/* ============================================================
   淇睿通 QIRUITONG — 全局设计系统 v3.0
   设计理念：低调奢华 · 克制内敛 · 以质取胜
   移动优先 · 滚动驱动动画 · Apple风格
   ============================================================ */

/* ========== CSS Variables ========== */
:root {
  --color-black: #080808;
  --color-off-black: #141414;
  --color-dark: #222;
  --color-charcoal: #333;
  --color-white: #fafaf9;
  --color-off-white: #f5f5f3;
  --color-cream: #eeedeb;
  --color-border: #e2e0dc;
  --color-border-light: #eeece9;
  --color-accent: #2563eb;
  --color-accent-subtle: #3b82f6;
  --color-accent-muted: rgba(37, 99, 235, 0.05);
  --color-accent-glow: rgba(37, 99, 235, 0.2);
  --color-gold: #c9a94e;
  --color-gold-light: #e0c872;
  --text-primary: #181818;
  --text-secondary: #555;
  --text-tertiary: #888;
  --text-inverse: #f5f5f3;
  --text-inverse-secondary: rgba(245, 245, 243, 0.58);
  --text-inverse-tertiary: rgba(245, 245, 243, 0.32);
  --font-sans: 'Inter', 'SF Pro Display', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Cascadia Code', monospace;
  --section-padding: 128px;
  --section-padding-mobile: 72px;
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);
  --ease-in-out-sine: cubic-bezier(0.37, 0, 0.63, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration-fast: 180ms;
  --duration-normal: 400ms;
  --duration-slow: 700ms;
  --duration-xslow: 1000ms;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 18px;
  --radius-xl: 28px;
  --radius-full: 9999px;
  --max-width: 1240px;
  --header-height: 72px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -webkit-overflow-scrolling: touch;
  scroll-padding-top: var(--header-height);
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-white);
  color: var(--text-primary);
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  letter-spacing: -0.008em;
}

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

ul, ol { list-style: none; }

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

button {
  cursor: pointer;
  border: none;
  outline: none;
  font-family: inherit;
  background: none;
  -webkit-tap-highlight-color: transparent;
}

input, textarea, select {
  font-family: inherit;
  outline: none;
  border: none;
}

::selection {
  background: rgba(37, 99, 235, 0.14);
  color: var(--text-primary);
}

/* ========== Skip Link (无障碍) ========== */
.skip-link {
  position: absolute;
  top: -100px;
  left: 8px;
  z-index: 10000;
  background: var(--color-black);
  color: var(--color-white);
  padding: 10px 20px;
  border-radius: 0 0 8px 8px;
  font-size: 14px;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0;
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* ========== Focus Visible (键盘聚焦) ========== */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 4px;
}

button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* ========== Container ========== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 48px;
}

/* ========== Section ========== */
.section {
  padding: var(--section-padding) 0;
  position: relative;
}

.section--dark {
  background: var(--color-black);
  color: var(--text-inverse);
}

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

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

.section__label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 4px;
  color: var(--color-accent);
  margin-bottom: 20px;
}

.section__label::before {
  content: '';
  width: 28px;
  height: 1px;
  background: var(--color-accent);
  opacity: 0.5;
}

.section__title {
  font-size: clamp(2.2rem, 4.5vw, 3.2rem);
  font-weight: 280;
  color: var(--text-primary);
  letter-spacing: -0.025em;
  line-height: 1.12;
  margin-bottom: 24px;
}

.section--dark .section__title {
  color: var(--text-inverse);
}

.section__subtitle {
  font-size: 1.08rem;
  color: var(--text-secondary);
  font-weight: 400;
  line-height: 1.75;
  max-width: 600px;
}

.section--dark .section__subtitle {
  color: var(--text-inverse-secondary);
}

.section__header {
  text-align: center;
  margin-bottom: 88px;
}

.section__header .section__subtitle {
  margin: 0 auto;
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 36px;
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  font-weight: 500;
  letter-spacing: 0.4px;
  transition: all var(--duration-normal) var(--ease-out-quart);
  position: relative;
  overflow: hidden;
  cursor: pointer;
}

