/* ==========================================================================
   电力系统分析 · 课程教学辅助平台  共享样式表
   纯静态、零依赖、离线可用
   ========================================================================== */

:root{
  --navy:#0b2545;
  --navy-2:#123a6b;
  --blue:#1d4ed8;
  --cyan:#0ea5e9;
  --amber:#f59e0b;
  --green:#10b981;
  --red:#ef4444;
  --violet:#7c3aed;
  --ink:#0f2033;
  --ink-2:#33475e;
  --muted:#5b7089;
  --line:#e2e8f0;
  --bg:#eef3f9;
  --card:#ffffff;
  --radius:16px;
  --radius-sm:10px;
  --shadow:0 2px 4px rgba(15,32,51,.05),0 10px 28px -18px rgba(15,32,51,.35);
  --shadow-hover:0 6px 14px rgba(15,32,51,.10),0 22px 44px -22px rgba(15,32,51,.45);
  --font:"PingFang SC","Microsoft YaHei","Noto Sans SC","Hiragino Sans GB",system-ui,-apple-system,"Segoe UI",sans-serif;
  --mono:"Cascadia Mono","JetBrains Mono",Consolas,"SFMono-Regular",Menlo,monospace;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;font-family:var(--font);color:var(--ink);background:var(--bg);
  line-height:1.75;-webkit-font-smoothing:antialiased;
}
img{max-width:100%}
a{color:var(--blue);text-decoration:none}
a:hover{color:var(--cyan)}
h1,h2,h3,h4{line-height:1.35;margin:0 0 .5em}
p{margin:0 0 .9em}
ul,ol{margin:0 0 1em;padding-left:1.35em}
li{margin:.25em 0}
code,kbd{font-family:var(--mono);background:#eef2f8;border:1px solid var(--line);border-radius:6px;padding:.05em .35em;font-size:.9em;color:#1e3a8a}
hr{border:none;border-top:1px dashed var(--line);margin:1.6em 0}

.wrap{max-width:1180px;margin:0 auto;padding:0 20px}
.narrow{max-width:900px}

/* ============================ 顶部导航 ============================ */
header.top{
  position:sticky;top:0;z-index:60;
  background:linear-gradient(120deg,#08192f,#0b2545 40%,#123a6b);
  color:#dbeafe;box-shadow:0 2px 18px rgba(8,25,47,.35);
}
.top-inner{display:flex;align-items:center;gap:18px;height:64px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;color:#fff;font-size:1.02rem;white-space:nowrap}
.brand .bolt{
  display:grid;place-items:center;width:34px;height:34px;border-radius:10px;font-size:1.05rem;
  background:linear-gradient(135deg,var(--amber),#fb923c);color:#3b1d00;box-shadow:0 4px 12px rgba(245,158,11,.4)
}
.brand small{display:block;font-size:.63rem;font-weight:500;letter-spacing:.14em;color:#7ea6d8;text-transform:uppercase}
nav.mainnav{display:flex;gap:2px;margin-left:auto;flex-wrap:wrap}
nav.mainnav a{
  color:#bfd6f2;padding:8px 13px;border-radius:999px;font-size:.9rem;font-weight:600;transition:.25s
}
nav.mainnav a:hover{background:rgba(255,255,255,.1);color:#fff}
nav.mainnav a.active{background:linear-gradient(135deg,var(--cyan),var(--blue));color:#fff;box-shadow:0 6px 18px -8px var(--cyan)}
.nav-toggle{
  display:none;margin-left:auto;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.25);
  color:#fff;font-size:1.1rem;border-radius:10px;padding:6px 12px;cursor:pointer
}

/* ============================ 首屏 ============================ */
.hero{
  position:relative;overflow:hidden;color:#eaf3ff;
  background:
    radial-gradient(1100px 420px at 12% -10%,rgba(14,165,233,.38),transparent 60%),
    radial-gradient(900px 400px at 92% 8%,rgba(124,58,237,.32),transparent 62%),
    linear-gradient(140deg,#08192f,#0b2545 55%,#10305a);
}
.hero::after{
  content:"";position:absolute;inset:0;pointer-events:none;opacity:.5;
  background-image:linear-gradient(rgba(255,255,255,.05) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.05) 1px,transparent 1px);
  background-size:44px 44px;
  mask-image:linear-gradient(to bottom,rgba(0,0,0,.9),transparent 92%);
}
.hero .wrap{position:relative;z-index:2;padding-top:52px;padding-bottom:56px}
.hero h1{font-size:clamp(1.7rem,3.6vw,2.7rem);color:#fff;letter-spacing:.5px}
.hero.slim .wrap{padding-top:30px;padding-bottom:26px;text-align:center}
.hero.slim h1{margin-bottom:12px}
.hero.slim .role-banner.show{display:inline-block}
.hero .lead{font-size:clamp(.95rem,1.5vw,1.08rem);color:#b9d3f2;max-width:820px}
.hero .meta{display:flex;flex-wrap:wrap;gap:10px;margin:18px 0 24px}
.hero .meta span{
  background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.18);color:#cfe4ff;
  padding:5px 13px;border-radius:999px;font-size:.82rem;backdrop-filter:blur(4px)
}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px}
.hero .kpis{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:14px;margin-top:34px}
.hero .kpi{background:rgba(255,255,255,.07);border:1px solid rgba(255,255,255,.15);border-radius:14px;padding:14px 16px}
.hero .kpi b{display:block;font-size:1.5rem;color:#fff;font-family:var(--mono)}
.hero .kpi span{font-size:.78rem;color:#a9c6ea;letter-spacing:.04em}

