/* --- RESET & BASE --- */
:root {
  --primary-color: #2563EB;
  --primary-hover: #1D4ED8;
  --text-main: #111827;
  --text-secondary: #4B5563;
  --bg-color: #f9fafb;
  --font-heading: 'Noto Sans SC', sans-serif;
}

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

body {
  font-family: var(--font-heading), -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.5;
  overflow-x: hidden;
}

button { background: none; border: none; cursor: pointer; font: inherit; padding: 0; }
a { text-decoration: none; color: inherit; }
input, textarea { font-family: inherit; }

/* --- UTILITIES --- */
.hidden { display: none !important; }
.fade-in { animation: fadeIn 0.6s cubic-bezier(0.22, 1, 0.36, 1); }
@keyframes fadeIn { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }

.container { max-width: 1200px; margin: 0 auto; padding: 0 1.5rem; }

/* --- SCROLL ANIMATIONS --- */
.reveal-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

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

/* Staggered delays for grids */
.features-grid .feature-card:nth-child(1) { transition-delay: 100ms; }
.features-grid .feature-card:nth-child(2) { transition-delay: 150ms; }
.features-grid .feature-card:nth-child(3) { transition-delay: 200ms; }
.features-grid .feature-card:nth-child(4) { transition-delay: 250ms; }
.features-grid .feature-card:nth-child(5) { transition-delay: 300ms; }
.features-grid .feature-card:nth-child(6) { transition-delay: 350ms; }
.features-grid .feature-card:nth-child(7) { transition-delay: 400ms; }
.features-grid .feature-card:nth-child(8) { transition-delay: 450ms; }
.features-grid .feature-card:nth-child(9) { transition-delay: 500ms; }

.showcase-grid .showcase-card:nth-child(1) { transition-delay: 100ms; }
.showcase-grid .showcase-card:nth-child(2) { transition-delay: 150ms; }
.showcase-grid .showcase-card:nth-child(3) { transition-delay: 200ms; }
.showcase-grid .showcase-card:nth-child(4) { transition-delay: 100ms; } /* Reset for next row visual feel */
.showcase-grid .showcase-card:nth-child(5) { transition-delay: 150ms; }
.showcase-grid .showcase-card:nth-child(6) { transition-delay: 200ms; }
.showcase-grid .showcase-card:nth-child(7) { transition-delay: 100ms; }
.showcase-grid .showcase-card:nth-child(8) { transition-delay: 150ms; }
.showcase-grid .showcase-card:nth-child(9) { transition-delay: 200ms; }


/* --- Language Dropdown (Shared Logic) --- */
.lang-selector { position: relative; }
.lang-dropdown {
  position: absolute;
  top: calc(100% + 0.5rem);
  right: 0;
  background: white;
  border: 1px solid #e5e7eb;
  border-radius: 0.75rem;
  padding: 0.5rem;
  min-width: 140px;
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  display: none;
  flex-direction: column;
  gap: 0.25rem;
  z-index: 100;
    max-height: calc(90vh - 3.5rem);
    overflow: auto;
}
.lang-dropdown.show { display: flex; animation: fadeIn 0.2s ease; }
.lang-option {
  padding: 0.5rem 1rem;
  font-size: 0.85rem;
  color: #4B5563;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}
.lang-option:hover { background-color: #F3F4F6; color: #111827; }
.lang-option.active { background-color: #EFF6FF; color: var(--primary-color); font-weight: 600; }

/* ================= LANDING PAGE STYLES ================= */
#landing-view {
  background-color: #ffffff;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Landing Header */
.landing-header {
  padding: 1.5rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: absolute;
  top: 0; left: 0; right: 0;
  z-index: 50;
}

.logo { font-weight: 400; font-size: 1.2rem; color: var(--primary-color); margin-bottom: 0; display: flex;align-items: center; gap: 6px;font-family: math, -apple-system}
.logo span { color: #111827; }

.header-actions {
  display: flex; align-items: center; gap: 0.75rem;
}

.header-btn {
  display: flex; align-items: center; gap: 0.5rem;
  color: #111827;
  padding: 0.5rem 1rem;
  border-radius: 99px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.2s;
  border: 1px solid transparent;
}
.header-btn:hover {
  background-color: #F3F4F6;
  border-color: #E5E7EB;
}

.header-login-btn {
  background: #111827; color: white; 
  padding: 0.5rem 1.2rem;
  border-radius: 99px; 
  font-size: 0.9rem; font-weight: 500; 
  transition: opacity 0.2s;
}
.header-login-btn:hover { opacity: 0.9; }

