:root{--ink:#243343;--soft:#657588;--accent:#2c826c;--accent-dark:#236956;--bg:#fafbf9;--line:#e7ebe9;--cream:#f1f6ed;--white:#fff;--blue:#26374c;--shadow:0 12px 36px rgba(30,49,58,.05)}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.65 -apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif}h1,h2,h3,p{margin:0}h1,h2,h3{line-height:1.32;letter-spacing:-.025em}a{color:inherit;text-decoration:none}button,input,select,textarea{font:inherit}button{cursor:pointer}img{max-width:100%}.container{width:min(1140px,calc(100% - 40px));margin:auto}.topbar{height:74px;border-bottom:1px solid var(--line);background:rgba(255,255,255,.94)}.nav{height:100%;display:flex;justify-content:space-between;align-items:center}.brand{font-weight:750;font-size:18px;display:flex;align-items:center;gap:11px;white-space:nowrap}.brand-symbol{width:35px;height:35px;border-radius:10px;background:var(--accent);color:white;display:inline-grid;place-items:center;font-size:19px;font-family:serif}.nav-links{display:flex;align-items:center;gap:32px;color:#536476;font-size:14px}.nav-links a:hover{color:var(--accent)}.nav-links .admin-link{color:#85928c}.hero{background:linear-gradient(110deg,#f1f6eb 10%,#f8faf7 55%,#eff7f4 100%);border-bottom:1px solid #e5ebe4;padding:76px 0 67px}.eyebrow{text-transform:uppercase;font-size:12px;color:var(--accent);font-weight:750;letter-spacing:.13em;margin-bottom:11px}.hero h1{font-size:clamp(34px,5vw,54px);font-weight:800;margin-bottom:16px}.accent{color:var(--accent)}.hero-sub{font-size:16px;color:#647783;max-width:650px;line-height:1.85}.hero-search{display:flex;align-items:center;gap:12px;margin-top:30px;width:min(740px,100%);background:white;padding:8px 8px 8px 20px;border:1px solid #e1e8df;border-radius:13px;box-shadow:var(--shadow)}.hero-search svg{color:#819085;flex:none}.hero-search input{flex:1;min-width:0;border:0;outline:0;color:var(--ink);font-size:15px}.btn{display:inline-flex;align-items:center;justify-content:center;border:1px solid transparent;border-radius:9px;min-height:41px;padding:8px 18px;font-size:14px;font-weight:680;white-space:nowrap;transition:background .15s ease,transform .15s ease}.btn:hover{transform:translateY(-1px)}.btn:disabled{opacity:.55;cursor:not-allowed}.btn-primary{color:white;background:var(--accent)}.btn-primary:hover{background:var(--accent-dark)}.btn-dark{background:var(--blue);color:white}.btn-ghost{border-color:var(--line);background:white;color:var(--soft)}.wide{width:100%}.hero-tags{margin-top:20px;display:flex;gap:14px;align-items:center;flex-wrap:wrap;font-size:13px;color:#7e8b89}.hero-tags a{color:var(--accent);background:#e4f1e8;padding:3px 12px;border-radius:40px}.listing{padding-top:64px;padding-bottom:68px}.section-head{display:flex;justify-content:space-between;align-items:end;margin-bottom:24px}.section-head h2{font-size:27px}.muted{color:var(--soft)}.small{font-size:13px}.tiny{font-size:12px}.filters{display:flex;flex-wrap:wrap;gap:12px;align-items:end;margin-bottom:28px}.filters label{display:flex;flex-direction:column;gap:5px;font-size:12px;color:#778596}.filters select,.admin-main input,.admin-main textarea,.admin-main select,.edit-fields input,.edit-fields textarea,.edit-fields select{border:1px solid #dae2e3;border-radius:9px;padding:10px 12px;background:white;color:var(--ink);min-width:138px;outline-color:var(--accent)}.filters select{min-height:41px}.course-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:23px}.course-card{border:1px solid #e7ebe9;background:white;border-radius:15px;overflow:hidden;box-shadow:var(--shadow);transition:transform .2s,box-shadow .2s}.course-card:hover{transform:translateY(-4px);box-shadow:0 20px 40px rgba(27,54,45,.11)}.card-cover{height:auto;aspect-ratio:16/9;background:#dfeae4;position:relative}.card-cover img{display:block;width:100%;height:100%;object-fit:cover}.corner-label{position:absolute;top:13px;left:13px;background:rgba(255,255,255,.9);color:#49675e;font-size:11px;padding:3px 10px;border-radius:6px}.cover-fallback{width:100%;height:100%;padding:34px;background:linear-gradient(130deg,#315b5b,#839a7b);display:flex;flex-direction:column;justify-content:center;color:white}.cover-fallback span{font-size:12px;letter-spacing:.15em;opacity:.75}.cover-fallback strong{font-family:serif;font-size:21px;margin-top:10px}.card-body{padding:20px}.course-meta{color:var(--accent);font-size:12px;letter-spacing:.015em;font-weight:700}.card-body h3{font-size:18px;font-weight:700;margin-top:8px;margin-bottom:15px;min-height:46px}.chips,.detail-tags{display:flex;flex-wrap:wrap;gap:7px}.chips span,.detail-tags span{font-size:11px;padding:3px 9px;border-radius:5px;background:#f1f5f2;color:#597369}.card-link{font-size:13px;color:var(--accent);display:flex;justify-content:space-between;margin-top:23px;font-weight:650;border-top:1px solid #eff2ef;padding-top:12px}.empty-state{background:white;border:1px solid var(--line);border-radius:16px;text-align:center;padding:80px 20px}.empty-icon{font-size:44px;color:var(--accent)}.empty-state h3{font-size:21px;margin:5px 0}.empty-state p{color:var(--soft);margin-bottom:20px}.cta-panel{background:var(--cream);border:1px solid #e3ebdf;border-radius:16px;padding:32px 42px;margin-bottom:70px;display:flex;gap:24px;align-items:center;justify-content:space-between}.cta-panel h2{font-size:25px;margin-bottom:8px}.cta-panel p:not(.eyebrow){color:var(--soft)}.site-footer{border-top:1px solid var(--line);padding:28px 0;color:#849095;font-size:12px}.footer-inner{display:flex;justify-content:space-between;gap:18px}.detail-wrap{padding:24px 0 80px}.crumbs{display:flex;gap:10px;align-items:center;color:#85919c;font-size:12px;margin:6px 0 30px;flex-wrap:wrap}.crumbs a:hover{color:var(--accent)}.detail-grid{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:40px;align-items:start}.detail-top h1{font-size:36px;margin:10px 0 14px}.detail-desc{font-size:15px;line-height:1.95;color:#687a89;margin-bottom:18px}.detail-tags{margin-bottom:35px}.detail-tags span{font-size:12px;padding:5px 12px}.preview-area{padding:27px;background:white;border:1px solid var(--line);border-radius:15px}.preview-area .section-head{margin-bottom:19px}.preview-area h2{font-size:22px}.preview-big,.preview-sheet{display:block;background:#f5f7f6;border:1px solid var(--line);border-radius:10px;overflow:hidden;margin:12px 0;position:relative}.preview-big img,.preview-sheet img{display:block;width:100%;object-fit:contain;max-height:690px}.image-hint{position:absolute;bottom:12px;right:12px;padding:4px 12px;background:rgba(255,255,255,.88);border-radius:7px;font-size:12px}.preview-sheet span{display:block;font-size:12px;padding:9px 12px;color:var(--soft)}.preview-note{margin-top:15px;font-size:12px}.preview-placeholder{padding:60px 15px;background:#f1f3f2;text-align:center;color:var(--soft)}.detail-aside{position:sticky;top:30px}.consult-box,.tips-box{background:white;border:1px solid var(--line);border-radius:13px;padding:25px;box-shadow:var(--shadow);margin-bottom:18px}.consult-box h3{font-size:22px;margin-bottom:10px}.consult-box p:not(.eyebrow){color:var(--soft);font-size:13px;line-height:1.8;margin-bottom:16px}.consult-box .wechat-qr{width:178px;height:178px;object-fit:contain;display:block;margin:20px auto}.wechat-id{background:#f3f7f4;color:#45665d;font-size:13px;padding:10px;margin:14px 0;border-radius:8px;word-break:break-all}.consult-box p.tiny{margin-top:15px}.tips-box strong{display:block;margin-bottom:12px}.tips-box p{color:var(--soft);font-size:13px;margin-top:7px}.related{margin-top:42px}.related h2{font-size:22px;margin-bottom:18px}.related-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.related-grid a{display:flex;flex-direction:column;gap:7px;padding:19px;background:white;border:1px solid var(--line);border-radius:10px}.related-grid a strong{font-size:14px}.related-grid a span{font-size:12px;color:var(--accent)}.notice{background:#eff6f2;border:1px solid #d8e9df;color:#49735f;border-radius:9px;padding:12px;font-size:13px;margin-top:12px}
/* 后台 */
.admin-body{background:#f4f6f8}.login-shell{display:grid;min-height:100vh;place-items:center;padding:24px}.login-card{background:white;border:1px solid #e5e8eb;border-radius:18px;padding:40px;width:min(425px,100%);box-shadow:0 18px 65px rgba(27,39,53,.08)}.login-card h1{margin:30px 0 7px;font-size:29px}.login-card .muted{margin-bottom:23px}.login-card input{display:block;width:100%;margin:15px 0;padding:12px;border:1px solid #dce2e5;border-radius:9px}.login-card .small{display:block;margin-top:20px}.error{color:#c75047;font-size:13px;margin:10px 0}.dashboard{min-height:100vh;display:grid;grid-template-columns:230px minmax(0,1fr)}.sidebar{background:#192c33;color:#eaf1ee;padding:25px 20px;display:flex;flex-direction:column}.sidebar .brand{font-size:17px;margin-bottom:45px}.sidebar nav{display:flex;flex-direction:column;gap:5px}.sidebar nav a{padding:11px 14px;border-radius:8px;color:#b9cac7;font-size:14px}.sidebar nav a:hover,.sidebar nav a.active{background:#2c464a;color:white}.sidebar #logout{margin-top:auto;background:transparent;color:#b9cac7;border-color:#456064}.admin-main{padding:42px min(4vw,56px) 65px;min-width:0}.admin-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:28px}.admin-head h1{font-size:30px}.admin-local{font-size:12px;background:#e8f2eb;color:#46775d;border-radius:30px;padding:5px 14px}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-bottom:24px}.stats>div{background:white;border:1px solid #e5e9eb;border-radius:12px;padding:23px}.stats strong{font-size:32px;display:block;color:#243843}.stats span{font-size:12px;color:#849093}.panel{background:white;border:1px solid #e5e9eb;border-radius:13px;padding:25px;box-shadow:var(--shadow)}.panel h2{font-size:21px}.panel-head{display:flex;justify-content:space-between;align-items:center;gap:15px;margin-bottom:20px}.row-tools{display:flex;gap:10px}.row-tools input{min-width:210px}.table-scroll{overflow-x:auto}.data-table{width:100%;border-collapse:collapse;white-space:nowrap;text-align:left}.data-table th{font-size:12px;color:#8b969f;background:#f7f9fa;font-weight:550;padding:14px 12px}.data-table td{padding:15px 12px;font-size:13px;border-bottom:1px solid #edf0f1;max-width:370px;overflow:hidden;text-overflow:ellipsis}.status{border-radius:30px;padding:5px 10px;font-size:11px}.status-live{background:#e7f4ec;color:#267250}.status-draft{background:#f2f3f4;color:#7f8994}.action-link{color:var(--accent);border:0;background:transparent;font-weight:700}.warn{color:#b17533;font-size:12px}.good{color:#39876d;font-size:12px}.import-panel>p:not(.eyebrow){margin-top:12px;color:var(--soft);font-size:14px;max-width:750px}.import-panel