/* 面包屑 */
.crumbs{background:#fff;border-bottom:1px solid var(--line);font-size:.84rem;color:var(--muted)}
.crumbs .wrap{padding:10px 20px}
.crumbs a{color:var(--muted)}
.crumbs a:hover{color:var(--blue)}
.crumbs span.sep{margin:0 7px;color:#c3d0e0}

/* ============================ 按钮 ============================ */
.btn{
  display:inline-flex;align-items:center;gap:8px;cursor:pointer;font-family:inherit;
  padding:10px 20px;border-radius:999px;border:1px solid rgba(255,255,255,.28);
  background:rgba(255,255,255,.09);color:#eaf3ff;font-size:.92rem;font-weight:600;
  transition:.25s;text-decoration:none
}
.btn:hover{transform:translateY(-2px);background:rgba(255,255,255,.18);color:#fff}
.btn.primary{background:linear-gradient(135deg,var(--cyan),var(--blue));border-color:transparent;color:#fff;box-shadow:0 10px 24px -12px var(--blue)}
.btn.amber{background:linear-gradient(135deg,var(--amber),#fb923c);border-color:transparent;color:#3b1d00;box-shadow:0 10px 24px -12px var(--amber)}
.btn.ghost{background:transparent;border-color:rgba(255,255,255,.35)}
.btn.sm{padding:7px 15px;font-size:.85rem}
/* 浅色背景下的按钮 */
body.light .btn,.sec .btn,.card .btn{background:#eef3fb;border-color:#d3e0f0;color:var(--navy)}
.card .btn:hover,.sec .btn:hover{background:#e2ebf8;color:var(--navy)}
.card .btn.primary,.sec .btn.primary{background:linear-gradient(135deg,var(--cyan),var(--blue));border-color:transparent;color:#fff}
.card .btn.amber,.sec .btn.amber{background:linear-gradient(135deg,var(--amber),#fb923c);border-color:transparent;color:#3b1d00}
.card .btn.ghost,.sec .btn.ghost{background:#fff}

/* ============================ 区块 ============================ */
.sec{padding:52px 0}
.sec-head{margin-bottom:26px}
.sec-head .eyebrow{font-size:.76rem;font-weight:800;letter-spacing:.22em;color:var(--cyan);text-transform:uppercase}
.sec-head h2{font-size:clamp(1.25rem,2.3vw,1.75rem);position:relative;padding-left:16px;margin-top:6px}
.sec-head h2::before{
  content:"";position:absolute;left:0;top:.18em;bottom:.18em;width:6px;border-radius:4px;
  background:linear-gradient(180deg,var(--cyan),var(--blue))
}
.sec-head .sub{color:var(--muted);font-size:.93rem;margin:0;padding-left:16px}

/* ============================ 卡片 / 栅格 ============================ */
.grid{display:grid;gap:18px}
.grid.g2{grid-template-columns:repeat(auto-fit,minmax(320px,1fr))}
.grid.g3{grid-template-columns:repeat(auto-fit,minmax(268px,1fr))}
.grid.g4{grid-template-columns:repeat(auto-fit,minmax(210px,1fr))}
.card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:22px 22px 20px;box-shadow:var(--shadow);transition:.28s
}
.card:hover{box-shadow:var(--shadow-hover);transform:translateY(-3px)}
.card h3{font-size:1.06rem;margin-bottom:.5em}
.card p:last-child{margin-bottom:0}
.card.flat:hover{transform:none;box-shadow:var(--shadow)}
.card .icon{
  width:44px;height:44px;border-radius:13px;display:grid;place-items:center;font-size:1.25rem;
  background:linear-gradient(135deg,#e0f2fe,#dbeafe);color:var(--blue);margin-bottom:12px
}
.card.tone-a .icon{background:linear-gradient(135deg,#dbeafe,#c7d2fe);color:#3730a3}
.card.tone-b .icon{background:linear-gradient(135deg,#cffafe,#bae6fd);color:#0369a1}
.card.tone-c .icon{background:linear-gradient(135deg,#fef3c7,#fde68a);color:#92400e}
.card.tone-d .icon{background:linear-gradient(135deg,#fee2e2,#fecaca);color:#b91c1c}
.card.tone-e .icon{background:linear-gradient(135deg,#dcfce7,#bbf7d0);color:#047857}

