/* 图标样式 - 使用CSS和Unicode字符 */
.icon-search::before {
    content: "🔍";
    font-size: 18px;
    display: inline-block;
}

.icon-user::before {
    content: "👤";
    font-size: 20px;
    display: inline-block;
}

.icon-arrow-right::after {
    content: "→";
    margin-left: 4px;
}

.icon-arrow-left::before {
    content: "←";
    margin-right: 4px;
}

/* 纯CSS搜索图标 */
.icon-search-css {
    width: 20px;
    height: 20px;
    border: 2px solid #999;
    border-radius: 50%;
    position: relative;
    display: inline-block;
}

.icon-search-css::after {
    content: "";
    width: 8px;
    height: 2px;
    background: #999;
    position: absolute;
    bottom: -6px;
    right: -6px;
    transform: rotate(45deg);
}

/* 头像占位符 */
.avatar-placeholder {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-weight: 600;
    font-size: 14px;
}

.avatar-placeholder-large {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-weight: 600;
    font-size: 36px;
    border: 4px solid rgba(255,255,255,0.3);
}

/* 课程封面占位符 */
.course-cover-placeholder {
    width: 100%;
    height: 100%;
    min-height: 180px;
    max-height: 180px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 48px;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
    flex-shrink: 0;
    box-sizing: border-box;
}

.course-cover-placeholder::before {
    content: "📚";
    font-size: 64px;
    opacity: 0.3;
    position: absolute;
}

/* Logo文字样式 */
.logo-text {
    font-size: 24px;
    font-weight: 700;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-decoration: none;
    display: inline-block;
}

/* 课程卡片图片严格限制 */
#course-list {
    display: grid !important;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)) !important;
    gap: 24px !important;
    list-style: none !important;
    padding: 0 !important;
}

#course-list > li {
    display: flex !important;
    flex-direction: column !important;
    background: #fff !important;
    border-radius: 12px !important;
    overflow: hidden !important;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08) !important;
}

#course-list > li > div:first-child {
    width: 100% !important;
    height: 180px !important;
    min-height: 180px !important;
    max-height: 180px !important;
    overflow: hidden !important;
    position: relative !important;
    flex-shrink: 0 !important;
    background: #f0f0f0 !important;
}

#course-list img {
    width: 100% !important;
    height: 180px !important;
    min-height: 180px !important;
    max-height: 180px !important;
    object-fit: cover !important;
    display: block !important;
    flex-shrink: 0 !important;
    margin: 0 !important;
    padding: 0 !important;
}