.btn:hover {
  transform: translateY(-1px);
}

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

.btn--primary {
  background: var(--color-black);
  color: var(--color-white);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.btn--primary:hover {
  background: var(--color-off-black);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.14);
  transform: translateY(-2px);
}

.btn--outline {
  background: transparent;
  color: var(--color-black);
  border: 1px solid rgba(0, 0, 0, 0.12);
}

.btn--outline:hover {
  border-color: var(--color-black);
  background: rgba(0, 0, 0, 0.015);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.04);
}

.section--dark .btn--outline {
  color: var(--color-white);
  border-color: rgba(255, 255, 255, 0.15);
}

.section--dark .btn--outline:hover {
  border-color: rgba(255, 255, 255, 0.45);
  background: rgba(255, 255, 255, 0.04);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.btn--white {
  background: var(--color-white);
  color: var(--color-black);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.btn--white:hover {
  background: #e6e6e4;
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.1);
}

.btn--accent {
  background: var(--color-accent);
  color: #fff;
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.25);
}

.btn--accent:hover {
  background: var(--color-accent-subtle);
  box-shadow: 0 8px 32px rgba(37, 99, 235, 0.35);
  transform: translateY(-2px);
}

/* ========== Divider ========== */
.divider {
  width: 100%;
  height: 1px;
  background: var(--color-border);
}

.section--dark .divider {
  background: rgba(255, 255, 255, 0.06);
}

/* ========== Animations ========== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(48px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-48px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-40px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(40px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.94); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes scaleUp {
  from { opacity: 0; transform: scale(0.85); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 0 0 rgba(37, 99, 235, 0.3); }
  50% { box-shadow: 0 0 0 12px rgba(37, 99, 235, 0); }
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-8px); }
}

@keyframes float-slow {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-12px); }
}

@keyframes bounce-down {
  0%, 100% { transform: translateY(0); opacity: 0.5; }
  50% { transform: translateY(8px); opacity: 1; }
}

/* ========== 滚动入场动画系统 (Scroll Reveal v4.0 - 大动态增强版) ========== */

/* 基础 reveal - 上滑淡入 (位移+40%) */
.reveal {
  opacity: 0;
  transform: translateY(80px);
  filter: blur(2px);
  transition: opacity 0.9s var(--ease-out-expo), transform 0.9s var(--ease-out-expo), filter 0.9s var(--ease-out-expo);
  will-change: opacity, transform, filter;
}

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

/* reveal-left - 从左滑入 (位移+50%) */
.reveal-left {
  opacity: 0;
  transform: translateX(-100px);
  filter: blur(2px);
  transition: opacity 0.9s var(--ease-out-expo), transform 0.9s var(--ease-out-expo), filter 0.9s var(--ease-out-expo);
  will-change: opacity, transform, filter;
}

.reveal-left--visible {
  opacity: 1;
  transform: translateX(0);
  filter: blur(0);
}

/* reveal-right - 从右滑入 (位移+50%) */
.reveal-right {
  opacity: 0;
  transform: translateX(100px);
  filter: blur(2px);
  transition: opacity 0.9s var(--ease-out-expo), transform 0.9s var(--ease-out-expo), filter 0.9s var(--ease-out-expo);
  will-change: opacity, transform, filter;
}

.reveal-right--visible {
  opacity: 1;
  transform: translateX(0);
  filter: blur(0);
}

/* reveal-scale - 缩放弹入 (更夸张) */
.reveal-scale {
  opacity: 0;
  transform: scale(0.78) translateY(30px);
  filter: blur(3px);
  transition: opacity 0.85s var(--ease-spring), transform 0.85s var(--ease-spring), filter 0.85s var(--ease-spring);
  will-change: opacity, transform, filter;
}

.reveal-scale--visible {
  opacity: 1;
  transform: scale(1) translateY(0);
  filter: blur(0);
}

/* reveal-rotate - 3D旋转淡入 (角度+50%) */
.reveal-rotate {
  opacity: 0;
  transform: rotateY(25deg) translateZ(-40px) scale(0.9);
  transition: opacity 1s var(--ease-out-expo), transform 1s var(--ease-out-expo);
  will-change: opacity, transform;
}

