/* ============================================================
   井天乐的学习站 — base stylesheet
   White-based, dark-green (墨绿) theme. All colors/fonts via CSS
   variables injected from config (env-overridable). No gradients,
   no emoji. Serif headings, sans body.
   ============================================================ */

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:var(--font-sans);
  background:var(--bg);
  color:var(--ink);
  font-size:16px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4,h5{font-family:var(--font-serif);font-weight:700;line-height:1.3;color:var(--ink)}
h1{font-size:1.9rem;letter-spacing:-.01em}
h2{font-size:1.5rem;margin:2rem 0 .8rem}
h3{font-size:1.2rem;margin:1.5rem 0 .6rem}
h4{font-size:1.05rem;margin:1.2rem 0 .5rem}
a{color:var(--primary);text-decoration:none;transition:color .15s}
a:hover{color:var(--primary-dark)}
p{margin:.6rem 0}
img{max-width:100%;height:auto}
code,pre{font-family:var(--font-mono);font-size:.88em}
code{background:var(--bg3);padding:.1em .35em;border-radius:4px}
pre{background:var(--bg2);border:1px solid var(--rule);border-radius:var(--radius);padding:1rem;overflow-x:auto;line-height:1.55}
pre code{background:none;padding:0}
blockquote{border-left:3px solid var(--primary-soft);padding:.3rem 1rem;color:var(--muted);margin:1rem 0;background:var(--bg2)}
hr{border:none;border-top:1px solid var(--rule);margin:2rem 0}

/* layout */
.container{max-width:1100px;margin:0 auto;padding:0 1.25rem}
.wrap{min-height:100vh;display:flex;flex-direction:column}

/* header / nav */
.site-header{
  background:var(--bg);
  border-bottom:1px solid var(--rule);
  position:sticky;top:0;z-index:50;
}
.site-header .inner{
  max-width:1100px;margin:0 auto;padding:0 1.25rem;
  display:flex;align-items:center;gap:1.5rem;height:60px;
}
.brand{display:flex;align-items:center;gap:.6rem;color:var(--primary);font-weight:700;font-family:var(--font-serif);font-size:1.15rem}
.brand svg{color:var(--primary)}
.nav{display:flex;gap:.2rem;flex:1;margin-left:.5rem}
.nav a{
  display:flex;align-items:center;gap:.4rem;
  padding:.5rem .8rem;border-radius:var(--radius);
  color:var(--ink);font-size:.95rem;font-weight:500;
}
.nav a:hover{background:var(--primary-soft);color:var(--primary-dark)}
.nav a.active{background:var(--primary-soft);color:var(--primary-dark)}
.nav a svg{width:18px;height:18px}
.nav-search{display:flex;align-items:center;gap:.4rem}
.nav-search input{
  border:1px solid var(--rule);border-radius:999px;
  padding:.35rem .9rem;font-size:.88rem;width:160px;
  font-family:var(--font-sans);background:var(--bg2);color:var(--ink);
  transition:border-color .15s,width .15s;
}
.nav-search input:focus{outline:none;border-color:var(--primary);width:200px;background:var(--bg)}
.nav-search button{background:none;border:none;color:var(--muted);cursor:pointer;display:flex;padding:4px}
.menu-toggle{display:none;background:none;border:none;color:var(--ink);cursor:pointer;padding:6px}

/* footer */
.site-footer{
  margin-top:auto;border-top:1px solid var(--rule);
  background:var(--bg2);color:var(--muted);font-size:.85rem;
}
.site-footer .inner{max-width:1100px;margin:0 auto;padding:1.5rem 1.25rem;display:flex;justify-content:space-between;flex-wrap:wrap;gap:1rem}
.site-footer a{color:var(--muted)}
.site-footer a:hover{color:var(--primary)}