/* Hero */
.hero-section {
  display: flex;
  align-items: center;
  padding: 8rem 0 4rem;
  background: radial-gradient(circle at 50% 0%, #EFF6FF 0%, #ffffff 60%);
  overflow-x: hidden;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.hero-badge {
  display: inline-block;
  background: #EFF6FF;
  color: var(--primary-color);
  padding: 0.25rem 1rem;
  border-radius: 99px;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  border: 1px solid #DBEAFE;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  color: #111827;
  margin-bottom: 1.5rem;
  line-height: 1.1;
  letter-spacing: -0.03em;
}
@media(min-width: 768px) { .hero-title { font-size: 4rem; } }

.hero-subtitle {
  font-size: 1.125rem;
  color: #4B5563;
  margin-bottom: 3rem;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.6;
}

/* Highlight style for the subtitle call-to-action */
.subtitle-highlight {
    display: block;
    margin-top: 1.5rem;
    color: var(--text-main);
    font-weight: 600;
    font-size: 1.1rem;
}

/* Input Group */
.input-group-wrapper {
  background: white;
  padding: 0.5rem;
  border-radius: 1rem;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  display: flex;
  align-items: center;
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
  border: 1px solid #E5E7EB;
  transition: all 0.3s ease;
}
.input-group-wrapper:focus-within {
  transform: translateY(-2px);
  box-shadow: 0 25px 30px -5px rgba(37, 99, 235, 0.15);
  border-color: var(--primary-color);
}

.input-prefix {
  padding: 0 1rem;
  color: #9CA3AF;
  font-weight: 500;
  font-size: 1rem;
  display: flex;
  align-items: center;
  white-space: nowrap;
  user-select: none;
}

.main-input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 1rem;
  color: #111827;
  min-width: 0;
  background: transparent;
  padding: 0.8rem 0;
}

.cta-button {
  background-color: var(--primary-color);
  color: white;
  font-weight: 600;
  padding: 0 1.5rem;
  height: 3rem;
  border-radius: 0.75rem;
  transition: all 0.2s;
  white-space: nowrap;
  display: flex;
  align-items: center;
  justify-content: center;
}
.cta-button:hover { background-color: var(--primary-hover); transform: translateY(-1px); }

/* Features Section */
.landing-features {
  padding: 4rem 0;
  background-color: #F9FAFB;
}

.landing-section-title {
    text-align: center;
    font-size: 2rem;
    font-weight: 800;
    color: #111827;
    margin-bottom: 3rem;
    letter-spacing: -0.02em;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(1, 1fr);
  gap: 1.5rem;
}
@media(min-width: 768px) { .features-grid { grid-template-columns: repeat(3, 1fr); } }

.feature-card {
  padding: 1.5rem;
  background: #ffffff;
  border-radius: 1rem;
  border: 1px solid #f3f4f6;
  box-shadow: 0 4px 6px -1px rgba(0,0,0,0.02);
  transition: all 0.3s cubic-bezier(0.22, 1, 0.36, 1);
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  text-align: left;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 15px 30px -5px rgba(0, 0, 0, 0.08);
  border-color: #e5e7eb;
}

.feature-icon {
  width: 3rem; height: 3rem; 
  background: #EFF6FF; 
  border-radius: 0.75rem;
  display: flex; align-items: center; justify-content: center; 
  color: var(--primary-color);
  flex-shrink: 0;
  transition: all 0.3s;
  margin-bottom: 0;
}
.feature-card:hover .feature-icon {
  background: var(--primary-color);
  color: white;
}

.feature-content h3 { 
  font-size: 1.1rem; 
  font-weight: 700; 
  margin-bottom: 0.25rem;
  color: #111827;
}
.feature-content p { 
  color: #4B5563; 
  font-size: 0.9rem; 
  line-height: 1.5;
}

/* Showcase Section */
.showcase-section {
  padding: 4rem 0;
  background-color: #ffffff;
  border-top: 1px solid #f3f4f6; 
}
.showcase-title {
  text-align: center; font-size: 1.8rem; font-weight: 700; margin-bottom: 3rem; color: #111827;
}
.showcase-grid {
  display: grid; grid-template-columns: 1fr; gap: 2rem;
}
@media(min-width: 768px) { .showcase-grid { grid-template-columns: repeat(3, 1fr); } }

.showcase-card {
  border-radius: 1.5rem; 
  overflow: hidden; 
  border: 1px solid #f3f4f6;
  background: white;
  transition: all 0.3s ease; 
  cursor: pointer;
  display: flex;
  flex-direction: column;
}
.showcase-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 30px -10px rgba(0,0,0,0.08);
  border-color: #e5e7eb;
}

.showcase-banner {
  height: 7rem;
  width: 100%;
  background-size: cover;
  background-position: center;
  background-color: #eee;
}

.showcase-content {
  padding: 0 1.5rem 1.5rem;
  text-align: center;
  position: relative;
}

