:root {
  --primary: #2563eb;
  --success: #10b981;
  --danger: #ef4444;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #1e293b;
  --text-light: #64748b;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* 导航 */
header {
  background: var(--card-bg);
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

nav {
  max-width: 900px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo { font-size: 1.3rem; font-weight: 700; color: var(--primary); }

/* 主区域 */
main {
  flex: 1;
  max-width: 900px;
  margin: 0 auto;
  padding: 3rem 2rem;
  width: 100%;
}

.result-panel img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 0 auto;
}

.hello { 
  font-size: 1.3rem; 
  font-weight: 700; 
  color: var(--primary); 
  display: grid;
  place-items: center;
}

.btn {
    display: inline-block;
    padding: 10px 20px;
    font-size: 16px;
    color: white;
    background-color: #007bff; /* 蓝色背景，和你图片里的主题色类似 */
    text-decoration: none; /* 去掉链接的下划线 */
    border-radius: 5px; /* 圆角 */
    margin-top: 20px; /* 距离上面的 Hello World 有一点间距 */
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #0056b3; /* 鼠标悬停时颜色变深 */
}

/* 页脚 */
footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--text-light);
  font-size: 0.85rem;
}

@media (max-width: 600px) {
  
}