/* buttons */
.btn{
  display:inline-flex;align-items:center;gap:.4rem;
  padding:.55rem 1.1rem;border-radius:var(--radius);
  font-size:.92rem;font-weight:600;font-family:var(--font-sans);
  border:1px solid var(--primary);background:var(--primary);color:#fff;
  cursor:pointer;transition:background .15s,border-color .15s;
  text-decoration:none;
}
.btn:hover{background:var(--primary-dark);border-color:var(--primary-dark);color:#fff}
.btn svg{width:18px;height:18px}
.btn.ghost{background:transparent;color:var(--primary)}
.btn.ghost:hover{background:var(--primary-soft);color:var(--primary-dark)}
.btn.sm{padding:.35rem .7rem;font-size:.82rem}
.btn.danger{background:#b91c1c;border-color:#b91c1c}
.btn.danger:hover{background:#991b1b;border-color:#991b1b}

/* cards grid */
.grid{display:grid;gap:1.2rem}
.grid.cols-2{grid-template-columns:repeat(2,1fr)}
.grid.cols-3{grid-template-columns:repeat(3,1fr)}
.grid.cols-4{grid-template-columns:repeat(4,1fr)}

.card{
  background:var(--bg);border:1px solid var(--rule);border-radius:var(--radius);
  padding:1.2rem;transition:border-color .15s,box-shadow .15s;display:flex;flex-direction:column;
}
.card:hover{border-color:var(--primary);box-shadow:0 2px 12px rgba(27,94,63,.08)}
.card .card-icon{
  width:44px;height:44px;display:flex;align-items:center;justify-content:center;
  border-radius:10px;background:var(--primary-soft);color:var(--primary);margin-bottom:.8rem;
}
.card .card-icon svg{width:24px;height:24px}
.card h3{margin:0 0 .4rem;font-size:1.1rem}
.card .desc{color:var(--muted);font-size:.9rem;flex:1}
.card .meta{margin-top:.8rem;font-size:.8rem;color:var(--muted);display:flex;gap:1rem;flex-wrap:wrap}
.card .meta span{display:inline-flex;align-items:center;gap:.25rem}
.card .meta svg{width:14px;height:14px}

/* tiles (learning pages) */
.tile{
  position:relative;display:block;
  background:var(--bg);border:1px solid var(--rule);border-radius:var(--radius);
  padding:1.5rem;overflow:hidden;transition:transform .15s,box-shadow .15s,border-color .15s;
  min-height:140px;
}
.tile:hover{transform:translateY(-3px);box-shadow:0 6px 20px rgba(0,0,0,.08);border-color:var(--primary)}
.tile .tile-icon{width:40px;height:40px;margin-bottom:.8rem}
.tile .tile-bar{position:absolute;left:0;top:0;bottom:0;width:4px;background:var(--primary)}
.tile.pinned .tile-bar{background:var(--accent)}
.tile h3{margin:0 0 .3rem}
.tile p{color:var(--muted);font-size:.9rem;margin:0}

/* section title */
.section-head{display:flex;align-items:center;justify-content:space-between;margin:2.5rem 0 1.2rem}
.section-head h2{margin:0;display:flex;align-items:center;gap:.5rem}
.section-head h2 svg{width:22px;height:22px;color:var(--primary)}
.section-head .more{font-size:.88rem;color:var(--muted)}
.section-head .more:hover{color:var(--primary)}

/* page hero */
.hero{padding:2.5rem 0 1rem}
.hero h1{font-size:2.2rem;margin-bottom:.5rem}
.hero p{color:var(--muted);font-size:1.05rem;max-width:640px}

/* search bar (full) */
.searchbar{display:flex;gap:.5rem;margin:1.5rem 0}
.searchbar input{
  flex:1;border:1px solid var(--rule);border-radius:var(--radius);
  padding:.7rem 1rem;font-size:1rem;font-family:var(--font-sans);background:var(--bg);color:var(--ink);
}
.searchbar input:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-soft)}

/* sidebar filter */
.layout-2col{display:grid;grid-template-columns:220px 1fr;gap:2rem;margin:1.5rem 0}
.filter-side{position:sticky;top:80px;align-self:start}
.filter-side h4{font-size:.85rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin-bottom:.6rem}
.filter-side ul{list-style:none}
.filter-side li{margin:.15rem 0}
.filter-side a{display:block;padding:.35rem .6rem;border-radius:6px;font-size:.92rem;color:var(--ink)}
.filter-side a:hover{background:var(--primary-soft);color:var(--primary-dark)}
.filter-side a.active{background:var(--primary);color:#fff}