.reveal-rotate--visible {
  opacity: 1;
  transform: rotateY(0) translateZ(0) scale(1);
}

/* reveal-blur - 纯模糊渐显 */
.reveal-blur {
  opacity: 0;
  filter: blur(12px);
  transform: scale(0.95);
  transition: opacity 0.8s var(--ease-out-expo), filter 0.8s var(--ease-out-expo), transform 0.8s var(--ease-out-expo);
  will-change: opacity, filter, transform;
}

.reveal-blur--visible {
  opacity: 1;
  filter: blur(0);
  transform: scale(1);
}

/* reveal-bounce - 弹跳入场 */
.reveal-bounce {
  opacity: 0;
  transform: translateY(60px) scale(0.85);
  transition: opacity 0.5s var(--ease-out-quart), transform 0.7s cubic-bezier(0.34, 1.56, 0.64, 1);
  will-change: opacity, transform;
}

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

/* ========== 交错子元素动画 (Stagger - 增强版) ========== */
.reveal-stagger > * {
  opacity: 0;
  transform: translateY(70px) scale(0.92);
  filter: blur(3px);
  transition: opacity 0.75s var(--ease-out-expo), transform 0.85s var(--ease-spring), filter 0.75s var(--ease-out-expo);
  will-change: opacity, transform, filter;
}

.reveal-stagger--visible > *:nth-child(1) { transition-delay: 0ms;  opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(2) { transition-delay: 90ms;  opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(3) { transition-delay: 180ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(4) { transition-delay: 270ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(5) { transition-delay: 360ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(6) { transition-delay: 450ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(7) { transition-delay: 540ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(8) { transition-delay: 630ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(9) { transition-delay: 720ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(10){ transition-delay: 810ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(11){ transition-delay: 900ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
.reveal-stagger--visible > *:nth-child(12){ transition-delay: 990ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }

/* ========== 视差滚动层 ========== */
.parallax-slow {
  transform: translateY(0);
  transition: transform 0.1s linear;
  will-change: transform;
}

.parallax-fast {
  transform: translateY(0);
  transition: transform 0.05s linear;
  will-change: transform;
}

/* ========== 滚动进度条 ========== */
.scroll-progress {
  position: fixed;
  top: 0; left: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-subtle), #8b5cf6);
  z-index: 9999;
  width: 0%;
  transition: width 0.1s linear;
  border-radius: 0 2px 2px 0;
}

/* ========== 返回顶部按钮 ========== */
.back-to-top {
  position: fixed;
  bottom: 32px; right: 24px;
  z-index: 900;
  width: 46px; height: 46px;
  border-radius: 50%;
  background: var(--color-black);
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.18);
  opacity: 0;
  transform: translateY(20px) scale(0.85);
  transition: all 0.45s var(--ease-spring);
  pointer-events: none;
  border: none;
  font-size: 1.1rem;
}

.back-to-top--visible {
  opacity: 1;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.back-to-top:active {
  transform: scale(0.9);
}

/* ========== 移动端触摸波纹 ========== */
@media (hover: none) and (pointer: coarse) {
  .ripple {
    position: relative;
    overflow: hidden;
  }

  .ripple::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0);
    transition: background 0.3s ease;
    pointer-events: none;
  }

  .ripple:active::after {
    background: rgba(0, 0, 0, 0.04);
  }
}

/* ========== Page Header ========== */
.page-header {
  padding-top: calc(var(--header-height) + 88px);
  padding-bottom: 52px;
  text-align: center;
  background: linear-gradient(180deg, var(--color-off-white) 0%, var(--color-white) 100%);
  position: relative;
  overflow: hidden;
}

.page-header::after {
  content: '';
  position: absolute;
  bottom: 0; left: 50%; transform: translateX(-50%);
  width: 80px; height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-accent), transparent);
  opacity: 0.4;
  border-radius: 1px;
  animation: pageHeaderLine 0.8s var(--ease-out-expo) 0.4s both;
}

@keyframes pageHeaderLine {
  from { width: 0; opacity: 0; }
  to   { width: 80px; opacity: 0.4; }
}

