*{box-sizing:border-box;}
html,body{margin:0;padding:0;height:100%;font-family:'Segoe UI',system-ui,-apple-system,sans-serif;}
#bg-canvas{position:fixed;inset:0;z-index:-1;width:100%;height:100%;}
#app-root{position:relative;min-height:100vh;padding-top:64px;}
#topbar{position:fixed;top:0;left:0;right:0;height:64px;display:flex;align-items:center;
  justify-content:space-between;padding:0 20px;z-index:100;}
.brand{display:flex;align-items:center;gap:10px;}
.brand-name{font-weight:700;font-size:1.1rem;}
.brand-sub{font-size:.8rem;opacity:.7;}
.logo-dot{width:14px;height:14px;border-radius:50%;background:linear-gradient(135deg,#6ee7ff,#8b5cf6);box-shadow:0 0 10px #8b5cf6;}
.topbar-actions{display:flex;align-items:center;gap:10px;}

.screen{display:none;padding:24px;max-width:1400px;margin:0 auto;}
.screen.active{display:block;}

.home-hero{text-align:center;margin:20px auto 30px;max-width:700px;}
.home-hero h1{font-size:2rem;margin-bottom:8px;}
.home-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:18px;}
.home-card{display:flex;flex-direction:column;align-items:center;gap:8px;padding:24px 12px;cursor:pointer;border:none;}
.hc-icon{font-size:2rem;}

.build-layout{display:grid;grid-template-columns:260px 1fr 300px;gap:16px;height:calc(100vh - 110px);}
.palette-panel,.diagnostics-panel{overflow-y:auto;padding:16px;}
.palette-tabs{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:10px;}
.palette-list{display:flex;flex-direction:column;gap:8px;}
.workspace-panel{display:flex;flex-direction:column;gap:12px;}
.workspace-toolbar{display:flex;justify-content:space-between;align-items:center;padding:10px 16px;}
.toolbar-actions{display:flex;gap:8px;flex-wrap:wrap;}
.board-area{position:relative;flex:1;overflow:hidden;min-height:400px;}
#wire-layer{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;}
#slot-container{position:relative;display:grid;grid-template-columns:repeat(4,1fr);gap:14px;padding:24px;height:100%;align-content:start;}
.stat-strip{display:flex;gap:10px;overflow-x:auto;padding:8px;}

.learn-layout,.lab-layout{display:grid;grid-template-columns:280px 1fr;gap:16px;min-height:60vh;}
.learn-list,.lab-list{padding:12px;overflow-y:auto;max-height:75vh;}
.learn-content,.lab-content{padding:20px;}

.mission-grid,.achievement-grid,.progress-grid,.glossary-grid,.daily-grid{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px;margin:20px 0;}

.screen-title{margin-bottom:6px;}
.back-btn{margin-top:20px;}

.modal-overlay{position:fixed;inset:0;display:none;align-items:center;justify-content:center;z-index:1000;}
.modal-overlay.active{display:flex;}
.modal{max-width:520px;width:90%;padding:24px;max-height:80vh;overflow-y:auto;}

#toast-container{position:fixed;bottom:20px;right:20px;display:flex;flex-direction:column;gap:8px;z-index:1100;}

.ai-mentor{position:fixed;bottom:20px;left:20px;z-index:900;}
.ai-mentor-panel{position:absolute;bottom:60px;left:0;width:280px;max-height:340px;overflow-y:auto;
  padding:14px;display:none;}
.ai-mentor.open .ai-mentor-panel{display:block;}

@media (max-width: 1000px){
  .build-layout{grid-template-columns:1fr;height:auto;}
  .learn-layout,.lab-layout{grid-template-columns:1fr;}
}