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

body {
  font-family: Arial, sans-serif;
  background: #f5f5f5;
}

.container {
  max-width: 500px;
  margin: 0 auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  min-height: 100vh;
}

/* 图片100%宽度 */
img {
  width: 100%;
  height: auto;
  border-radius: 12px;
  display: block;
}

/* 按钮和图片一样宽 */
.btn-box {
  width: 100%;
}

/* 大按钮：全屏宽 + 更大更高 */
.dynamic-btn {
  display: block;
  width: 100%;
  padding: 22px 20px;
  background: #ff4d6d;
  color: white;
  font-size: 20px;
  font-weight: bold;
  text-decoration: none;
  border-radius: 12px;
  text-align: center;
  transition: all 0.3s ease;
  box-shadow: 0 6px 15px rgba(255,77,109,0.3);
  cursor: pointer;
}

.dynamic-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 20px rgba(255,77,109,0.4);
  background: #ff3366;
}