:root {
  --jd-primary: #0047ab;
  --jd-primary-dark: #003380;
  --jd-primary-light: #e6eef8;
  --jd-bg: #f5f7fa;
  --jd-surface: #ffffff;
  --jd-text: #1f2937;
  --jd-text-secondary: #6b7280;
  --jd-border: #e5e7eb;
  --jd-accent-red: #b91c1c;
  --jd-shadow: rgba(0, 55, 128, 0.08);
}

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

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  background: var(--jd-bg);
  color: var(--jd-text);
}

.chat-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  max-width: 960px;
  margin: 0 auto;
  background: var(--jd-surface);
  box-shadow: 0 0 40px var(--jd-shadow);
}

.chat-header {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 24px;
  background: linear-gradient(135deg, var(--jd-primary) 0%, var(--jd-primary-dark) 100%);
  color: #fff;
  flex-shrink: 0;
  position: relative;
  overflow: hidden;
}

.chat-header::after {
  content: "";
  position: absolute;
  right: -40px;
  top: -40px;
  width: 160px;
  height: 160px;
  background: radial-gradient(circle, rgba(255,255,255,0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.header-avatar {
  width: 46px;
  height: 46px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.95);
  color: var(--jd-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  font-weight: 700;
  flex-shrink: 0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
  font-family: "STKaiti", "KaiTi", "SimKaiti", "楷体", serif;
  letter-spacing: 2px;
  padding-left: 2px;
}

.header-info {
  min-width: 0;
  z-index: 1;
}

.header-title {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: 0.5px;
}

.header-subtitle {
  font-size: 12px;
  opacity: 0.9;
  line-height: 1.4;
  margin-top: 2px;
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  background:
    radial-gradient(circle at 90% 10%, rgba(0, 71, 171, 0.03) 0%, transparent 25%),
    radial-gradient(circle at 10% 90%, rgba(0, 71, 171, 0.03) 0%, transparent 25%),
    var(--jd-bg);
}

.message {
  display: flex;
  gap: 12px;
  max-width: 82%;
  animation: message-in 0.25s ease-out;
}

@keyframes message-in {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.message.user {
  align-self: flex-end;
  flex-direction: row-reverse;
}

.message.assistant {
  align-self: flex-start;
}

.message-avatar {
  width: 38px;
  height: 38px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.message-avatar svg {
  width: 100%;
  height: 100%;
}

.message-content {
  padding: 14px 18px;
  border-radius: 10px;
  font-size: 15px;
  line-height: 1.75;
  word-break: break-word;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.message.user .message-content {
  background: linear-gradient(135deg, var(--jd-primary) 0%, var(--jd-primary-dark) 100%);
  color: #fff;
  border-bottom-right-radius: 3px;
}

.message.assistant .message-content {
  background: var(--jd-surface);
  color: var(--jd-text);
  border-bottom-left-radius: 3px;
  border: 1px solid var(--jd-border);
  border-left: 3px solid var(--jd-primary);
}

.message-content p {
  margin-bottom: 10px;
}

.message-content p:last-child {
  margin-bottom: 0;
}

.message-content ul,
.message-content ol {
  margin-left: 22px;
  margin-bottom: 10px;
}

.message-content li {
  margin-bottom: 6px;
}

.message-content a {
  color: var(--jd-primary);
  text-decoration: none;
  border-bottom: 1px solid var(--jd-primary-light);
  transition: border-color 0.2s;
}

.message-content a:hover {
  border-color: var(--jd-primary);
}

.message-content code {
  background: rgba(0, 71, 171, 0.08);
  color: var(--jd-primary-dark);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: "SF Mono", "JetBrains Mono", monospace;
  font-size: 13px;
}

.message-content img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
  display: block;
  margin: 8px 0;
  border: 1px solid var(--jd-border);
}

.message-loading .dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--jd-primary);
  margin-right: 4px;
  opacity: 0.5;
  animation: loading 1.4s infinite ease-in-out both;
}

.message-loading .dot:nth-child(1) { animation-delay: -0.32s; }
.message-loading .dot:nth-child(2) { animation-delay: -0.16s; }

@keyframes loading {
  0%, 80%, 100% { transform: scale(0.6); opacity: 0.4; }
  40% { transform: scale(1); opacity: 1; }
}

.chat-input-area {
  padding: 16px 24px 20px;
  background: var(--jd-surface);
  border-top: 1px solid var(--jd-border);
  flex-shrink: 0;
}

.input-wrapper {
  display: flex;
  gap: 12px;
  align-items: flex-end;
  background: var(--jd-bg);
  border-radius: 12px;
  padding: 10px 10px 10px 18px;
  border: 1px solid var(--jd-border);
  transition: border-color 0.2s, box-shadow 0.2s, background 0.2s;
}

.input-wrapper:focus-within {
  background: var(--jd-surface);
  border-color: var(--jd-primary);
  box-shadow: 0 0 0 3px var(--jd-primary-light);
}

#input {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  font-size: 15px;
  line-height: 1.6;
  max-height: 132px;
  min-height: 26px;
  resize: none;
  font-family: inherit;
  padding: 4px 0;
  color: var(--jd-text);
}

#input::placeholder {
  color: #9ca3af;
}

#send-btn {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  border: none;
  background: var(--jd-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.2s, opacity 0.2s, transform 0.15s;
  flex-shrink: 0;
}

#send-btn:hover:not(:disabled) {
  background: var(--jd-primary-dark);
  transform: translateY(-1px);
}

#send-btn:disabled {
  background: #d1d5db;
  cursor: not-allowed;
}

#send-btn svg {
  width: 18px;
  height: 18px;
}

.input-hint {
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
  font-size: 12px;
  color: var(--jd-text-secondary);
}

.input-hint .warning {
  color: var(--jd-accent-red);
  font-weight: 500;
}

@media (max-width: 768px) {
  .chat-container {
    max-width: 100%;
    box-shadow: none;
  }

  .chat-header {
    padding: 14px 18px;
  }

  .chat-messages {
    padding: 18px;
    gap: 16px;
  }

  .message {
    max-width: 90%;
  }

  .chat-input-area {
    padding: 12px 16px 16px;
  }
}

@media (max-width: 380px) {
  .header-subtitle {
    display: none;
  }

  .header-avatar {
    width: 40px;
    height: 40px;
    font-size: 18px;
  }
}