/* 功能入口大卡 */
.entry{position:relative;overflow:hidden;display:flex;flex-direction:column;min-height:230px}
.entry::before{
  content:"";position:absolute;right:-40px;top:-40px;width:150px;height:150px;border-radius:50%;
  background:radial-gradient(circle,rgba(14,165,233,.16),transparent 70%)
}
.entry .no{
  font-family:var(--mono);font-size:.78rem;font-weight:700;color:#94a8c0;letter-spacing:.15em
}
.entry h3{font-size:1.22rem;margin:.18em 0 .35em}
.entry .desc{color:var(--muted);font-size:.9rem;flex:1}
.entry .links{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}
.chip{
  font-size:.78rem;padding:3px 10px;border-radius:999px;background:#eef4fd;border:1px solid #dbe7f7;color:#25507f
}

/* ============================ 徽标 / 标签 ============================ */
.badge{display:inline-block;font-size:.74rem;font-weight:700;padding:2px 10px;border-radius:999px;letter-spacing:.02em}
.b-blue{background:#dbeafe;color:#1e40af}
.b-green{background:#dcfce7;color:#047857}
.b-amber{background:#fef3c7;color:#92400e}
.b-red{background:#fee2e2;color:#b91c1c}
.b-gray{background:#eef2f7;color:#475569}
.b-violet{background:#ede9fe;color:#5b21b6}
.tag{display:inline-block;font-size:.75rem;color:#4b6480;background:#f1f5f9;border:1px dashed #d7e0ea;border-radius:8px;padding:2px 9px;margin:0 6px 6px 0}

/* ============================ 公式 / 提示框 ============================ */
.formula{
  font-family:var(--mono);background:#f8fafc;border:1px solid var(--line);border-left:4px solid var(--cyan);
  border-radius:var(--radius-sm);padding:14px 16px;margin:14px 0;color:#0f2033;overflow-x:auto;
  font-size:.95rem;line-height:1.9
}
.formula .label{display:block;font-family:var(--font);font-size:.76rem;font-weight:700;color:var(--muted);letter-spacing:.08em;margin-bottom:4px}
.formula em{font-style:italic;font-family:"Times New Roman",serif;font-size:1.05em}
sub,sup{font-size:.72em}
.note{border-radius:var(--radius-sm);padding:13px 16px;margin:14px 0;font-size:.91rem;border:1px solid;background:#fff}
.note.tip{background:#f0f9ff;border-color:#bae6fd;color:#0c4a6e}
.note.key{background:#fffbeb;border-color:#fde68a;color:#78350f}
.note.warn{background:#fef2f2;border-color:#fecaca;color:#7f1d1d}
.note.ok{background:#f0fdf4;border-color:#bbf7d0;color:#14532d}
.note b{font-weight:800}

/* ============================ 表格 ============================ */
.tbl-wrap{overflow-x:auto;margin:14px 0;border-radius:var(--radius-sm);border:1px solid var(--line)}
table.tbl{width:100%;border-collapse:collapse;background:#fff;font-size:.88rem}
table.tbl th,table.tbl td{padding:9px 12px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
table.tbl th{background:#f3f7fc;font-weight:700;color:#24405f;white-space:nowrap}
table.tbl tbody tr:hover{background:#f8fbff}
table.tbl td.num,table.tbl th.num{text-align:right;font-family:var(--mono)}
.center{text-align:center}

/* ============================ 翻转卡片 ============================ */
.flip-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(258px,1fr));gap:16px;margin:18px 0}
.flip{perspective:1200px;height:212px;cursor:pointer;background:none;border:none;padding:0;font-family:inherit}
.flip-inner{position:relative;width:100%;height:100%;transition:transform .6s ease-in-out;transform-style:preserve-3d}
.flip.flipped .flip-inner{transform:rotateY(180deg)}
.flip-face{
  position:absolute;inset:0;backface-visibility:hidden;border-radius:var(--radius);padding:16px 17px;
  display:flex;flex-direction:column;overflow:auto;box-shadow:var(--shadow);text-align:left
}
.flip-front{background:linear-gradient(135deg,#123a6b,#1d4ed8 65%,#0ea5e9);color:#fff}
.flip-front h4{color:#fff;font-size:1.05rem;margin:auto 0 .35em}
.flip-front .cat{font-size:.72rem;letter-spacing:.1em;color:#bcd7f7;text-transform:uppercase}
.flip-front .hint{margin-top:auto;font-size:.74rem;color:#a9c9ee}
.flip-back{background:#fff;border:1px solid var(--line);transform:rotateY(180deg);color:var(--ink-2);font-size:.85rem}
.flip-back h5{margin:0 0 .35em;color:var(--navy);font-size:.9rem}
.flip .diff{font-size:.7rem;font-weight:700;padding:1px 8px;border-radius:999px;background:rgba(255,255,255,.2);color:#fff}
.diff.easy{background:rgba(16,185,129,.9)}
.diff.medium{background:rgba(245,158,11,.92);color:#3b1d00}
.diff.hard{background:rgba(239,68,68,.92)}
.flip .row{display:flex;align-items:center;gap:8px;justify-content:space-between}
.flip .master{
  margin-top:8px;background:#eef4fd;border:1px solid #d3e2f5;color:#1e4e8c;border-radius:999px;
  font-size:.75rem;padding:3px 10px;cursor:pointer;align-self:flex-start
}
.flip.mastered .flip-front{background:linear-gradient(135deg,#065f46,#10b981 70%,#34d399)}
.flip.mastered .master{background:#dcfce7;border-color:#86efac;color:#047857}

