/* ========================================
   FlowAchive 势成之 — Design System
   Dark Premium Theme
   ======================================== */

/* ── Design Tokens ── */
:root {
  /* 背景色阶 */
  --bg-deep:        #0D0F12;
  --bg-card:        #161920;
  --bg-elevated:    #1C2028;
  --bg-input:       #1E222A;

  /* 金色强调 */
  --gold:           #D4AF37;
  --gold-light:     #E8D48B;
  --gold-dim:       #A68B2A;

  /* 文本色阶 */
  --text-primary:   #E8E8E8;
  --text-secondary: #9CA3AF;
  --text-muted:     #6B7280;
  --text-heading:   #FFFFFF;
  --text-gold:      #E8D48B;

  /* 边框与分割 */
  --border:         rgba(212, 175, 55, 0.12);
  --border-subtle:  rgba(255, 255, 255, 0.06);

  /* 交互态 */
  --gold-glow:      rgba(212, 175, 55, 0.25);

  /* 排版 */
  --font-serif:     'Noto Serif SC', 'Source Han Serif SC', 'STSong', Georgia, serif;
  --font-sans:      'Inter', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;

  /* 间距 */
  --space-xs:       0.5rem;
  --space-sm:       1rem;
  --space-md:       2rem;
  --space-lg:       4rem;
  --space-xl:       6rem;

  /* 圆角 */
  --radius-sm:      0.5rem;
  --radius-md:      1rem;
  --radius-lg:      1.5rem;
  --radius-pill:    3rem;

  /* 过渡 */
  --ease-out:       cubic-bezier(0.22, 1, 0.36, 1);
  --duration:       0.4s;

  /* 兼容旧变量（chat.js 引用） */
  --color-primary:  var(--gold);
  --color-secondary: var(--gold-dim);
  --color-bg:       var(--bg-deep);
  --color-text:     var(--text-primary);
  --color-text-light: var(--text-secondary);
  --transition:     all var(--duration) var(--ease-out);
}

/* ── 基础重置 ── */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-deep);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── 容器 ── */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* ========================================
   导航栏
   ======================================== */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background: transparent;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 1000;
  transition: background var(--duration) var(--ease-out),
              box-shadow var(--duration) var(--ease-out);
}

.navbar.scrolled {
  background: rgba(13, 15, 18, 0.9);
  box-shadow: 0 1px 0 var(--border);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.25rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--gold);
  text-decoration: none;
  letter-spacing: 0.02em;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.nav-logo-img {
  height: 3.2rem;
  width: auto;
}

.nav-menu {
  display: flex;
  gap: 2.5rem;
  align-items: center;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 400;
  font-size: 0.9rem;
  letter-spacing: 0.03em;
  transition: color var(--duration) var(--ease-out);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--gold);
  transition: width var(--duration) var(--ease-out);
}

.nav-link:hover,
.nav-link.active {
  color: var(--gold-light);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.nav-cta {
  background: transparent;
  color: var(--gold);
  padding: 0.6rem 1.5rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--gold);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9rem;
  letter-spacing: 0.03em;
  transition: all var(--duration) var(--ease-out);
}

.nav-cta:hover {
  background: var(--gold);
  color: var(--bg-deep);
}

/* ========================================
   Hero 区域
   ======================================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6rem 2rem 4rem;
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(ellipse 60% 50% at 50% 45%, rgba(212, 175, 55, 0.06) 0%, transparent 70%),
    var(--bg-deep);
}

.hero-layout {
  max-width: 1100px;
  width: 100%;
  display: flex;
  align-items: center;
  gap: 4rem;
}

.hero-left {
  flex: 1;
  position: relative;
  z-index: 1;
}

.hero-right {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2rem;
  padding-left: 3rem;
  border-left: 1px solid var(--border);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(30px); }
  to   { opacity: 1; transform: translateY(0); }
}

.hero-brand {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  color: var(--gold);
  letter-spacing: 0.15em;
  margin-bottom: 0.5rem;
}

.hero-tagline {
  font-size: 0.85rem;
  color: var(--text-muted);
  letter-spacing: 0.25em;
  margin-bottom: 2.5rem;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 3.8vw, 2.8rem);
  font-weight: 600;
  color: var(--text-heading);
  margin-bottom: 1.5rem;
  line-height: 1.3;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.hero-title .highlight {
  display: block;
  color: var(--gold);
  font-size: 2.4rem;
  margin-top: 1rem;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  line-height: 2;
}

.hero-cta {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1.25rem;
  margin-top: 1rem;
}

/* ── Hero 右侧引言 ── */
.hero-quote {
  margin-bottom: 0.5rem;
}

.quote-text {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  color: var(--gold-light);
  line-height: 1.8;
  letter-spacing: 0.04em;
}

.quote-source {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-top: 0.75rem;
  letter-spacing: 0.05em;
}

.hero-insight {
  position: relative;
  padding-left: 1.25rem;
}

.hero-insight::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.3rem;
  width: 2px;
  height: calc(100% - 0.6rem);
  background: var(--gold-dim);
  opacity: 0.4;
}

.hero-insight p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.9;
}

.hero-note {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ========================================
   按钮
   ======================================== */
.btn-primary {
  background: var(--gold);
  color: var(--bg-deep);
  padding: 1rem 2.5rem;
  border-radius: var(--radius-pill);
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  display: inline-block;
  transition: all var(--duration) var(--ease-out);
  border: none;
  cursor: pointer;
  letter-spacing: 0.03em;
}

