/* 
 * 一生二 (Yi Sheng Er) Official Website Core Stylesheet
 * Author: Senior Frontend Architect
 * Design Tokens: Modern tech-blue, soft magenta, clean typography, glassmorphic elements, smooth micro-interactions.
 */

@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800&family=Noto+Sans+SC:wght@300;400;500;700;900&display=swap');

/* ==========================================
   1. Design System & CSS Variables
   ========================================== */
:root {
  /* Brand Colors */
  --primary-hue: 209;
  --primary: hsl(var(--primary-hue), 100%, 54%); /* #1890FF */
  --primary-light: hsl(var(--primary-hue), 100%, 96%);
  --primary-dark: hsl(var(--primary-hue), 100%, 40%);
  --primary-rgb: 24, 144, 255;

  --accent-hue: 347;
  --accent: hsl(var(--accent-hue), 90%, 61%); /* #f44066 */
  --accent-hover: hsl(var(--accent-hue), 90%, 50%);
  --accent-rgb: 244, 64, 102;

  /* Neutrals */
  --bg-body: #f7f9fc;
  --bg-card: #ffffff;
  --bg-dark: #0b0b16;
  --bg-dark-card: #15152b;
  --text-main: #2d3142;
  --text-muted: #6b7280;
  --text-light: #ffffff;
  --border-light: rgba(228, 231, 237, 0.7);

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 24px rgba(24, 144, 255, 0.06);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.08);
  --shadow-glass: 0 8px 32px 0 rgba(31, 38, 135, 0.07);

  /* Borders & Radius */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  --transition-slow: 0.5s cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* ==========================================
   2. Reset & Global Styles
   ========================================== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px; /* Base for rem */
}

body {
  background-color: var(--bg-body);
  color: var(--text-main);
  font-family: 'Outfit', 'Noto Sans SC', "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

ul {
  list-style: none;
}

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

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

/* Grid & Layout Containers */
.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

.section-padding {
  padding: 100px 0;
}

@media (max-width: 768px) {
  .section-padding {
    padding: 60px 0;
  }
}

/* Common Section Headers */
.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 60px auto;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--bg-dark);
  position: relative;
  display: inline-block;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: var(--radius-full);
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
}

/* Custom Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-normal);
  border: 1px solid transparent;
  outline: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), #0076e5);
  color: var(--text-light);
  box-shadow: 0 4px 14px rgba(24, 144, 255, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(24, 144, 255, 0.6);
}

.btn-accent {
  background: linear-gradient(135deg, var(--accent), var(--accent-hover));
  color: var(--text-light);
  box-shadow: 0 4px 14px rgba(244, 64, 102, 0.4);
}

.btn-accent:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(244, 64, 102, 0.6);
}

.btn-outline {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.3);
  color: var(--text-light);
}

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

.btn-outline-dark {
  background: transparent;
  border-color: var(--primary);
  color: var(--primary);
}

.btn-outline-dark:hover {
  background: var(--primary-light);
  transform: translateY(-2px);
}

/* ==========================================
   3. Header & Navigation (Glassmorphic)
   ========================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 80px;
  z-index: 1000;
  display: flex;
  align-items: center;
  transition: var(--transition-normal);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

/* Header scrolled state */
.site-header.scrolled {
  height: 70px;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid rgba(228, 231, 237, 0.7);
  box-shadow: var(--shadow-sm);
  color: var(--text-main);
}

/* When not scrolled, text is light because the banner is dark */
.site-header:not(.scrolled) {
  background: transparent;
  color: var(--text-light);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-img {
  width: 38px;
  height: 38px;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.logo-text {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, #ffffff, #cce6ff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  transition: var(--transition-normal);
}

.scrolled .logo-text {
  background: linear-gradient(135deg, var(--bg-dark), var(--primary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Navigation Menu */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 40px;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  position: relative;
  padding: 8px 0;
  opacity: 0.9;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--primary);
  transition: var(--transition-fast);
  border-radius: var(--radius-full);
}

.site-header:not(.scrolled) .nav-link::after {
  background-color: var(--text-light);
}

.nav-link:hover,
.nav-link.active {
  opacity: 1;
}

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

/* Hamburger & Mobile Nav */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 24px;
  height: 18px;
  background: transparent;
  border: none;
  cursor: pointer;
  outline: none;
  z-index: 1001;
}

.menu-toggle span {
  width: 100%;
  height: 2px;
  background-color: currentColor;
  transition: var(--transition-fast);
}

@media (max-width: 992px) {
  .menu-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--bg-dark-card);
    flex-direction: column;
    align-items: flex-start;
    padding: 100px 40px 40px 40px;
    gap: 30px;
    box-shadow: var(--shadow-lg);
    transition: var(--transition-slow);
    color: var(--text-light);
  }