.page-header__title {
  font-size: clamp(2.2rem, 4.5vw, 3rem);
  font-weight: 280;
  color: var(--text-primary);
  letter-spacing: -0.025em;
  margin-bottom: 14px;
  animation: fadeSlideUp 0.7s var(--ease-out-expo) 0.1s both;
}

.page-header__subtitle {
  font-size: 1.02rem;
  color: var(--text-secondary);
  font-weight: 400;
  animation: fadeSlideUp 0.7s var(--ease-out-expo) 0.25s both;
}

/* ========== Scrollbar ========== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(0, 0, 0, 0.1); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(0, 0, 0, 0.2); }

/* ========== Badge ========== */
.badge-hot {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  font-size: 0.7rem;
  font-weight: 600;
  color: #dc2626;
  background: rgba(220, 38, 38, 0.06);
  border: 1px solid rgba(220, 38, 38, 0.12);
  border-radius: var(--radius-full);
  letter-spacing: 0.5px;
}

/* ========== 移动端: 滚动动画增强 (v4.0) ========== */
@media (max-width: 768px) {
  .reveal {
    transform: translateY(64px);
    transition: opacity 0.75s var(--ease-out-expo), transform 0.75s var(--ease-spring), filter 0.75s var(--ease-out-expo);
  }

  .reveal-left {
    transform: translateX(-64px);
    transition: opacity 0.75s var(--ease-out-expo), transform 0.75s var(--ease-spring);
  }

  .reveal-right {
    transform: translateX(64px);
    transition: opacity 0.75s var(--ease-out-expo), transform 0.75s var(--ease-spring);
  }

  .reveal-scale {
    transform: scale(0.82) translateY(20px);
    transition: opacity 0.7s var(--ease-spring), transform 0.7s var(--ease-spring), filter 0.7s var(--ease-spring);
  }

  .reveal-blur {
    filter: blur(8px);
    transform: scale(0.95);
    transition: opacity 0.65s var(--ease-out-expo), filter 0.65s var(--ease-out-expo);
  }

  .reveal-stagger > * {
    transform: translateY(52px) scale(0.92);
    filter: blur(2px);
    transition: opacity 0.6s var(--ease-out-expo), transform 0.72s var(--ease-spring), filter 0.6s var(--ease-out-expo);
  }

  .reveal-stagger--visible > *:nth-child(1) { transition-delay: 0ms;  opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(2) { transition-delay: 75ms;  opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(3) { transition-delay: 150ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(4) { transition-delay: 225ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(5) { transition-delay: 300ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(6) { transition-delay: 375ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(7) { transition-delay: 450ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(8) { transition-delay: 525ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(9) { transition-delay: 600ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(10){ transition-delay: 675ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(11){ transition-delay: 750ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  .reveal-stagger--visible > *:nth-child(12){ transition-delay: 825ms; opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
}

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .container { padding: 0 20px; }
  .section { padding: var(--section-padding-mobile) 0; }
  .section__header { margin-bottom: 48px; }
  .section__title { font-size: 1.75rem; }
  .section__subtitle { font-size: 0.92rem; }
  .btn { padding: 12px 28px; font-size: 0.84rem; }
  .page-header { padding-top: calc(var(--header-height) + 48px); padding-bottom: 32px; }
  .back-to-top { bottom: 20px; right: 16px; width: 42px; height: 42px; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .section__title { font-size: 1.55rem; }
  .section__header { margin-bottom: 40px; }
}

/* ========== Reduced Motion (无障碍 - 减弱动画) ========== */
@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;
  }

  .reveal,
  .reveal-left,
  .reveal-right,
  .reveal-scale,
  .reveal-rotate,
  .reveal-blur,
  .reveal-bounce,
  .reveal-stagger > * {
    opacity: 1 !important;
    transform: none !important;
    filter: none !important;
  }

  .back-to-top,
  .scroll-progress {
    transition: none !important;
  }
}

/* ========== 高对比度模式 (无障碍) ========== */
@media (prefers-contrast: more) {
  :root {
    --color-border: #000;
    --text-secondary: #333;
    --text-tertiary: #555;
  }

  .btn--outline {
    border-width: 2px;
  }
}