* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(96, 165, 250, 0.18), transparent 32%),
    radial-gradient(circle at top right, rgba(59, 130, 246, 0.16), transparent 28%),
    linear-gradient(180deg, #eef4ff 0%, #f7f9fc 52%, #eef3fb 100%);
  color: #0f172a;
  min-height: 100vh;
}

button,
input,
textarea {
  font: inherit;
}

.page-shell {
  max-width: 1280px;
  margin: 0 auto;
  padding: 36px 24px 48px;
}

.hero {
  margin-bottom: 28px;
}

.hero-badge,
.login-badge,
.section-tip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(148, 163, 184, 0.22);
  color: #2563eb;
  font-size: 12px;
  font-weight: 700;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

h1 {
  margin: 16px 0 10px;
  font-size: 42px;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.hero-desc {
  margin: 0 0 24px;
  max-width: 760px;
  color: #475569;
  font-size: 16px;
  line-height: 1.7;
}

.card {
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid rgba(148, 163, 184, 0.16);
  border-radius: 24px;
  box-shadow: 0 18px 50px rgba(15, 23, 42, 0.08);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 18px;
}

.section-head h2 {
  margin: 0;
  font-size: 22px;
}

.ai-panel {
  padding: 24px;
}

.ai-chat-box {
  min-height: 180px;
  max-height: 360px;
  overflow-y: auto;
  padding: 16px;
  border-radius: 18px;
  background: rgba(248, 250, 252, 0.9);
  border: 1px solid rgba(203, 213, 225, 0.7);
}

.ai-message {
  max-width: 86%;
  padding: 12px 14px;
  border-radius: 14px;
  margin-bottom: 12px;
  line-height: 1.6;
  font-size: 14px;
}

.ai-message-user {
  margin-left: auto;
  background: #dbeafe;
  color: #1e3a8a;
}

.ai-message-system {
  background: #f1f5f9;
  color: #334155;
}

.quick-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.quick-btn,
.ghost-btn {
  padding: 10px 14px;
  border-radius: 14px;
  border: 1px solid rgba(148, 163, 184, 0.26);
  background: rgba(255, 255, 255, 0.72);
  color: #1e293b;
  cursor: pointer;
  transition: 0.2s ease;
}

.quick-btn:hover,
.ghost-btn:hover {
  transform: translateY(-1px);
  background: rgba(255, 255, 255, 0.92);
}

.ai-input-row {
  display: grid;
  grid-template-columns: 1fr 140px;
  gap: 14px;
  margin-top: 18px;
}

.ai-input-row textarea {
  min-height: 92px;
  padding: 14px 16px;
  border-radius: 18px;
  border: 1px solid rgba(148, 163, 184, 0.28);
  background: rgba(255, 255, 255, 0.84);
  resize: vertical;
  outline: none;
}

.primary-btn {
  border: none;
  border-radius: 18px;
  background: linear-gradient(135deg, #2563eb, #3b82f6);
  color: #fff;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 10px 24px rgba(37, 99, 235, 0.24);
  transition: 0.2s ease;
}

.primary-btn:hover {
  transform: translateY(-1px);
  opacity: 0.96;
}

.content-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 24px;
}

.feature-card {
  padding: 24px;
}

.card-icon {
  font-size: 28px;
  margin-bottom: 12px;
}

.feature-card h3 {
  margin: 0 0 10px;
  font-size: 22px;
}

.feature-card p {
  margin: 0;
  line-height: 1.7;
  color: #475569;
}

.card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 18px;
}

.usage {
  padding: 24px;
}

.usage-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.usage-item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 18px;
  border-radius: 18px;
  background: rgba(248, 250, 252, 0.78);
  border: 1px solid rgba(226, 232, 240, 0.8);
}

.usage-step {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #dbeafe;
  color: #1d4ed8;
  font-weight: 800;
  flex-shrink: 0;
}

.usage-item h4 {
  margin: 0 0 6px;
  font-size: 16px;
}

.usage-item p {
  margin: 0;
  color: #475569;
  line-height: 1.6;
  font-size: 14px;
}

/* 登录层 */
.login-overlay {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(15, 23, 42, 0.24);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  z-index: 999;
}

.login-overlay.hidden {
  display: none;
}

.login-glass {
  width: min(92vw, 420px);
  padding: 28px;
  border-radius: 28px;
  background: rgba(255, 255, 255, 0.24);
  border: 1px solid rgba(255, 255, 255, 0.28);
  box-shadow: 0 22px 60px rgba(15, 23, 42, 0.22);
  backdrop-filter: blur(22px);
  -webkit-backdrop-filter: blur(22px);
}

.login-glass h2 {
  margin: 16px 0 8px;
  font-size: 28px;
}

.login-desc {
  margin: 0 0 18px;
  color: rgba(15, 23, 42, 0.72);
}

.login-form {
  display: grid;
  gap: 12px;
}

.login-form input {
  padding: 12px 14px;
  border-radius: 16px;
  border: 1px solid rgba(148, 163, 184, 0.28);
  background: rgba(255, 255, 255, 0.78);
  outline: none;
}

.login-btn {
  height: 48px;
  margin-top: 4px;
}

.login-error {
  min-height: 22px;
  margin-top: 12px;
  color: #dc2626;
  font-size: 14px;
}

@media (max-width: 900px) {
  .content-grid,
  .usage-list,
  .ai-input-row {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 32px;
  }

  .page-shell {
    padding: 24px 16px 36px;
  }
}