/* ============================ 自测题 ============================ */
.quiz{margin:18px 0}
.q{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:18px;margin-bottom:16px;box-shadow:var(--shadow)}
.q-stem{font-weight:700;color:var(--navy);margin-bottom:10px;display:flex;gap:8px;align-items:flex-start}
.q-stem .idx{
  flex:none;width:24px;height:24px;border-radius:8px;background:linear-gradient(135deg,var(--cyan),var(--blue));
  color:#fff;font-size:.78rem;display:grid;place-items:center;font-family:var(--mono);margin-top:3px
}
.opts{display:grid;gap:8px}
.opt{
  border:1px solid #dbe4ef;border-radius:12px;padding:9px 13px;cursor:pointer;background:#fbfdff;
  transition:.2s;font-size:.9rem;display:flex;gap:9px;align-items:flex-start
}
.opt:hover{background:#eef6ff;border-color:#a9cdf5}
.opt .k{font-weight:800;color:#3b6ea8;font-family:var(--mono)}
.opt.sel{border-color:var(--blue);background:#eaf2ff}
.opt.correct{border-color:var(--green);background:#effdf5}
.opt.correct .k{color:#047857}
.opt.wrong{border-color:var(--red);background:#fef4f4}
.opt.wrong .k{color:#b91c1c}
.opt.locked{cursor:default}
.feedback{margin-top:10px;font-size:.87rem;border-radius:10px;padding:10px 13px;display:none;line-height:1.7}
.feedback.show{display:block}
.feedback.ok{background:#f0fdf4;border:1px solid #bbf7d0;color:#14532d}
.feedback.no{background:#fef2f2;border:1px solid #fecaca;color:#7f1d1d}
.q-actions{margin-top:10px;display:flex;gap:8px;flex-wrap:wrap}
.quiz-result{
  background:linear-gradient(135deg,#0b2545,#123a6b);color:#fff;border-radius:var(--radius);
  padding:18px 22px;display:flex;flex-wrap:wrap;align-items:center;gap:16px;margin-top:6px
}
.quiz-result b{font-family:var(--mono);font-size:1.55rem;display:block}
.quiz-result .txt{font-size:.85rem;color:#b9d3f2}
.quiz-bar{height:8px;background:#dbe4ef;border-radius:999px;overflow:hidden;margin:14px 0}
.quiz-bar i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--cyan),var(--blue));transition:width .4s}

/* ============================ 手风琴 / 渐进式 ============================ */
.acc{margin:16px 0;border-radius:var(--radius);overflow:hidden;border:1px solid var(--line);background:#fff}
.acc-item+.acc-item{border-top:1px solid var(--line)}
.acc-head{
  display:flex;align-items:center;gap:12px;padding:15px 18px;cursor:pointer;font-weight:700;color:var(--navy);
  background:#fbfdff;transition:.22s;font-size:.97rem
}
.acc-head:hover{background:#f2f8ff}
.acc-head .n{
  flex:none;width:26px;height:26px;border-radius:8px;display:grid;place-items:center;font-family:var(--mono);font-size:.8rem;
  background:linear-gradient(135deg,#e0f2fe,#dbeafe);color:#1e40af
}
.acc-head .arrow{margin-left:auto;color:#8aa3bd;transition:transform .3s;font-size:.85rem}
.acc-item.open .acc-head{background:#eef6ff}
.acc-item.open .acc-head .arrow{transform:rotate(180deg)}
.acc-body{max-height:0;overflow:hidden;transition:max-height .45s ease;background:#fff}
.acc-item.open .acc-body{max-height:3200px}
.acc-body .inner{padding:6px 20px 20px 56px;color:var(--ink-2);font-size:.92rem}

/* ============================ 标签页 ============================ */
.tabs{margin:18px 0}
.tab-btns{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:14px}
.tab-btn{
  font-family:inherit;font-size:.88rem;font-weight:600;cursor:pointer;padding:8px 16px;border-radius:999px;
  border:1px solid #d3e0f0;background:#fff;color:#3a5573;transition:.22s
}
.tab-btn:hover{border-color:#a9cdf5;color:var(--blue)}
.tab-btn.active{background:linear-gradient(135deg,var(--cyan),var(--blue));color:#fff;border-color:transparent}
.tab-panel{display:none}
.tab-panel.active{display:block;animation:fadeUp .38s ease}
@keyframes fadeUp{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}