  .nav-menu.active {
    right: 0;
  }

  .nav-menu .nav-link {
    font-size: 1.1rem;
    width: 100%;
  }

  .nav-menu .btn-nav {
    width: 100%;
    margin-top: 20px;
  }

  .menu-toggle.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
  }

  .menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }

  .menu-toggle.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
  }
}

/* ==========================================
   4. Hero / Banner Section
   ========================================== */
.hero-section {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background-color: var(--bg-dark);
  background-image: url('../img/banner.png');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  color: var(--text-light);
  padding: 140px 0 80px 0;
  overflow: hidden;
}

/* Dark overlay for better text contrast */
.hero-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 80% 20%, rgba(24, 144, 255, 0.1), rgba(0, 0, 0, 0.8) 70%);
  z-index: 1;
}

.hero-section .container {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  align-items: center;
  gap: 60px;
}

.hero-content {
  max-width: 720px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  background: rgba(24, 144, 255, 0.15);
  border: 1px solid rgba(24, 144, 255, 0.3);
  font-size: 0.85rem;
  font-weight: 600;
  color: #cce6ff;
  margin-bottom: 24px;
  letter-spacing: 0.5px;
  backdrop-filter: blur(5px);
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -1px;
  margin-bottom: 24px;
}

.hero-title span {
  background: linear-gradient(135deg, #ffffff, #66b1ff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-description {
  font-size: 1.15rem;
  line-height: 1.7;
  color: #b0c4de;
  margin-bottom: 40px;
}

.hero-actions {
  display: flex;
  gap: 16px;
}

/* Glassmorphic info panel on the right of Hero */
.hero-panel {
  background: rgba(255, 255, 255, 0.04);
  backdrop-filter: blur(12px) saturate(180%);
  -webkit-backdrop-filter: blur(12px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-glass);
}

.panel-title {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 24px;
  position: relative;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.panel-title::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 40px;
  height: 2px;
  background: var(--primary);
}

.panel-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.panel-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.panel-icon-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: rgba(24, 144, 255, 0.2);
  color: var(--primary-light);
  flex-shrink: 0;
}

.panel-item-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.panel-item-desc {
  font-size: 0.85rem;
  color: #b0c4de;
}

@media (max-width: 992px) {
  .hero-section .container {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  
  .hero-title {
    font-size: 2.75rem;
  }

  .hero-section {
    padding: 120px 0 60px 0;
  }
}

@media (max-width: 576px) {
  .hero-title {
    font-size: 2.25rem;
  }

  .hero-actions {
    flex-direction: column;
    gap: 12px;
  }

  .hero-actions .btn {
    width: 100%;
  }
}

/* ==========================================
   5. Features / Core Advantages Section
   ========================================== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 40px 30px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition-normal);
}

.feature-icon-box {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-md);
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  font-size: 1.5rem;
  margin-bottom: 24px;
  transition: var(--transition-normal);
}

.feature-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--bg-dark);
}

.feature-card-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* Hover interactions */
.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(24, 144, 255, 0.2);
}

.feature-card:hover::before {
  transform: scaleX(1);
}

.feature-card:hover .feature-icon-box {
  background: var(--primary);
  color: var(--text-light);
  transform: scale(1.05) rotate(5deg);
}

@media (max-width: 1200px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .features-grid {
    grid-template-columns: 1fr;
  }
}

/* ==========================================
   6. About Us Section (Dynamic tabbed content)
   ========================================== */
.about-section {
  background: #ffffff;
  position: relative;
}

.about-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-image-wrap {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.about-img {
  width: 100%;
  object-fit: cover;
  transition: var(--transition-slow);
}

.about-image-wrap:hover .about-img {
  transform: scale(1.03);
}

.about-content-header {
  margin-bottom: 24px;
}

.about-tag {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--primary);
  letter-spacing: 1.5px;
  margin-bottom: 12px;
  display: block;
}

.about-main-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--bg-dark);
  margin-bottom: 20px;
}

.about-description {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.7;
  margin-bottom: 30px;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  border-top: 1px solid var(--border-light);
  padding-top: 30px;
}

.stat-item {
  text-align: left;
}

.stat-num {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 4px;
}

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

@media (max-width: 992px) {
  .about-layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

/* ==========================================
   7. Company Culture Section
   ========================================== */
.culture-section {
  background: var(--bg-body);
}

.culture-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.culture-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 30px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-normal);
  text-align: center;
}

.culture-icon-wrap {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: rgba(244, 64, 102, 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  font-size: 1.25rem;
  margin: 0 auto 20px auto;
  transition: var(--transition-normal);
}

