/* ============================================================
   front_courses-0.0.1.css  — 课程/打卡/竞赛/Mind 统一样式
   基于 Bootstrap 3.3.7，火龙色系 #fa514c
   覆盖: /mind/course/*, /activity/daka/wx, /competition/groups, /mind/content|blog|problem|record/*
   响应式: 手机(<768) / 平板(768-991) / 电脑(>=992)
   ============================================================ */

/* ====== 通用 Tab 切换（Bootstrap nav-tabs 增强） ====== */
.grade-tabs {
    display: flex;
    border-bottom: 3px solid #f0f0f0;
    margin-bottom: 20px;
}
.grade-tabs a {
    flex: 1;
    text-align: center;
    padding: 12px 0;
    font-size: 15px;
    font-weight: 600;
    color: #999;
    text-decoration: none;
    border-bottom: 3px solid transparent;
    margin-bottom: -3px;
    transition: all .2s;
}
.grade-tabs a.active,
.grade-tabs a:hover { color: #fa514c; }
.grade-tabs a.active { border-bottom-color: #fa514c; }

.type-nav {
    display: flex;
    border-bottom: 3px solid #f0f0f0;
    margin-bottom: 16px;
}
.type-nav a {
    flex: 1;
    text-align: center;
    padding: 10px 0;
    font-size: 15px;
    font-weight: 600;
    color: #999;
    text-decoration: none;
    border-bottom: 3px solid transparent;
    margin-bottom: -3px;
    transition: all .2s;
}
.type-nav a.active,
.type-nav a:hover { color: #fa514c; }
.type-nav a.active { border-bottom-color: #fa514c; }

/* ====== 学年级卡片标签(数学课程) ====== */
.grade-card-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    margin: 20px 0;
}
.grade-card-tab {
    width: 100px;
    height: 80px;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 14px;
    font-weight: bold;
    color: #fff;
    border: 2px solid transparent;
    transition: all .2s;
    text-decoration: none;
    box-shadow: 0 2px 6px rgba(0,0,0,.1);
}
.grade-card-tab:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,.15);
}
.grade-card-tab.active {
    border-color: #333;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0,0,0,.2);
}
.grade-card-tab .grade-emoji { font-size: 26px; line-height: 1; }
.grade-card-tab .grade-label { font-size: 13px; margin-top: 2px; }
.grade-card-tab.grade-all { background: #fa514c; min-width: 90px; }
.grade-card-tab.grade-1   { background: #f093fb; }
.grade-card-tab.grade-2   { background: #4facfe; }
.grade-card-tab.grade-3   { background: #43e97b; }
.grade-card-tab.grade-4   { background: #fa709a; }
.grade-card-tab.grade-5   { background: #a18cd1; }
.grade-card-tab.grade-6   { background: #fcb69f; }

/* ====== 课程卡片 ====== */
.course-box { position: relative; margin-bottom: 20px; }
.course-card {
    border-radius: 8px;
    overflow: hidden;
    background: #fff;
    border: 1px solid #ddd;
    transition: all .3s;
    text-decoration: none;
    color: #333;
    display: block;
    box-shadow: 0 1px 4px rgba(0,0,0,.06);
}
.course-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 6px 16px rgba(0,0,0,.12);
    text-decoration: none;
}
.course-card .card-img {
    width: 100%;
    aspect-ratio: 16/10;
    object-fit: cover;
    display: block;
}
.course-card .card-body    { padding: 12px 14px; }
.course-card .card-title   { font-size: 15px; font-weight: 600; color: #333; margin: 0 0 6px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.course-card .card-subtitle{ font-size: 12px; color: #999; margin-bottom: 8px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.course-card .card-footer  { display: flex; justify-content: space-between; align-items: center; }
.course-card .price-tag    { font-size: 18px; font-weight: bold; color: #fa514c; }
.course-card .price-ori    { font-size: 12px; color: #bbb; text-decoration: line-through; margin-left: 6px; }
.course-card .grade-badge  { position: absolute; top: 10px; right: 10px; background: rgba(0,0,0,.55); color: #fff; font-size: 11px; padding: 2px 8px; border-radius: 10px; font-weight: 500; }
.course-card .join-btn     { font-size: 12px; padding: 4px 12px; border-radius: 14px; background: #fa514c; color: #fff; border: none; cursor: pointer; font-weight: 500; }
.course-card .joined-btn   { background: #5cb85c; cursor: default; }

/* ====== 置顶按钮 ====== */
.course-box .top-btn {
    display: none;
    position: absolute;
    z-index: 2;
    border: none;
    background: rgba(255,255,255,.92);
    color: #fa514c;
    font-size: 12px;
    cursor: pointer;
    border-radius: 4px;
    padding: 2px 6px;
    left: 8px;
    top: 8px;
}
.course-box:hover .top-btn { display: block; }
.top-btn:hover  { background: #fce4e4; }
.top-btn.active { background: #fa514c; color: #fff; }
.course-box .top-btn-right { right: 10px; top: 10px; left: auto; font-size: 14px; }

/* ====== 打卡活动条目 ====== */
.act-item {
    display: flex;
    gap: 16px;
    padding: 20px;
    margin-bottom: 16px;
    border: 1px solid #ddd;
    border-radius: 4px;
    transition: box-shadow .2s;
}
.act-item:hover { box-shadow: 0 2px 12px rgba(0,0,0,.08); }
.act-main      { flex: 1; min-width: 0; }
.act-top       { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.act-title     { font-size: 19px; font-weight: 600; color: #333; line-height: 1.3; }
.act-title a   { color: #333; text-decoration: none; }
.act-title a:hover { color: #fa514c; }
.act-desc      { font-size: 14px; color: #666; margin: 10px 0; line-height: 1.6; }
.act-bottom    { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 8px; }
.act-meta      { font-size: 13px; color: #999; display: flex; gap: 24px; }
.act-price     { text-align: right; display: flex; align-items: center; gap: 8px; }