.showcase-avatar {
  width: 4.5rem; 
  height: 4.5rem; 
  border-radius: 50%; 
  border: 4px solid white;
  object-fit: cover;
  margin-top: -2.25rem;
  margin-bottom: 0.75rem;
  background: #fff;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.showcase-name {
    font-weight: 700;
    font-size: 1.2rem;
    color: #111827;
    margin-bottom: 0.25rem;
    overflow: hidden; /* 超出部分隐藏 */
    text-overflow: ellipsis; /* 显示省略号 */
    white-space: nowrap;
}

.showcase-tags {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 0.25rem;
}

.showcase-tag { 
  font-size: 0.75rem; 
  color: var(--primary-color); 
  font-weight: 500;
  background: #EFF6FF;
  padding: 0.2rem 0.6rem;
  border-radius: 99px;
  white-space: nowrap;
}

/* Footer (Optimized) */
.landing-footer {
  padding: 4rem 0 2rem;
  border-top: 1px solid #F3F4F6;
  background: #FFFFFF;
  color: #4B5563;
}

/* New Centered Footer Style */
.footer-content-centered {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    margin-bottom: 2rem;
}

.footer-content-centered .logo { margin-bottom: 0.5rem; }

.footer-desc { 
    font-size: 0.95rem; 
    line-height: 1.6; 
    color: #6B7280; 
    margin-bottom: 1.5rem; 
    max-width: 500px; /* Center readability */
    margin-left: auto;
    margin-right: auto;
}

.social-links { display: flex; gap: 0.75rem; justify-content: center; }
.social-icon { 
    width: 36px; height: 36px; border-radius: 50%; background: #F3F4F6; color: #4B5563;
    display: flex; align-items: center; justify-content: center; transition: all 0.2s;
}
.social-icon:hover { background: var(--primary-color); color: white; transform: translateY(-2px); }

.footer-bottom {
    border-top: 1px solid #F3F4F6;
    padding-top: 2rem;
    text-align: center;
    font-size: 0.85rem;
    color: #9CA3AF;
}

/* ================= AUTH PAGES (LOGIN / REGISTER) ================= */
.auth-container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 1rem;
  position: relative;
  overflow: hidden;
  background-color: #F9FAFB;
  background-image: 
      linear-gradient(#E5E7EB 1px, transparent 1px),
      linear-gradient(90deg, #E5E7EB 1px, transparent 1px);
  background-size: 40px 40px;
}

.auth-container::before {
    content: '';
    position: absolute;
    top: -10%; left: -10%;
    width: 600px; height: 600px;
    background: radial-gradient(circle, rgba(37,99,235,0.15) 0%, rgba(255,255,255,0) 70%);
    border-radius: 50%;
    z-index: 0;
    pointer-events: none;
}

.auth-container::after {
    content: '';
    position: absolute;
    bottom: -10%; right: -10%;
    width: 500px; height: 500px;
    background: radial-gradient(circle, rgba(236,72,153,0.1) 0%, rgba(255,255,255,0) 70%);
    border-radius: 50%;
    z-index: 0;
    pointer-events: none;
}

.auth-card {
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  width: 100%;
  max-width: 420px;
  padding: 2.5rem;
  border-radius: 1.5rem;
  box-shadow: 0 20px 40px -5px rgba(0, 0, 0, 0.1), 0 10px 15px -5px rgba(0, 0, 0, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.6);
  z-index: 1;
}

.auth-header { text-align: center; margin-bottom: 1.5rem; }
.auth-header h1 { font-size: 1.75rem; font-weight: 800; margin-bottom: 0.5rem; color: #111827; }
.auth-header p { color: #4B5563; font-size: 0.95rem; }

/* Social Login Buttons */
.social-auth-wrapper {
    margin-bottom: 1.5rem;
    display: grid;
    grid-auto-flow: column;       /* 自动按列排列（水平方向）*/
    grid-auto-columns: max-content; /* 或者用 auto/min-content */
    justify-content: center;
}

.social-btn {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    padding: 0.75rem;
    background: white;
    border: 1px solid #E5E7EB;
    border-radius: 0.75rem;
    color: #374151;
    font-weight: 500;
    font-size: 0.95rem;
    transition: all 0.2s;
    cursor: pointer;
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

.social-btn:hover {
    background: #F9FAFB;
    border-color: #D1D5DB;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.auth-divider {
    display: flex;
    align-items: center;
    text-align: center;
    margin: 1.5rem 0;
    color: #9CA3AF;
    font-size: 0.85rem;
}

.auth-divider::before, .auth-divider::after {
    content: '';
    flex: 1;
    border-bottom: 1px solid #E5E7EB;
}

.auth-divider span {
    padding: 0 0.75rem;
}

.auth-form { display: flex; flex-direction: column; gap: 0; }

.form-group { display: flex; flex-direction: column; gap: 0.5rem; text-align: left; }
.form-label { font-size: 0.9rem; font-weight: 600; color: #111827; }