/* ============================ 计算工具 ============================ */
.tool{background:linear-gradient(135deg,#f7fbff,#eef5ff);border:1px solid #d7e6f7;border-radius:var(--radius);padding:18px;margin:18px 0}
.tool h4{margin:0 0 12px;color:var(--navy);font-size:1rem}
.tool-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:12px}
.tool-field{display:flex;flex-direction:column;gap:5px;font-size:.83rem;color:#3f5a78}
.tool-field input,.tool-field select{
  font-family:var(--mono);font-size:.9rem;padding:8px 10px;border:1px solid #cddff2;border-radius:9px;background:#fff;color:var(--ink)
}
.tool-field input:focus,.tool-field select:focus{outline:2px solid #bfe0ff;border-color:var(--cyan)}
.tool-out{
  margin-top:14px;background:#0b2545;color:#cfe6ff;border-radius:12px;padding:14px 16px;font-family:var(--mono);
  font-size:.87rem;line-height:1.9;white-space:pre-wrap;min-height:56px;overflow-x:auto
}
.tool-out b{color:#7dd3fc}
.tool-out .val{color:#fbbf24;font-weight:700}
.tool-out .ok{color:#4ade80}
.tool-out .bad{color:#f87171}

/* ============================ 进度条 ============================ */
.progress{height:10px;background:#e2e9f2;border-radius:999px;overflow:hidden;margin:10px 0 6px}
.progress i{display:block;height:100%;width:0;border-radius:999px;background:linear-gradient(90deg,var(--cyan),var(--blue));transition:width .45s}
.progress-txt{font-size:.8rem;color:var(--muted);font-family:var(--mono)}

/* ============================ 步骤条 ============================ */
ol.steps{counter-reset:s;list-style:none;padding:0;margin:16px 0}
ol.steps>li{
  counter-increment:s;position:relative;padding:0 0 16px 46px;border-left:2px dashed #d5e2f2;margin-left:14px
}
ol.steps>li:last-child{border-left-color:transparent;padding-bottom:0}
ol.steps>li::before{
  content:counter(s);position:absolute;left:-15px;top:-2px;width:28px;height:28px;border-radius:50%;
  background:linear-gradient(135deg,var(--cyan),var(--blue));color:#fff;display:grid;place-items:center;
  font-size:.8rem;font-weight:700;font-family:var(--mono);box-shadow:0 0 0 4px #fff
}
ol.steps>li b{color:var(--navy)}

/* ============================ 模块卡（知识学习） ============================ */
.mod-card{display:flex;gap:16px;align-items:flex-start}
.mod-card .mno{
  flex:none;width:52px;height:52px;border-radius:15px;display:grid;place-items:center;font-family:var(--mono);
  font-size:1.1rem;font-weight:800;color:#fff;background:linear-gradient(135deg,var(--cyan),var(--blue));
  box-shadow:0 8px 20px -10px var(--blue)
}
.mod-card .kps{margin-top:8px;display:flex;flex-wrap:wrap;gap:6px}

/* ============================ 榜单（作业打擂） ============================ */
.ladder{display:grid;gap:12px;margin:16px 0}
.ladder-row{
  display:flex;align-items:center;gap:14px;background:#fff;border:1px solid var(--line);border-radius:14px;
  padding:12px 16px;box-shadow:var(--shadow);transition:.25s
}
.ladder-row:hover{transform:translateX(3px)}
.ladder-row .rank{
  flex:none;width:34px;height:34px;border-radius:11px;display:grid;place-items:center;font-family:var(--mono);
  font-weight:800;background:#eef3f9;color:#4b6480
}
.ladder-row.r1 .rank{background:linear-gradient(135deg,#fbbf24,#f59e0b);color:#3b1d00}
.ladder-row.r2 .rank{background:linear-gradient(135deg,#e2e8f0,#cbd5e1);color:#334155}
.ladder-row.r3 .rank{background:linear-gradient(135deg,#fcd9b6,#f0b27a);color:#5b2b00}
.ladder-row .who{font-weight:700;color:var(--navy);min-width:96px}
.ladder-row .bar{flex:1;height:9px;background:#eef2f7;border-radius:999px;overflow:hidden}
.ladder-row .bar i{display:block;height:100%;background:linear-gradient(90deg,var(--cyan),var(--blue))}
.ladder-row .score{font-family:var(--mono);font-weight:800;color:var(--blue);min-width:74px;text-align:right}

/* ============================ 词云签到 ============================ */
.cloud-stage{
  position:relative;background:linear-gradient(135deg,#08192f,#0b2545 60%,#123a6b);border-radius:var(--radius);
  min-height:360px;overflow:hidden;box-shadow:var(--shadow)
}
.cloud-stage canvas{display:block;width:100%;height:360px}
.cloud-empty{
  position:absolute;inset:0;display:grid;place-items:center;color:#7ea6d8;font-size:.92rem;text-align:center;padding:20px
}
.stu-list{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}
.stu-pill{
  background:#fff;border:1px solid var(--line);border-radius:999px;padding:5px 13px;font-size:.82rem;
  display:inline-flex;align-items:center;gap:7px;box-shadow:0 1px 3px rgba(15,32,51,.06)
}
.stu-pill small{color:var(--muted);font-family:var(--mono)}