code{background:#eef2f4;border-radius:4px;padding:2px 5px}.upload-area{margin:25px 0;padding:50px 20px;background:#f8faf8;border:2px dashed #cadbd1;border-radius:12px;display:flex;flex-direction:column;align-items:center;text-align:center;gap:12px}.upload-icon{font-size:43px;color:var(--accent)}.upload-area p{font-size:12px;color:var(--soft)}.upload-area input{max-width:100%;border:0}.explain{background:#f4f7f5;padding:20px;border-radius:9px}.explain h3{font-size:16px}.explain p{font-size:13px;color:var(--soft);margin-top:8px}.settings-panel{max-width:700px}.settings-panel label,.edit-fields label{display:flex;flex-direction:column;gap:7px;color:#5a6974;font-size:13px;margin-top:17px}.settings-panel label input{width:100%}.settings-panel .btn{margin-top:22px}.settings-panel hr{border:0;border-top:1px solid var(--line);margin:32px 0}.settings-panel h3{font-size:18px}.settings-panel p{margin-top:9px}.settings-panel input[type=file]{display:block;margin:15px 0}.settings-qr{width:170px;display:block;margin-top:22px;border:1px solid var(--line);border-radius:7px}.edit-dialog{width:min(670px,calc(100% - 20px));max-height:90vh;overflow:auto;border:1px solid #e5e9eb;border-radius:14px;box-shadow:0 25px 100px rgba(0,0,0,.22);padding:0}.edit-dialog::backdrop{background:rgba(19,35,44,.55)}.edit-header,.dialog-footer{padding:18px 24px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}.dialog-footer{border-top:1px solid var(--line);border-bottom:0;justify-content:end;gap:10px}.edit-header h2{font-size:21px}.icon-button{background:transparent;border:0;font-size:28px;color:var(--soft)}.edit-fields{padding:4px 25px 20px}.edit-fields input,.edit-fields select,.edit-fields textarea{width:100%}.two-fields{display:grid;grid-template-columns:1fr 1fr;gap:16px}.editor-preview img{margin-top:14px;border-radius:8px;max-width:290px;display:block}.toast{position:fixed;bottom:26px;right:26px;padding:13px 20px;border-radius:9px;background:#243943;color:white;box-shadow:var(--shadow);z-index:1000;font-size:14px}
@media(max-width:900px){.course-grid{grid-template-columns:repeat(2,1fr)}.detail-grid{grid-template-columns:1fr}.detail-aside{position:static}.dashboard{grid-template-columns:1fr}.sidebar{padding:15px 24px}.sidebar nav{flex-direction:row;flex-wrap:wrap}.sidebar .brand{margin-bottom:15px}.sidebar #logout{margin-top:10px;align-self:flex-start}.admin-main{padding:26px}.admin-local{display:none}}@media(max-width:600px){.container{width:min(100% - 28px,1140px)}.topbar{height:64px}.nav-links{gap:13px;font-size:12px}.nav-links .admin-link{display:none}.brand{font-size:15px}.hero{padding:51px 0}.hero h1{font-size:35px}.hero-search{flex-wrap:wrap;padding:12px}.hero-search input{width:calc(100% - 35px);flex:auto;font-size:13px}.hero-search .btn{width:100%}.course-grid{grid-template-columns:1fr}.filters{display:grid;grid-template-columns:repeat(2,1fr)}.filters label select{width:100%}.section-head h2{font-size:23px}.cta-panel{padding:24px;display:block}.cta-panel .btn{margin-top:20px}.footer-inner{flex-direction:column}.detail-top h1{font-size:29px}.preview-area{padding:15px}.related-grid{grid-template-columns:1fr}.stats{grid-template-columns:repeat(3,1fr);gap:7px}.stats>div{padding:13px}.stats strong{font-size:24px}.stats span{font-size:11px}.panel{padding:14px}.panel-head{align-items:stretch;flex-direction:column}.row-tools{flex-direction:column}.row-tools input{width:100%}.admin-main{padding:20px 12px}.two-fields{grid-template-columns:1fr}}
/* 图库版本增强 */
.full-poster{display:block;border:1px solid #e4e8e7;background:#f7f9f8;border-radius:12px;overflow:hidden;text-decoration:none}