/* New Input Styles (Matching Member Page) */
.v-input-group { position: relative; margin-bottom: 1.25rem; padding-top: 0; }
.v-input, .v-textarea {
  width: 100%; padding: 12px 12px; border: 1px solid #e5e7eb; border-radius: 8px;
  outline: none; transition: border-color 0.2s, box-shadow 0.2s; background: white; font-size: 0.95rem;
}
.v-input:focus, .v-textarea:focus { border-color: var(--primary-color); border-width: 2px; padding: 11px 11px; }
.v-label {
  position: absolute; left: 12px; top: 14px; background: white; padding: 0 4px;
  color: #6b7280; font-size: 0.95rem; transition: all 0.2s; pointer-events: none; line-height: 1;
}
.v-input:focus + .v-label, .v-input:not(:placeholder-shown) + .v-label,
.v-textarea:focus + .v-label, .v-textarea:not(:placeholder-shown) + .v-label {
  top: 0; transform: translateY(-50%) scale(0.85); left: 10px; color: var(--primary-color); font-weight: 500;
}

/* Auth Specific Verification Layout */
.auth-verify-row {
    display: flex; gap: 10px; margin-bottom: 1.25rem;
}
.auth-verify-row .v-input-group {
    margin-bottom: 0; flex: 1;
}
.verify-code-btn {
    padding: 0 1rem;
    font-size: 0.9rem;
    color: var(--primary-color);
    border: 1px solid #E5E7EB;
    border-radius: 8px;
    background: white;
    font-weight: 500;
    transition: all 0.2s;
    white-space: nowrap;
    min-width: 100px;
}
.verify-code-btn:hover:not(:disabled) {
    background: #EFF6FF; border-color: var(--primary-color);
}
.verify-code-btn:disabled {
    color: #9CA3AF; background: #F3F4F6; cursor: not-allowed;
}

.auth-btn {
  background-color: #111827;
  color: white;
  padding: 0.875rem;
  border-radius: 0.75rem;
  font-weight: 600;
  margin-top: 0.5rem;
  transition: all 0.2s;
  box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
  width: 100%;
}
.auth-btn:hover { 
    opacity: 0.9; 
    transform: translateY(-1px);
    box-shadow: 0 6px 10px -1px rgba(0,0,0,0.15);
}

.auth-footer { margin-top: 1.5rem; text-align: center; font-size: 0.9rem; color: #4B5563; }
.auth-link { color: var(--primary-color); font-weight: 600; cursor: pointer; }
.auth-link:hover { text-decoration: underline; }

/* Mobile Adaptation */
@media (max-width: 768px) {
  .hero-title { font-size: 2.5rem; }
  
  /* Optimize subtitle size for mobile */
  .hero-subtitle {
      font-size: 0.8rem; /* Smaller for mobile */
      line-height: 1.4;
      margin-bottom: 2rem;
      padding: 0 0.5rem;
  }
  .subtitle-highlight {
      font-size: 0.7rem; /* Smaller to fit one line */
      margin-top: 0.5rem;
      overflow: hidden; /* Prevent breaking layout */
      text-overflow: ellipsis;
      display: block;
      letter-spacing: -0.02em;
  }

  .input-group-wrapper {
      width: 100%;
      max-width: 100%; 
      padding: 4px 6px; 
      margin-left: 0;
      margin-right: 0;
  }
  .input-prefix {
      font-size: 0.9rem; 
      padding-left: 0.5rem;
      padding-right: 0.25rem;
  }
  .main-input { font-size: 0.95rem; }
  .cta-button { padding: 0 1rem; height: 2.8rem; font-size: 0.9rem; }
}

/* --- Drag & Drop Visuals --- */
.module-item.dragging {
    opacity: 0.5;
    background: #F3F4F6;
    border: 2px dashed #9CA3AF;
    box-shadow: none;
}
.module-item.dragging > * {
    opacity: 0.2;
}

.dragging-ghost {
    position: fixed;
    z-index: 10000;
    pointer-events: none;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    background: white;
    opacity: 0.95;
    transform: scale(1.05) rotate(3deg) !important;
    border-radius: 0.75rem;
    transition: transform 0.1s ease;
}

body.is-dragging {
    cursor: grabbing;
    user-select: none;
}
/* Loading Overlay */
#global-page-loader {
    position: fixed; inset: 0; background: #ffffffee; z-index: 99999;
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    transition: opacity 0.4s ease;
}
#global-page-loader.fade-out { opacity: 0; pointer-events: none; }
.loader-spinner {
    width: 40px; height: 40px; border: 3px solid #E5E7EB;
    border-top-color: var(--primary-color); border-radius: 50%;
    animation: spin 0.8s linear infinite; margin-bottom: 1rem;
}
.loader-text { color: #6B7280; font-size: 0.9rem; font-weight: 500; }