/* ============================ 仿真实验卡 ============================ */
.sim-card{display:flex;flex-direction:column;height:100%}
.sim-card .shot{
  height:132px;border-radius:12px;margin-bottom:14px;display:grid;place-items:center;color:#fff;
  font-family:var(--mono);font-size:.85rem;letter-spacing:.1em;text-align:center;padding:10px;
  background:linear-gradient(135deg,#0b2545,#1d4ed8 70%,#0ea5e9)
}
.sim-card .shot.g2{background:linear-gradient(135deg,#4c1d95,#7c3aed 70%,#c084fc)}
.sim-card .shot.g3{background:linear-gradient(135deg,#7c2d12,#ea580c 70%,#fbbf24)}
.sim-card .shot.g4{background:linear-gradient(135deg,#064e3b,#059669 70%,#34d399)}
.sim-card .shot.g5{background:linear-gradient(135deg,#1e293b,#0f766e 70%,#22d3ee)}

/* ============================ 页脚 ============================ */
footer.foot{
  background:linear-gradient(140deg,#08192f,#0b2545);color:#9fbcdd;margin-top:60px;padding:38px 0 26px;font-size:.87rem
}
footer.foot h4{color:#fff;font-size:.95rem;margin-bottom:10px}
footer.foot a{color:#9fbcdd}
footer.foot a:hover{color:#fff}
.foot-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:26px}
.foot-bottom{border-top:1px solid rgba(255,255,255,.12);margin-top:26px;padding-top:16px;display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between;font-size:.8rem;color:#7ea6d8}

/* ============================ 动效 ============================ */
.reveal{opacity:0;transform:translateY(18px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}
.float-in{animation:fadeUp .5s ease both}

/* ============================ 知识卡片（生动版） ============================ */
.flip-front .kp-ico{font-size:1.55rem;line-height:1;margin:10px 0 2px}
.flip-front h4{margin:6px 0 .3em;font-size:1.02rem}
.flip-front .kp-hook{font-size:.8rem;color:#cfe4ff;margin:0;line-height:1.65;opacity:.95}
.flip-back .kp-line{display:flex;gap:7px;align-items:flex-start;margin:0 0 .5em}
.flip-back .kp-line .lb{
  flex:none;font-size:.68rem;font-weight:800;letter-spacing:.04em;color:#fff;border-radius:6px;
  padding:1px 6px;margin-top:.28em
}
.kp-line.a .lb{background:#0ea5e9}
.kp-line.b .lb{background:#1d4ed8}
.kp-line.c .lb{background:#10b981}
.kp-line.d .lb{background:#f59e0b;color:#3b1d00}
.flip-back .kp-memo{
  margin:.6em 0 .35em;padding:6px 9px;border-radius:8px;background:#fffbeb;border:1px dashed #fcd34d;
  color:#78350f;font-size:.8rem;line-height:1.6
}
.flip-back .kp-viz{margin:.2em 0 .5em;font-size:.76rem;color:#0369a1}
.flip.kp-pop .flip-front{background:linear-gradient(135deg,#7c2d12,#ea580c 60%,#f59e0b)}

/* ============================ 知识点可视化实验室 ============================ */
.viz-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(438px,1fr));gap:18px;margin:18px 0}
.viz-card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px 18px 16px;
  box-shadow:var(--shadow);display:flex;flex-direction:column;transition:.28s
}
.viz-card:hover{box-shadow:var(--shadow-hover)}
.viz-kp{
  display:inline-block;font-family:var(--mono);font-size:.72rem;font-weight:700;color:#1d4ed8;
  background:#e7f1ff;border:1px solid #cfe3fb;border-radius:999px;padding:2px 10px;letter-spacing:.04em
}
.viz-card h3{font-size:1.02rem;margin:8px 0 4px}
.viz-card .viz-desc{font-size:.85rem;color:var(--muted);margin:0 0 12px;line-height:1.65}
.viz-stage{background:#f7fbff;border:1px solid #e3eef9;border-radius:12px;padding:8px;margin-bottom:12px}
.viz-stage svg{display:block;width:100%;height:auto}
.viz-stage canvas{display:block;width:100%;height:200px}
.viz-ctl{display:grid;grid-template-columns:repeat(auto-fit,minmax(146px,1fr));gap:10px 12px;margin-bottom:8px}
.viz-field{display:flex;flex-direction:column;gap:4px;font-size:.8rem;color:#3f5a78}
.viz-field input[type=range]{width:100%;accent-color:var(--blue);margin:0}
.viz-field input[type=number],.viz-field select{
  font-family:var(--mono);font-size:.86rem;padding:6px 8px;border:1px solid #cddff2;border-radius:8px;background:#fff;color:var(--ink)
}
.viz-field b{font-family:var(--mono);color:var(--blue);font-size:.82rem}
.viz-pick{display:flex;flex-wrap:wrap;gap:6px;margin:0 0 12px}
.viz-pick button{
  font-family:inherit;font-size:.78rem;cursor:pointer;padding:4px 11px;border-radius:999px;
  border:1px solid #d3e2f5;background:#fff;color:#31527a;transition:.2s
}
.viz-pick button:hover{border-color:#a9cdf5;background:#f0f7ff}
.viz-pick button.on{background:linear-gradient(135deg,var(--cyan),var(--blue));color:#fff;border-color:transparent}
.viz-card .tool-out{margin-top:12px;font-size:.85rem;min-height:44px}
.viz-card .tool-out .rowline{display:block;color:#cfe6ff}
.viz-card .tool-out .rowline b{color:#7dd3fc}
.viz-card .tool-out .val{color:#fbbf24;font-weight:700}
.viz-card .tool-out .good{color:#4ade80;font-weight:700}
.viz-card .tool-out .warn{color:#fbbf24;font-weight:700}
.viz-card .tool-out .bad{color:#f87171;font-weight:700}
.viz-matrix{width:100%;border-collapse:collapse;font-family:var(--mono);font-size:.8rem;margin:2px 0 10px}
.viz-matrix th,.viz-matrix td{border:1px solid #dbe4ef;padding:5px 8px;text-align:center;color:#cfe6ff}
.viz-matrix th{background:rgba(255,255,255,.07);color:#7dd3fc;font-weight:700}
.viz-matrix td.diag{background:rgba(14,165,233,.12);color:#7dd3fc}
.viz-matrix td.off{background:rgba(245,158,11,.12);color:#fcd34d}
.viz-flow{stroke-dasharray:7 9;animation:flowmove 1.4s linear infinite}
@keyframes flowmove{to{stroke-dashoffset:-32}}
.viz-card .tag{margin-bottom:0}

