/* ==========================================================================
   星禾乐学 - 公共样式表 (Common CSS)
   版本: 1.0 | 最后更新: 2026-08-05
   覆盖: 全局变量、Reset、布局骨架、通用组件
   ========================================================================== */

/* ===== CSS 变量 ===== */
:root {
  --blue-start: #5BA8F5;
  --blue-end: #4A90E2;
  --primary: #5BA8F5;
  --blue: #4A90E2;
  --bg-start: #E8F4FD;
  --bg-end: #FFFFFF;
  --radius-sm: clamp(10px, 2vw, 14px);
  --radius-md: clamp(14px, 2.5vw, 20px);
  --radius-lg: clamp(16px, 3vw, 24px);
  --gap-sm: clamp(8px, 1.5vw, 14px);
  --gap-md: clamp(10px, 2vw, 18px);
  --pad-sm: clamp(10px, 2vw, 16px);
  --pad-md: clamp(14px, 2.5vw, 24px);
  --pad-lg: clamp(16px, 3vw, 32px);
}

/* ===== 全局 Reset ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: #e8ecf1;
  color: #333;
  min-height: 100vh;
  line-height: 1.5;
}

a {
  color: var(--blue-start);
  text-decoration: none;
}

/* ===== 应用容器 (.app-wrap) ===== */
.app-wrap {
  width: 100%;
  min-height: 100vh;
  background: linear-gradient(180deg, var(--bg-start) 0%, var(--bg-end) 50%);
  overflow-x: hidden;
}

@media (min-width: 768px) {
  body {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: clamp(16px, 3vh, 40px) 0;
  }

  .app-wrap {
    max-width: 1100px;
    min-height: auto;
    border-radius: 20px;
    box-shadow: 0 8px 40px rgba(0, 0, 0, .08);
  }
}

/* ===== Footer - ICP 备案 ===== */
.footer-icp {
  text-align: center;
  padding: clamp(16px, 2.5vw, 24px) 0 clamp(24px, 3.5vw, 36px);
}

.footer-icp a {
  font-size: clamp(11px, 1.4vw, 13px);
  color: #999;
  text-decoration: none;
}

.footer-icp a:hover {
  color: #666;
}

/* ===== Toast 提示 ===== */
.toast {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(0, 0, 0, .78);
  color: #fff;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 14px;
  z-index: 999;
  pointer-events: none;
  opacity: 0;
  transition: opacity .3s;
}

.toast.show {
  opacity: 1;
}

/* ===== Loading 加载 ===== */
.loading {
  text-align: center;
  color: #94a3b8;
  padding: 40px 0;
  font-size: 14px;
}

/* ===== 顶部提示条 ===== */
.top-tip {
  background: #f5f5f5;
  text-align: center;
  padding: 6px 0;
  font-size: clamp(11px, 1.4vw, 13px);
  color: #999;
}

/* ===== 用户头部公共（user.html / vip.html 共享） ===== */
.user-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: clamp(230px, 60vw, 340px);
  background: linear-gradient(135deg, var(--primary) 0%, var(--blue-end) 100%);
  border-radius: 0 0 clamp(30px, 5vw, 50px) clamp(30px, 5vw, 50px);
  box-shadow: 0 4px 14px rgba(74, 144, 226, .15);
}

@media (min-width: 768px) {
  .user-bg {
    border-radius: 0 0 40px 40px;
  }
}

.user-header {
  position: relative;
  padding-top: clamp(20px, 3vw, 30px);
  width: 100%;
}

.user-card {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: clamp(30px, 5vw, 50px) var(--pad-lg) clamp(20px, 3vw, 36px);
}

.user-avatar-wrap {
  position: relative;
  margin-bottom: clamp(10px, 1.5vw, 16px);
}

.user-avatar {
  width: clamp(80px, 13vw, 120px);
  height: clamp(80px, 13vw, 120px);
  border-radius: 50%;
  border: 4px solid rgba(255, 255, 255, .5);
  background: rgba(255, 255, 255, .3);
  object-fit: cover;
}

.user-nick {
  font-size: clamp(18px, 3vw, 24px);
  font-weight: bold;
  color: #fff;
  margin-bottom: clamp(4px, .6vw, 8px);
}

.login-hint {
  opacity: .8;
  text-decoration: underline;
  cursor: pointer;
}

.points-row {
  display: flex;
  align-items: center;
  background: rgba(0, 0, 0, .15);
  padding: clamp(6px, 1vw, 10px) clamp(16px, 2.5vw, 28px);
  border-radius: 20px;
}

.points-val {
  font-size: clamp(14px, 2vw, 17px);
  color: #fff;
  font-weight: 600;
  text-shadow: 0 1px 3px rgba(0, 0, 0, .2);
}

/* ===== 章节标题 ===== */
.section-title {
  font-size: clamp(16px, 2.4vw, 20px);
  font-weight: bold;
  color: #333;
}

/* ===== 返回首页链接 ===== */
.back-link {
  display: block;
  text-align: center;
  margin-top: 18px;
  color: #999;
  font-size: 14px;
  text-decoration: none;
}