* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
body {
  background: #f4f7ff;
  color: #222;
}
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
}
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 0;
  border-bottom: 1px solid #e5e7eb;
}
.logo {
  font-size: 24px;
  font-weight: bold;
  color: #165DFF;
}
.btn {
  padding: 8px 16px;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  margin-left: 8px;
  font-size: 14px;
}
.btn-primary {
  background: #165DFF;
  color: white;
}
.btn-danger {
  background: #ff4d4f;
  color: white;
  display: none;
}
.user-info {
  margin-right: 10px;
  color: #165DFF;
  font-weight: 500;
  display: none;
}
.main {
  margin-top: 40px;
  display: flex;
  justify-content: center;
}
.ai-card {
  width: 100%;
  max-width: 750px;
  background: white;
  border-radius: 16px;
  padding: 30px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.05);
}
.ai-card h2 {
  margin-bottom: 20px;
  color: #333;
}
textarea {
  width: 100%;
  height: 140px;
  border: 1px solid #ddd;
  border-radius: 10px;
  padding: 14px;
  font-size: 15px;
  resize: none;
  margin-bottom: 16px;
}
.result-box {
  margin-top: 24px;
  padding: 18px;
  background: #f9fafb;
  border-radius: 10px;
  white-space: pre-wrap;
  line-height: 1.6;
}
.modal {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.4);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 999;
}
.modal-box {
  background: white;
  width: 380px;
  padding: 30px;
  border-radius: 16px;
  position: relative;
}
.modal-close {
  position: absolute;
  right: 16px; top: 14px;
  font-size: 22px;
  cursor: pointer;
}
.modal-box input {
  width: 100%;
  padding: 12px;
  margin: 8px 0;
  border: 1px solid #ddd;
  border-radius: 8px;
}