/* material list item */
.mat-item{
  display:flex;gap:1rem;align-items:flex-start;
  background:var(--bg);border:1px solid var(--rule);border-radius:var(--radius);
  padding:1rem 1.2rem;margin-bottom:.8rem;transition:border-color .15s;
}
.mat-item:hover{border-color:var(--primary)}
.mat-item .mat-icon{
  flex-shrink:0;width:42px;height:42px;border-radius:8px;
  background:var(--primary-soft);color:var(--primary);
  display:flex;align-items:center;justify-content:center;
}
.mat-item .mat-body{flex:1;min-width:0}
.mat-item .mat-body h3{margin:0 0 .25rem;font-size:1.05rem}
.mat-item .mat-body .desc{color:var(--muted);font-size:.88rem;margin-bottom:.4rem}
.mat-item .mat-tags{display:flex;gap:.4rem;flex-wrap:wrap}
.tag-chip{
  font-size:.76rem;background:var(--bg3);color:var(--muted);
  padding:.1rem .5rem;border-radius:999px;
}
.tag-chip.subject{background:var(--primary-soft);color:var(--primary-dark)}
.mat-actions{display:flex;gap:.5rem;flex-shrink:0;align-self:center}

/* pagination */
.pager{display:flex;gap:.3rem;justify-content:center;margin:2rem 0;flex-wrap:wrap}
.pager a,.pager span{
  min-width:36px;height:36px;display:flex;align-items:center;justify-content:center;
  border:1px solid var(--rule);border-radius:6px;font-size:.9rem;padding:0 .5rem;
}
.pager a:hover{border-color:var(--primary);color:var(--primary)}
.pager .cur{background:var(--primary);color:#fff;border-color:var(--primary)}
.pager .gap{border:none}

/* article / blog */
.article{max-width:760px;margin:0 auto}
.article-head{margin-bottom:1.5rem;border-bottom:1px solid var(--rule);padding-bottom:1.2rem}
.article-head .meta{color:var(--muted);font-size:.88rem;display:flex;gap:1rem;flex-wrap:wrap;margin-top:.5rem}
.article-head .meta span{display:inline-flex;align-items:center;gap:.3rem}
.article-head .meta svg{width:15px;height:15px}
.article-body{font-size:1.02rem;line-height:1.85}
.article-body h2{margin-top:2rem}
.article-body h3{margin-top:1.5rem}
.article-body p{margin:.8rem 0}
.article-body img{border-radius:var(--radius);margin:1rem 0}
.article-body ul,.article-body ol{padding-left:1.5rem;margin:.8rem 0}
.article-body li{margin:.3rem 0}
.article-body code{font-size:.85em}
.article-body pre{margin:1rem 0}
.article-body table{width:100%;border-collapse:collapse;margin:1rem 0;font-size:.92rem}
.article-body th,.article-body td{border:1px solid var(--rule);padding:.5rem .7rem;text-align:left}
.article-body th{background:var(--bg2);font-weight:700}

/* blog list */
.post-card{
  display:flex;gap:1.2rem;background:var(--bg);border:1px solid var(--rule);
  border-radius:var(--radius);padding:1.2rem;margin-bottom:1rem;transition:border-color .15s;
}
.post-card:hover{border-color:var(--primary)}
.post-card .cover{flex-shrink:0;width:140px;height:90px;border-radius:6px;background:var(--primary-soft);object-fit:cover}
.post-card .body{flex:1;min-width:0}
.post-card h3{margin:0 0 .3rem;font-size:1.15rem}
.post-card .summary{color:var(--muted);font-size:.9rem;margin:.3rem 0 .5rem}
.post-card .meta{font-size:.8rem;color:var(--muted);display:flex;gap:1rem}
.post-card .meta svg{width:14px;height:14px}