.act-tags   { display: flex; gap: 6px; flex-shrink: 0; }
.tag-status { font-size: 12px; padding: 2px 10px; border-radius: 3px; font-weight: 500; }
.tag-ongoing{ background: #e6f7ff; color: #1890ff; border: 1px solid #91d5ff; }
.tag-joined { background: #f6ffed; color: #5cb85c; border: 1px solid #b7eb8f; }
.tag-grade  { font-size: 12px; padding: 2px 10px; border-radius: 3px; font-weight: 500; color: #fff; }
.tag-gesp   { background: #1890ff; }
.tag-csp    { background: #5cb85c; }
.tag-math   { background: #fa514c; }

.price-ori   { font-size: 13px; color: #bbb; text-decoration: line-through; }
.price-now   { font-size: 22px; font-weight: 800; color: #fa514c; }
.price-now small { font-size: 13px; font-weight: 500; color: #fa514c; }
.price-free  { font-size: 16px; font-weight: 600; color: #5cb85c; }

/* ====== 竞赛团队卡片 ====== */
.team-card { min-height: 80px; cursor: pointer; }
.card-header2 {
    margin-bottom: 0;
    color: #fff;
    background: linear-gradient(135deg, #fa514c, #ff7875);
    border-bottom: 1px solid rgba(0,0,0,.125);
}
.team-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #999;
    font-size: 14px;
    margin: 10px;
}
.team-footer .team-member { white-space: nowrap; }
.team-footer .team-author img {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    margin-right: 6px;
}

/* ====== 数学页面标题渐变 ====== */
.page-header-gradient {
    text-align: center;
    font-size: 26px;
    font-weight: bold;
    margin: 10px 0 0;
    background: linear-gradient(135deg, #fa514c, #ff9a56, #ff6b6b);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ====== Mind 课程页共用 ====== */
.file-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 20px;
    background-color: #f5f5f5;
    border-radius: 4px;
}
.mind-resource-file-item {
    padding: 15px;
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-shadow: 0 1px 3px rgba(0,0,0,.08);
    transition: background-color .3s, transform .3s;
}
.mind-resource-file-item:hover { background-color: #f5f5f5; transform: translateY(-2px); }
.file-link { text-decoration: none; color: #fa514c; font-weight: bold; font-size: 16px; }
.file-link:hover { text-decoration: underline; color: #e04843; }
.feedback-textarea {
    width: 100%; height: 150px; padding: 10px; font-size: 14px;
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; color: #333;
    border: 1px solid #ccc; border-radius: 4px;
    background-color: #eee; resize: none;
    box-shadow: inset 0 1px 3px rgba(0,0,0,.1);
}
.notice { margin: 20px 0; font-size: 14px; color: #333; }
.mind-table-wrap { width: 100%; overflow-x: auto; -webkit-overflow-scrolling: touch; }
.mind-table-wrap table { min-width: 600px; }


/* ================================================================
   响应式: 手机 (< 768px)
   ================================================================ */
@media (max-width: 767px) {
    .grade-tabs a     { font-size: 13px; padding: 8px 0; }
    .grade-card-tabs  { gap: 6px; }
    .grade-card-tab   { width: 70px; height: 62px; font-size: 12px; border-radius: 6px; }
    .grade-card-tab .grade-emoji { font-size: 20px; }
    .grade-card-tab .grade-label { font-size: 11px; }

    .course-box                   { margin-bottom: 12px; }
    .course-box dl                { margin-bottom: 0; }
    .course-box .name p           { font-size: 13px; }
    .course-box .price .present-price { font-size: 13px; }
    .course-box .price .original-price{ font-size: 11px; }
    .course-box .go button        { font-size: 11px; padding: 3px 8px; }
    .course-card .card-title      { font-size: 13px; }
    .course-card .card-subtitle   { font-size: 11px; }
    .course-card .card-body       { padding: 8px 10px; }
    .course-card .price-tag       { font-size: 14px; }
    .course-card .price-ori       { font-size: 10px; }

    .act-item      { flex-direction: column; gap: 12px; padding: 14px; }
    .act-top       { flex-direction: column; gap: 6px; }
    .act-title     { font-size: 16px; }
    .act-desc      { font-size: 13px; }
    .act-meta      { font-size: 12px; gap: 16px; }
    .price-now     { font-size: 19px; }

    .card-header2  { font-size: 14px; padding: 8px 10px; }
    .team-card .card-body, .team-card .panel-body { padding: 8px 10px; }
    .team-footer   { font-size: 12px; }
    .team-card     { margin-bottom: 10px; }

    .page-header-gradient { font-size: 20px; }

    .file-list               { padding: 10px; gap: 6px; }
    .mind-resource-file-item { padding: 10px; }
    .file-link               { font-size: 14px; }
    .feedback-textarea       { height: 100px; font-size: 13px; }
    .notice                  { font-size: 13px; margin: 10px 0; }
}


/* ================================================================
   响应式: 平板 (768px ~ 991px)
   ================================================================ */
@media (min-width: 768px) and (max-width: 991px) {
    .grade-card-tab { width: 85px; height: 70px; }
    .act-title      { font-size: 17px; }
    .price-now      { font-size: 20px; }
}