/* ============================ 响应式 ============================ */
@media (max-width:900px){
  nav.mainnav{
    position:absolute;top:64px;left:0;right:0;background:#0b2545;flex-direction:column;gap:0;
    padding:8px 12px 14px;display:none;box-shadow:0 18px 30px -18px rgba(0,0,0,.6)
  }
  nav.mainnav.open{display:flex}
  nav.mainnav a{border-radius:10px;padding:10px 12px}
  .nav-toggle{display:block}
  .hero .wrap{padding-top:34px;padding-bottom:38px}
  .sec{padding:36px 0}
  .acc-body .inner{padding-left:20px}
  .flip{height:236px}
  .viz-grid{grid-template-columns:1fr}
  .viz-card{padding:14px}
  .viz-stage canvas{height:180px}
}

/* ============================ 模块子页：分节导航 ============================ */
.subwrap{max-width:1180px;margin:0 auto;padding:26px 20px 64px;
  display:grid;grid-template-columns:236px 1fr;gap:30px;align-items:start}
.subnav{position:sticky;top:82px;background:#fff;border:1px solid var(--line);border-radius:14px;
  padding:14px 12px;box-shadow:0 8px 24px rgba(20,50,90,.07)}
.subnav-home{display:block;text-decoration:none;font-weight:700;color:var(--navy);
  background:#eef4fd;border-radius:9px;padding:9px 11px;margin-bottom:12px;font-size:.92rem}
.subnav-home:hover{background:#e2ebf8}
.subnav ol{list-style:none;margin:0;padding:0}
.subnav li{margin:2px 0}
.subnav li a{display:flex;gap:10px;align-items:center;text-decoration:none;
  color:#37507a;font-size:.9rem;line-height:1.35;padding:8px 9px;border-radius:9px}
.subnav li a .n{flex:none;width:22px;height:22px;border-radius:6px;background:#eaf0f8;color:#5b78a8;
  display:grid;place-items:center;font-size:.76rem;font-weight:800}
.subnav li a:hover:not(.active){background:#f3f7fc}
.subnav li a.active{background:var(--navy);color:#fff}
.subnav li a.active .n{background:rgba(255,255,255,.22);color:#fff}
.submain{min-width:0}
.submain .sec{padding-top:6px}
.subtitle{font-size:1.35rem;color:var(--navy);margin:4px 0 18px;padding-left:14px;position:relative}
.subtitle::before{content:"";position:absolute;left:0;top:4px;bottom:4px;width:5px;border-radius:3px;
  background:linear-gradient(180deg,var(--cyan),var(--blue))}
.subpager{display:flex;justify-content:space-between;align-items:center;gap:12px;
  margin:8px 0 24px;padding:10px 14px;border:1px solid var(--line);border-radius:11px;background:#fbfdff}
.subpager:last-child{margin-bottom:0}
.subpager a{text-decoration:none;color:var(--navy);font-weight:700;padding:7px 13px;border-radius:8px;
  border:1px solid var(--line);background:#fff}
.subpager a:hover{background:#eef4fd}
.subpager .pg-count{color:#6b82a8;font-size:.88rem;font-weight:600}

