/* ========== CSS Variables ========== */
:root {
  --primary: #e74c3c;
  --primary-dark: #c0392b;
  --primary-light: #ff6b5a;
  --bg: #0a0a0f;
  --bg-card: #12121a;
  --bg-card-hover: #1a1a28;
  --text: #e8e8f0;
  --text-secondary: #8888a0;
  --border: #2a2a3a;
  --radius: 16px;
  --radius-sm: 10px;
}

/* ========== Reset ========== */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: var(--primary-light); text-decoration: none; transition: opacity 0.2s; }
a:hover { opacity: 0.8; }
img { max-width: 100%; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }

/* ========== Navigation ========== */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-content {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.logo { font-size: 1.3rem; font-weight: 700; color: var(--text) !important; }
.nav-links { display: flex; list-style: none; gap: 28px; }
.nav-links a { color: var(--text-secondary) !important; font-size: 0.95rem; }
.nav-links a:hover { color: var(--text) !important; }

/* ========== Hero ========== */
.hero {
  padding: 100px 0 80px;
  text-align: center;
  background: radial-gradient(ellipse at 50% 0%, rgba(231, 76, 60, 0.08) 0%, transparent 70%);
}
.hero h1 { font-size: 3.2rem; font-weight: 800; line-height: 1.2; margin-bottom: 20px; }
.hero .highlight { background: linear-gradient(135deg, var(--primary-light), #ff9a56); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.hero-sub { font-size: 1.15rem; color: var(--text-secondary); max-width: 600px; margin: 0 auto 36px; }
.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ========== Buttons ========== */
.btn {
  display: inline-block; padding: 14px 32px; border-radius: 50px;
  font-size: 1rem; font-weight: 600; transition: all 0.2s; cursor: pointer;
  border: 2px solid transparent;
}
.btn-primary { background: var(--primary); color: #fff !important; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(231, 76, 60, 0.3); }
.btn-secondary { background: transparent; border-color: var(--border); color: var(--text) !important; }
.btn-secondary:hover { border-color: var(--primary); }
.btn-large { padding: 18px 48px; font-size: 1.1rem; }

/* ========== Section ========== */
.section { padding: 80px 0; }
.section-title { text-align: center; font-size: 2rem; font-weight: 700; margin-bottom: 48px; }
.section-actions { text-align: center; margin-top: 40px; }

/* ========== Workflow Steps ========== */
.steps {
  display: flex; align-items: center; justify-content: center; gap: 24px; flex-wrap: wrap;
}
.step-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 36px 28px; text-align: center; width: 260px; position: relative;
  transition: all 0.3s;
}
.step-card:hover { background: var(--bg-card-hover); transform: translateY(-4px); }
.step-num {
  position: absolute; top: -14px; left: 50%; transform: translateX(-50%);
  background: var(--primary); color: #fff; width: 28px; height: 28px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center; font-size: 0.85rem; font-weight: 700;
}
.step-icon { font-size: 2.4rem; margin-bottom: 12px; }
.step-card h3 { margin-bottom: 8px; }
.step-card p { color: var(--text-secondary); font-size: 0.9rem; }
.step-arrow { font-size: 1.5rem; color: var(--text-secondary); }

/* ========== Feature Grid ========== */
.feature-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.feature-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 32px 24px; transition: all 0.3s;
}
.feature-card:hover { background: var(--bg-card-hover); transform: translateY(-3px); }
.feat-icon { font-size: 2.4rem; margin-bottom: 12px; }
.feature-card h3 { margin-bottom: 8px; font-size: 1.1rem; }
.feature-card p { color: var(--text-secondary); font-size: 0.92rem; margin-bottom: 12px; }
.feat-tag {
  display: inline-block; padding: 3px 12px; border-radius: 50px;
  background: rgba(231, 76, 60, 0.15); color: var(--primary-light); font-size: 0.8rem; font-weight: 600;
}

/* ========== Scenarios / Dialogue ========== */
.scenario { margin-bottom: 40px; }
.scenario h3 { margin-bottom: 16px; font-size: 1.15rem; }
.dialogue { display: flex; flex-direction: column; gap: 12px; }
.msg {
  max-width: 80%; padding: 14px 20px; border-radius: var(--radius-sm);
  font-size: 0.95rem; line-height: 1.6;
}
.msg.user {
  align-self: flex-start;
  background: rgba(231, 76, 60, 0.1); border: 1px solid rgba(231, 76, 60, 0.2);
  color: var(--text);
}
.msg.ai {
  align-self: flex-end;
  background: var(--bg-card); border: 1px solid var(--border);
  color: var(--text-secondary);
}

/* ========== CTA ========== */
.cta {
  text-align: center;
  background: radial-gradient(ellipse at 50% 100%, rgba(231, 76, 60, 0.06) 0%, transparent 70%);
}
.cta h2 { font-size: 2.2rem; margin-bottom: 12px; }
.cta p { color: var(--text-secondary); margin-bottom: 32px; font-size: 1.1rem; }

/* ========== Footer ========== */
.footer {
  border-top: 1px solid var(--border); padding: 48px 0 0;
}
.footer-content { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; margin-bottom: 32px; }
.footer-brand h3 { font-size: 1.2rem; margin-bottom: 8px; }
.footer-brand p { color: var(--text-secondary); font-size: 0.9rem; }
.footer-links h4, .footer-contact h4 { margin-bottom: 12px; font-size: 0.95rem; }
.footer-links ul { list-style: none; }
.footer-links li { margin-bottom: 6px; }
.footer-links a { color: var(--text-secondary) !important; font-size: 0.9rem; }
.footer-contact p { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 4px; }
.footer-bottom {
  border-top: 1px solid var(--border); padding: 16px 0; text-align: center;
  color: var(--text-secondary); font-size: 0.85rem;
}