.btn-primary:hover {
  background: var(--gold-light);
  transform: translateY(-3px);
  box-shadow: 0 8px 30px var(--gold-glow);
}

.btn-secondary {
  background: transparent;
  color: var(--gold);
  padding: 0.875rem 2rem;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(212, 175, 55, 0.4);
  text-decoration: none;
  font-weight: 500;
  display: inline-block;
  transition: all var(--duration) var(--ease-out);
  letter-spacing: 0.03em;
}

.btn-secondary:hover {
  background: rgba(212, 175, 55, 0.1);
  border-color: var(--gold);
}

.btn-link {
  color: var(--gold);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--duration) var(--ease-out);
}

.btn-link:hover {
  color: var(--gold-light);
}

.btn-large {
  padding: 1.25rem 3rem;
  font-size: 1.1rem;
}

/* ========================================
   Section: 概念解析区（什么是「势」？）
   ======================================== */
.concept-section {
  padding: var(--space-xl) 0;
  background: var(--bg-deep);
  position: relative;
}

.concept-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--gold), transparent);
}

.section-label {
  font-size: 0.8rem;
  color: var(--gold);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  text-align: center;
  margin-bottom: 0.75rem;
}

.section-title {
  font-family: var(--font-serif);
  font-size: 2rem;
  color: var(--text-heading);
  margin-bottom: 3.5rem;
  text-align: center;
  font-weight: 500;
  letter-spacing: 0.04em;
}

.text-center {
  text-align: center;
}

.concept-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  max-width: 1100px;
  margin: 0 auto;
}

.concept-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  transition: all var(--duration) var(--ease-out);
  position: relative;
  overflow: hidden;
}

.concept-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--gold), transparent);
  opacity: 0;
  transition: opacity var(--duration) var(--ease-out);
}

.concept-card:hover {
  transform: translateY(-6px);
  border-color: rgba(212, 175, 55, 0.25);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.3), 0 0 30px var(--gold-glow);
}

.concept-card:hover::before {
  opacity: 1;
}

.concept-card-title {
  font-family: var(--font-serif);
  font-size: 1.6rem;
  color: var(--gold);
  margin-bottom: 1.25rem;
  letter-spacing: 0.1em;
  text-align: center;
}

.concept-card-text {
  color: var(--text-secondary);
  line-height: 1.9;
  font-size: 0.95rem;
}

.concept-card-text strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* ========================================
   Section: 品牌愿景区
   ======================================== */
.vision-section {
  padding: var(--space-xl) 0;
  background:
    radial-gradient(ellipse 50% 40% at 50% 50%, rgba(212, 175, 55, 0.04) 0%, transparent 70%),
    var(--bg-deep);
  position: relative;
}

.vision-text {
  max-width: 680px;
  margin: 0 auto;
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 2.5;
  letter-spacing: 0.02em;
}

.vision-text em {
  color: var(--gold);
  font-style: normal;
}

.vision-brand {
  margin-top: 3rem;
  text-align: center;
  font-family: var(--font-serif);
  font-size: 1.3rem;
  color: var(--gold);
  letter-spacing: 0.15em;
}

/* ========================================
   微信二维码浮动
   ======================================== */
.wechat-float {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 1rem;
  border-radius: var(--radius-md);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
  text-align: center;
  z-index: 999;
}

.wechat-label {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--gold);
  margin-bottom: 0.5rem;
}

.wechat-qr {
  width: 110px;
  height: 110px;
  border-radius: var(--radius-sm);
  margin: 0.5rem auto;
}

.wechat-note {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

/* ========================================
   页脚
   ======================================== */
.footer {
  background: var(--bg-deep);
  padding: 3rem 0 1.5rem;
  border-top: 1px solid var(--border);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

.footer-logo {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--gold);
}

.footer-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

.footer-links {
  display: flex;
  gap: 2rem;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color var(--duration) var(--ease-out);
}

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

.footer-bottom {
  text-align: center;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ========================================
   Fade-in 动画（IntersectionObserver）
   ======================================== */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}

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

/* ========================================
   响应式
   ======================================== */
@media (max-width: 768px) {
  .hero-title .highlight {
    font-size: 1.6rem;
  }

  .hero-layout {
    flex-direction: column;
    gap: 3rem;
  }

  .hero-right {
    padding-left: 0;
    border-left: none;
    border-top: 1px solid var(--border);
    padding-top: 2.5rem;
  }

  .hero-subtitle {
    font-size: 0.95rem;
  }

  .nav-link {
    display: none;
  }

  .concept-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .concept-card {
    padding: 2rem 1.5rem;
  }

  .vision-text {
    font-size: 0.95rem;
    line-height: 2.2;
    padding: 0 1rem;
  }

  .section-title {
    font-size: 1.5rem;
  }

  .footer-content {
    flex-direction: column;
    gap: 1.5rem;
    text-align: center;
  }

  .wechat-float {
    bottom: 1rem;
    right: 1rem;
    padding: 0.75rem;
  }

  .wechat-qr {
    width: 90px;
    height: 90px;
  }
}

@media (max-width: 480px) {
  .hero-title .highlight {
    font-size: 1.3rem;
  }

  .container {
    padding: 0 1.25rem;
  }
}