,255,255,.8);
  padding: 56px 0 32px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 48px;
  align-items: start;
}
.footer-brand {
  text-align: center;
}
.footer-logo {
  width: 90px;
  height: 90px;
  border-radius: 50%;
  margin: 0 auto 16px;
  background: rgba(255,255,255,.08);
  padding: 4px;
}
.footer-org-name {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 2px;
  line-height: 1.6;
}
.footer-contact dt {
  font-weight: 700;
  color: var(--white);
  margin-top: 16px;
  font-size: .95rem;
}
.footer-contact dd {
  font-size: .92rem;
  line-height: 1.8;
  margin-left: 0;
}
.footer-bottom {
  text-align: center;
  padding-top: 28px;
  margin-top: 36px;
  border-top: 1px solid rgba(255,255,255,.1);
  font-size: .82rem;
  opacity: .5;
}

/* ============================================
   RESPONSIVE - Tablet (<1024px)
   ============================================ */
@media (max-width: 1024px) {
  .hero-main-title { font-size: 2.4rem; }
  .hero-main-title .year { font-size: 3rem; }
  .org-card { grid-template-columns: 1fr; }
  .org-card:nth-child(even) { direction: ltr; }
  .event-card { grid-template-columns: 280px 1fr; gap: 24px; }
  .value-gallery { grid-template-columns: repeat(2, 1fr); }
}

/* ============================================
   RESPONSIVE - Mobile (<768px)
   ============================================ */
@media (max-width: 768px) {
  :root { font-size: 15px; }
  .section { padding: 56px 0; }
  .section-title { font-size: 1.55rem; margin-bottom: 32px; }

  /* Nav mobile */
  .nav-links {
    display: none;
    position: fixed;
    top: 64px; left: 0; right: 0;
    bottom: 0;
    background: rgba(255,255,255,.98);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 20px;
    z-index: 999;
  }
  .nav-links.active { display: flex; }
  .nav-links a { font-size: 1.1rem; }
  .nav-toggle { display: flex; }

  /* Hero mobile */
  .hero { min-height: 100svh; padding-top: 64px; }
  .hero-main-title { font-size: 1.7rem; }
  .hero-main-title .year { font-size: 2.2rem; }
  .hero-slogan-top { font-size: .9rem; letter-spacing: 3px; }
  .hero-slogans {
    flex-direction: column;
    gap: 16px;
    font-size: 1.2rem;
  }
  .hero-slogans em { font-size: 1.4rem; }
  .hero-date-location {
    flex-direction: column;
  font-size: 1.2rem;
    padding: 12px 24px;
  }
  .scroll-hint { display: none; }

  /* About */
  .about-quote-block { padding: 28px 24px; }
  .about-quote-text { font-size: 1.02rem; line-height: 1.9; }

  /* Organizers */
  .org-info { padding: 24px 20px; }
  .org-name { font-size: 1.15rem; }

  /* Guests */
  .guest-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }
  .guest-card--placeholder { display: none; }
  .guest-title { font-size: .76rem; }

  /* Agenda */
  .agenda-session { padding: 18px 20px; }

  /* Formats */
  .format-grid { grid-template-columns: repeat(2, 1fr); gap: 14px; }

  /* Value */
  .value-grid { grid-template-columns: 1fr; }
  .value-gallery { grid-template-columns: 1fr; }

  /* Past Events */
  .event-card {
    grid-template-columns: 1fr;
    direction: ltr !important;
  }
  .event-info { padding: 20px; }

  /* Footer */
  .footer-inner { grid-template-columns: 1fr; text-align: center; }
  .footer-contact { text-align: left; }
}

/* ============================================
   ANIMATIONS (scroll reveal)
   ============================================ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal-delay-1 { transition-delay: .1s; }
.reveal-delay-2 { transition-delay: .2s; }
.reveal-delay-3 { transition-delay: .3s; }
.reveal-delay-4 { transition-delay: .4s; }

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 44px;
  height: 44px;
  background: var(--red);
  color: var(--white);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 99;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  box-shadow: var(--shadow-red);
}
.back-to-top.show { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-3px); background: var(--red-dark); }