.culture-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--bg-dark);
  margin-bottom: 12px;
}

.culture-card-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.culture-card:hover {
  transform: scale(1.03);
  box-shadow: var(--shadow-lg);
  border-color: rgba(244, 64, 102, 0.2);
}

.culture-card:hover .culture-icon-wrap {
  background: var(--accent);
  color: var(--text-light);
}

@media (max-width: 1200px) {
  .culture-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .culture-grid {
    grid-template-columns: 1fr;
  }
}

/* ==========================================
   8. Future / Prospect Planning Section
   ========================================== */
.prospect-section {
  background: #ffffff;
}

.prospect-layout {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 60px;
  align-items: center;
}

.prospect-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--bg-dark);
  margin-bottom: 24px;
}

.prospect-list {
  display: flex;
  flex-direction: column;
  gap: 30px;
}

.prospect-item {
  display: flex;
  gap: 20px;
}

.prospect-num-box {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--primary-light);
  color: var(--primary);
  font-size: 1.15rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.prospect-header {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--bg-dark);
  margin-bottom: 6px;
}

.prospect-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.65;
}

@media (max-width: 992px) {
  .prospect-layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

/* ==========================================
   9. Contact & Support Section (Glassmorphic)
   ========================================== */
.contact-section {
  background: var(--bg-dark);
  background-image: radial-gradient(circle at 10% 20%, rgba(244, 64, 102, 0.08), transparent 40%),
                    radial-gradient(circle at 90% 80%, rgba(24, 144, 255, 0.08), transparent 40%);
  color: var(--text-light);
}

.contact-layout {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 60px;
  align-items: center;
}

.contact-info-title {
  font-size: 2.25rem;
  font-weight: 800;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #ffffff, #66b1ff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.contact-info-desc {
  font-size: 1.1rem;
  color: #b0c4de;
  margin-bottom: 40px;
  max-width: 540px;
}

.contact-cards-wrap {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 40px;
}

.contact-detail-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-md);
  padding: 24px;
}

.contact-card-icon {
  font-size: 1.35rem;
  color: var(--primary);
  margin-bottom: 12px;
}

.contact-card-label {
  font-size: 0.85rem;
  color: #8fa0b5;
  margin-bottom: 4px;
}

.contact-card-value {
  font-size: 1rem;
  font-weight: 600;
}

/* Support QR card right side */
.support-qr-box {
  background: rgba(255, 255, 255, 0.04);
  backdrop-filter: blur(12px) saturate(180%);
  -webkit-backdrop-filter: blur(12px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-lg);
  padding: 40px;
  text-align: center;
  box-shadow: var(--shadow-glass);
}

.support-qr-title {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.support-qr-subtitle {
  font-size: 0.9rem;
  color: #b0c4de;
  margin-bottom: 24px;
}

.qr-img-wrapper {
  background: #ffffff;
  padding: 16px;
  border-radius: var(--radius-md);
  display: inline-block;
  margin-bottom: 24px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.qr-image {
  width: 180px;
  height: 180px;
  object-fit: cover;
}

.support-prompt {
  font-size: 0.85rem;
  color: #8fa0b5;
}

@media (max-width: 992px) {
  .contact-layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

@media (max-width: 576px) {
  .contact-cards-wrap {
    grid-template-columns: 1fr;
  }
}

/* ==========================================
   10. Footer Section
   ========================================== */
.site-footer {
  background: #06060c;
  color: #8fa0b5;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding: 60px 0 30px 0;
}

.footer-top {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}

.footer-brand-desc {
  font-size: 0.9rem;
  line-height: 1.6;
  margin-top: 16px;
}

.footer-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-light);
  margin-bottom: 20px;
  position: relative;
}

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

.footer-link {
  font-size: 0.9rem;
  transition: var(--transition-fast);
}

.footer-link:hover {
  color: var(--text-light);
  transform: translateX(4px);
}

/* Footer Bottom */
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 30px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 0.85rem;
}

.footer-copy {
  color: #6b788a;
}

.footer-icp {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #6b788a;
  transition: var(--transition-fast);
}

.footer-icp:hover {
  color: var(--text-light);
}

@media (max-width: 768px) {
  .footer-top {
    grid-template-columns: 1fr;
    gap: 30px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
    justify-content: center;
  }
}

/* ==========================================
   11. Single Page Application (SPA) Switches
   ========================================== */
/* We will define two virtual view wrappers */
.view-wrapper {
  display: none; /* Hidden by default */
  width: 100%;
}

.view-wrapper.active {
  display: block; /* Shown only when active */
  animation: fadeIn 0.4s ease forwards;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}