/* preview frame */
.preview-wrap{background:var(--bg2);border:1px solid var(--rule);border-radius:var(--radius);overflow:hidden}
.preview-toolbar{display:flex;align-items:center;gap:1rem;padding:.6rem 1rem;background:var(--bg3);border-bottom:1px solid var(--rule);font-size:.85rem;color:var(--muted)}
.preview-toolbar .filename{font-family:var(--font-mono);font-size:.82rem}
.preview-frame{height:75vh;width:100%;border:none;background:#fff;display:block}

/* forms */
.form-group{margin-bottom:1rem}
.form-group label{display:block;font-weight:600;margin-bottom:.3rem;font-size:.9rem}
.form-group input,.form-group select,.form-group textarea{
  width:100%;border:1px solid var(--rule);border-radius:var(--radius);
  padding:.55rem .8rem;font-size:.95rem;font-family:var(--font-sans);background:var(--bg);color:var(--ink);
}
.form-group input:focus,.form-group select:focus,.form-group textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-soft)}
.form-group textarea{min-height:120px;resize:vertical;font-family:var(--font-mono)}
.form-row{display:grid;grid-template-columns:1fr 1fr;gap:1rem}

/* admin layout */
.admin-layout{display:grid;grid-template-columns:200px 1fr;gap:1.5rem;margin:1.5rem 0}
.admin-side{position:sticky;top:80px;align-self:start}
.admin-side h4{font-size:.78rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin-bottom:.5rem}
.admin-side ul{list-style:none}
.admin-side li{margin:.1rem 0}
.admin-side a{display:flex;align-items:center;gap:.5rem;padding:.45rem .7rem;border-radius:6px;font-size:.9rem;color:var(--ink)}
.admin-side a:hover{background:var(--primary-soft);color:var(--primary-dark)}
.admin-side a.active{background:var(--primary);color:#fff}
.admin-side a svg{width:17px;height:17px}
.admin-content{min-width:0}

/* stat cards */
.stat-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:1rem;margin:1.5rem 0}
.stat-card{background:var(--bg);border:1px solid var(--rule);border-radius:var(--radius);padding:1.1rem}
.stat-card .k{font-size:.78rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin-bottom:.3rem}
.stat-card .v{font-size:1.8rem;font-weight:700;font-family:var(--font-serif);color:var(--primary)}
.stat-card .sub{font-size:.78rem;color:var(--muted);margin-top:.2rem}

/* table */
.tbl-wrap{overflow-x:auto;border:1px solid var(--rule);border-radius:var(--radius);margin:1rem 0}
table.tbl{width:100%;border-collapse:collapse;font-size:.88rem;min-width:560px}
table.tbl th,table.tbl td{padding:.6rem .8rem;border-bottom:1px solid var(--rule);text-align:left;vertical-align:top}
table.tbl th{background:var(--bg2);font-weight:700;position:sticky;top:0}
table.tbl tr:hover{background:var(--bg2)}
table.tbl .mono{font-family:var(--font-mono);font-size:.82rem}
.badge{display:inline-block;font-size:.74rem;padding:.1rem .5rem;border-radius:999px;font-weight:600}
.badge.published{background:var(--primary-soft);color:var(--primary-dark)}
.badge.draft{background:var(--bg3);color:var(--muted)}

/* 404 */
.notfound{text-align:center;padding:4rem 1rem}
.notfound h1{font-size:5rem;color:var(--primary);margin-bottom:.5rem}
.notfound p{color:var(--muted);margin-bottom:1.5rem}