.full-poster img{display:block;width:100%;height:auto;max-height:none;object-fit:contain}
.full-poster span{display:block;text-align:center;color:#6f8285;font-size:12px;padding:12px 8px;background:#fafcfb}
.card-cover img{object-position:top center}
.upload-form-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:24px}
.upload-form-grid label,.inline-title{display:flex;flex-direction:column;gap:9px;font-size:13px;color:#586a72}
.upload-form-grid select,.inline-title input{width:100%;padding:11px;border:1px solid #d7dfe0;border-radius:8px}
.inline-title{text-align:left;width:min(440px,100%);margin:10px auto}
.share-row{display:flex;gap:10px;margin-top:18px}
.share-row input{flex:1;min-width:0}
.danger{color:#a22e2e!important;margin-right:auto}
.btn-outline{border:1px solid #bccdc5!important;background:white!important;color:#346755!important}
.share-link{margin-top:10px}
@media(max-width:600px){.upload-form-grid{grid-template-columns:1fr}.share-row{flex-direction:column}}
[hidden]{display:none!important}

/* Course manager grouped by grade */
.course-tools{align-items:flex-end;flex-wrap:wrap}.grade-filter{display:flex;flex-direction:column;gap:5px;color:#778596;font-size:12px}.grade-filter select{min-width:130px}.course-grade-groups{display:grid;gap:12px}.course-grade-group{overflow:hidden;border:1px solid #e2e8e8;border-radius:12px;background:#fff}.course-grade-group[open]{box-shadow:0 8px 24px rgba(30,49,58,.045)}.course-grade-summary{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:15px 18px;background:#f8faf9;cursor:pointer;list-style:none}.course-grade-summary::-webkit-details-marker{display:none}.course-grade-name,.course-grade-counts{display:flex;align-items:center;gap:12px}.course-grade-name strong{font-size:16px}.course-grade-name span,.course-grade-counts{font-size:12px;color:#73827f}.course-grade-counts{gap:16px}.course-grade-toggle{color:#2c826c}.course-grade-group[open] .course-grade-summary{border-bottom:1px solid #edf0ef;background:#f2f7f4}.course-grade-group .table-scroll{padding:0 12px 8px}.course-grade-group .data-table th{background:#fff}.course-groups-empty{padding:28px 12px;text-align:center}.category-help{margin:8px 0 12px;color:#72817f;font-size:12px}
@media(max-width:700px){.course-grade-summary{align-items:flex-start;flex-direction:column}.course-grade-counts{flex-wrap:wrap;gap:8px 14px}.course-grade-group .data-table{min-width:640px}.course-tools{display:grid;grid-template-columns:1fr}.grade-filter select{width:100%}}
.course-row-thumb{display:block;width:58px;height:70px;object-fit:cover;object-position:top center;border:1px solid #e4e9e7;border-radius:6px;background:#f1f4f2}.data-table td:has(.course-row-thumb){width:82px;max-width:82px}.row-delete{color:#b04444}.row-delete:hover{color:#8e2525;text-decoration:underline}.editor-preview{display:flex;align-items:center;gap:16px;flex-wrap:wrap;margin-top:16px}.editor-preview figure{margin:0}.editor-preview img{display:block;margin:0 0 5px!important;width:180px;height:220px;max-width:min(180px,38vw);max-height:220px;object-fit:cover;object-position:top center;border-radius:8px;background:#f2f5f4}.editor-preview figcaption{font-size:12px;color:#75827f}.editor-full-link{align-self:center;color:var(--accent);font-weight:650;font-size:13px}.editor-full-link:hover{text-decoration:underline}
.pagination{display:flex;justify-content:center;align-items:center;gap:16px;margin:30px 0 6px;color:var(--soft);font-size:13px}.pagination .btn{min-width:88px}