/* 模块首页：本节导航列表 */
.modsec-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px;margin-top:8px}
.modsec{display:flex;gap:14px;align-items:center;text-decoration:none;background:#fff;border:1px solid var(--line);
  border-radius:14px;padding:16px 18px;box-shadow:0 6px 18px rgba(20,50,90,.06);transition:transform .15s ease,box-shadow .15s ease,border-color .15s ease}
.modsec:hover{transform:translateY(-2px);box-shadow:0 12px 26px rgba(20,50,90,.12);border-color:#bcd2ec}
.modsec .ms-no{flex:none;width:42px;height:42px;border-radius:12px;display:grid;place-items:center;
  font-family:var(--mono);font-weight:800;font-size:1.05rem;color:#fff;
  background:linear-gradient(135deg,var(--cyan),var(--blue))}
.modsec:nth-child(2) .ms-no{background:linear-gradient(135deg,#7c3aed,#4f46e5)}
.modsec:nth-child(3) .ms-no{background:linear-gradient(135deg,#0ea5e9,#0369a1)}
.modsec:nth-child(4) .ms-no{background:linear-gradient(135deg,#ef4444,#b91c1c)}
.modsec:nth-child(5) .ms-no{background:linear-gradient(135deg,#f59e0b,#d97706)}
.modsec:nth-child(6) .ms-no{background:linear-gradient(135deg,#14b8a6,#0d9488)}
.modsec:nth-child(7) .ms-no{background:linear-gradient(135deg,#6366f1,#4338ca)}
.modsec:nth-child(8) .ms-no{background:linear-gradient(135deg,#10b981,#047857)}
.modsec:nth-child(9) .ms-no{background:linear-gradient(135deg,#ec4899,#be185d)}
.ms-body{display:flex;flex-direction:column;gap:3px;min-width:0}
.ms-name{font-weight:800;color:var(--navy);font-size:1.02rem}
.ms-go{font-size:.83rem;color:var(--blue);font-weight:600}
@media (max-width:880px){
  .subwrap{grid-template-columns:1fr}
  .subnav{position:static}
}

/* 模块首页：精简 hero（去掉按钮入口）与精简页脚（去掉四栏链接） */
.hero.slim-hero .wrap{padding-top:36px;padding-bottom:30px}
.hero.slim-hero .lead{margin-bottom:0}
footer.foot .foot-bottom:first-child{margin-top:0;padding-top:0;border-top:none}

@media print{
  header.top,footer.foot,.btn,.nav-toggle{display:none!important}
  body{background:#fff}
  .card{box-shadow:none;border-color:#ccc}
}

/* ============================ 登录账户区 ============================ */
.top-inner{flex-wrap:wrap}
.acct{margin-left:auto;display:flex;align-items:center;gap:10px;font-size:.86rem;color:var(--muted)}
.acct-user{display:inline-flex;align-items:center;gap:6px;color:var(--navy);font-weight:600}
.acct .role{font-style:normal;font-size:.7rem;padding:1px 8px;border-radius:999px;color:#fff}
.role-teacher{background:linear-gradient(135deg,#0b2545,#1d4ed8)}
.role-student{background:linear-gradient(135deg,#0e7490,#06b6d4)}
.acct-login{color:#fff;background:linear-gradient(135deg,var(--cyan),var(--blue));padding:6px 14px;border-radius:9px;font-weight:600}
.acct-logout{margin-left:4px;border:1px solid var(--line);background:#fff;color:var(--muted);padding:5px 12px;border-radius:9px;cursor:pointer;transition:.2s}
.acct-logout:hover{color:#b91c1c;border-color:#fca5a5}

/* 登录后首页欢迎横幅 */
.role-banner{display:none;margin:0 0 16px;padding:10px 16px;border-radius:12px;
  background:linear-gradient(135deg,#eef4fd,#e0f2fe);border:1px solid #cfe0f7;color:var(--navy);font-size:.92rem}
.role-banner.show{display:block}

/* ============================ 知识学习·模块导航 ============================ */
.modnav{display:grid;gap:14px;margin-top:8px}
.modnav-item{display:flex;align-items:center;gap:18px;padding:18px 22px;background:#fff;
  border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow);text-decoration:none;
  color:inherit;transition:.2s}
.modnav-item:hover{transform:translateX(6px);box-shadow:var(--shadow-hover);border-color:var(--blue)}
.mn-no{flex:none;width:54px;height:54px;border-radius:14px;display:grid;place-items:center;
  font-family:var(--mono);font-weight:800;font-size:1.25rem;color:#fff;
  background:linear-gradient(135deg,var(--cyan),var(--blue))}
.modnav-item:nth-child(2) .mn-no{background:linear-gradient(135deg,#7c3aed,#4f46e5)}
.modnav-item:nth-child(3) .mn-no{background:linear-gradient(135deg,#0ea5e9,#0369a1)}
.modnav-item:nth-child(4) .mn-no{background:linear-gradient(135deg,#ef4444,#b91c1c)}
.modnav-item:nth-child(5) .mn-no{background:linear-gradient(135deg,#10b981,#047857)}
.mn-body{flex:1;display:flex;flex-direction:column;gap:5px;min-width:0}
.mn-title{font-size:1.12rem;font-weight:800;color:var(--navy);display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.mn-tag{font-size:.72rem;font-weight:700;color:#1e4e8c;background:#eef4fd;border-radius:999px;padding:1px 9px}
.mn-desc{font-size:.9rem;color:var(--muted);line-height:1.5}
.mn-go{flex:none;font-weight:700;color:var(--blue);white-space:nowrap}