/* tool canvas areas */
.tool-panel{background:var(--bg);border:1px solid var(--rule);border-radius:var(--radius);padding:1.2rem;margin-bottom:1rem}
.tool-panel h3{margin-top:0}
.tool-controls{display:flex;flex-wrap:wrap;gap:.6rem;align-items:center;margin-bottom:1rem}
.tool-controls input[type=text]{border:1px solid var(--rule);border-radius:6px;padding:.5rem .8rem;font-family:var(--font-mono);font-size:.92rem;min-width:240px;background:var(--bg);color:var(--ink)}
.tool-controls input[type=text]:focus{outline:none;border-color:var(--primary)}
.tool-controls label{font-size:.88rem;color:var(--muted)}
.tool-result{font-family:var(--font-mono);font-size:1.1rem;background:var(--primary-soft);padding:.6rem 1rem;border-radius:6px;color:var(--primary-dark);min-height:2.2rem;word-break:break-all}

/* periodic table */
.ptable{display:grid;grid-template-columns:repeat(18,1fr);gap:2px;font-size:.62rem}
.ptable .el{
  background:var(--bg2);border:1px solid var(--rule);border-radius:3px;
  padding:2px;text-align:center;cursor:pointer;transition:transform .1s,background .15s;
  aspect-ratio:1/1;display:flex;flex-direction:column;justify-content:center;
}
.ptable .el:hover{transform:scale(1.15);z-index:5;position:relative;box-shadow:0 2px 8px rgba(0,0,0,.15)}
.ptable .el .num{font-size:.5rem;color:var(--muted);line-height:1}
.ptable .el .sym{font-weight:700;font-size:.8rem;line-height:1.1;font-family:var(--font-serif)}
.ptable .el .nm{font-size:.45rem;color:var(--muted);line-height:1}
.ptable .el.cat-alkali{background:#ffe0e0}
.ptable .el.cat-alkaline{background:#ffe9d0}
.ptable .el.cat-transition{background:#e0f0ff}
.ptable .el.cat-post{background:#e8f5e9}
.ptable .el.cat-metalloid{background:#fff9c4}
.ptable .el.cat-nonmetal{background:#f3e5f5}
.ptable .el.cat-halogen{background:#e0f7fa}
.ptable .el.cat-noble{background:#fce4ec}
.ptable .el.cat-lanth{background:#f0e0ff}
.ptable .el.cat-act{background:#ffe0f0}

/* chars dictionary */
.char-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(72px,1fr));gap:.5rem}
.char-cell{
  background:var(--bg);border:1px solid var(--rule);border-radius:6px;
  padding:.6rem;text-align:center;cursor:pointer;transition:border-color .15s;
}
.char-cell:hover{border-color:var(--primary);background:var(--primary-soft)}
.char-cell .ch{font-family:var(--font-serif);font-size:1.5rem;display:block;color:var(--ink)}
.char-cell .py{font-size:.7rem;color:var(--muted);display:block}
.letter-nav{display:flex;flex-wrap:wrap;gap:.3rem;margin:1rem 0}
.letter-nav a{padding:.2rem .5rem;border-radius:4px;font-family:var(--font-mono);font-size:.85rem;border:1px solid var(--rule)}
.letter-nav a:hover,.letter-nav a.active{background:var(--primary);color:#fff;border-color:var(--primary)}

/* responsive */
@media(max-width:860px){
  .grid.cols-3,.grid.cols-4{grid-template-columns:repeat(2,1fr)}
  .layout-2col{grid-template-columns:1fr}
  .filter-side{position:static}
  .admin-layout{grid-template-columns:1fr}
  .admin-side{position:static}
  .admin-side ul{display:flex;flex-wrap:wrap;gap:.3rem}
  .stat-grid{grid-template-columns:repeat(2,1fr)}
  .nav{display:none}
  .nav.open{display:flex;position:absolute;top:60px;left:0;right:0;flex-direction:column;background:var(--bg);border-bottom:1px solid var(--rule);padding:.5rem 1rem}
  .menu-toggle{display:block}
  .nav-search{display:none}
}
@media(max-width:560px){
  .grid.cols-2{grid-template-columns:1fr}
  .form-row{grid-template-columns:1fr}
  .post-card{flex-direction:column}
  .post-card .cover{width:100%;height:140px}
  .mat-item{flex-direction:column}
  .mat-actions{align-self:flex-start}
  .ptable{font-size:.5rem;grid-template-columns:repeat(9,1fr)}
}