/* ========== Page Header ========== */
.page-header {
  padding: 80px 0 40px; text-align: center;
}
.page-header h1 { font-size: 2.4rem; margin-bottom: 12px; }
.page-header p { color: var(--text-secondary); font-size: 1.05rem; max-width: 600px; margin: 0 auto; }

/* ========== Feature Detail Page ========== */
.feature-detail-grid { display: grid; gap: 32px; }
.feature-detail {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 36px;
}
.feature-detail .feat-icon { font-size: 2.8rem; }
.feature-detail h3 { font-size: 1.3rem; margin-bottom: 12px; }
.feature-detail p { color: var(--text-secondary); margin-bottom: 16px; }
.feature-detail ul { list-style: none; margin-top: 12px; }
.feature-detail li { padding: 6px 0; color: var(--text-secondary); }
.feature-detail li::before { content: "✓ "; color: var(--primary-light); font-weight: 700; }

/* ========== Download Page ========== */
.download-cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; max-width: 800px; margin: 0 auto; }
.download-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 40px 32px; text-align: center; transition: all 0.3s;
}
.download-card:hover { background: var(--bg-card-hover); transform: translateY(-4px); }
.download-icon { font-size: 3rem; margin-bottom: 16px; }
.download-card h3 { font-size: 1.2rem; margin-bottom: 8px; }
.download-card p { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 20px; }
.download-card .btn { display: inline-block; }

/* ========== Guide Page ========== */
.guide-steps { max-width: 700px; margin: 0 auto; }
.guide-step {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; margin-bottom: 20px;
}
.guide-step h3 { margin-bottom: 8px; }
.guide-step p { color: var(--text-secondary); font-size: 0.95rem; }
.guide-step code {
  display: inline-block; background: rgba(255,255,255,0.05); padding: 2px 8px;
  border-radius: 4px; font-size: 0.85rem;
}

/* ========== Help Center ========== */
.help-search { text-align: center; margin-bottom: 48px; }
.help-search input {
  width: 100%; max-width: 500px; padding: 14px 20px; border-radius: 50px;
  background: var(--bg-card); border: 1px solid var(--border);
  color: var(--text); font-size: 1rem; outline: none;
}
.help-search input:focus { border-color: var(--primary); }
.help-categories { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.help-category {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px;
}
.help-category h3 { margin-bottom: 16px; font-size: 1.1rem; }
.help-item {
  padding: 10px 0; border-bottom: 1px solid var(--border); cursor: pointer;
  display: flex; justify-content: space-between; align-items: center;
}
.help-item:hover { color: var(--primary-light); }
.help-item:last-child { border-bottom: none; }
.help-item .arrow { color: var(--text-secondary); font-size: 0.85rem; }

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .hero { padding: 60px 0 40px; }
  .feature-grid { grid-template-columns: 1fr; }
  .download-cards { grid-template-columns: 1fr; }
  .steps { flex-direction: column; }
  .step-arrow { transform: rotate(90deg); }
  .footer-content { grid-template-columns: 1fr; gap: 24px; }
  .nav-links { gap: 16px; font-size: 0.85rem; }
  .help-categories { grid-template-columns: 1fr; }
  .feature-detail-grid { gap: 20px; }
}

/* ========== Showcase / Video Section ========== */
.showcase-section {
  position: relative;
  overflow: hidden;
}
.particle-grid {
  position: absolute; inset: 0;
  background-image: radial-gradient(rgba(231,76,60,0.06) 1px, transparent 1px);
  background-size: 30px 30px;
  pointer-events: none;
}
.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 640px;
  margin: -32px auto 48px;
}
.video-container {
  position: relative;
  max-width: 960px;
  margin: 0 auto;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 8px 40px rgba(231, 76, 60, 0.2);
  background: #000;
}
.video-container video {
  display: block;
  width: 100%;
  height: auto;
  max-height: 540px;
  object-fit: contain;
  background: #000;
}
.showcase-cta {
  text-align: center;
  margin-top: 40px;
}
.showcase-cta p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 20px;
}

/* ========== Workflow Steps Enhancement ========== */
@media (min-width: 769px) {
  .steps {
    flex-wrap: nowrap;
    gap: 0;
    justify-content: center;
    align-items: stretch;
    overflow: hidden;
  }
  .step-card {
    flex: 1 1 0%;
    min-width: 160px;
    max-width: 240px;
    padding: 36px 16px;
  }
  .step-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--text-secondary);
    padding: 0 6px;
    align-self: center;
    margin-top: 18px;
    flex-shrink: 0;
  }
}

/* ========== Login Button ========== */
.nav-login-btn {
  background: linear-gradient(135deg, #667eea, #764ba2) !important;
  color: #fff !important;
  padding: 8px 20px !important;
  border-radius: 50px !important;
  font-weight: 600 !important;
  font-size: 0.9rem !important;
  transition: all 0.3s ease !important;
  box-shadow: 0 4px 15px rgba(102,126,234,0.3) !important;
}
.nav-login-btn:hover {
  opacity: 0.9 !important;
  transform: translateY(-2px) !important;
  box-shadow: 0 6px 25px rgba(102,126,234,0.45) !important;
}