:root{
  --blue:#3168ff;--blue2:#6d5cff;--ink:#172033;--muted:#718096;--bg:#f5f8ff;--line:#e8eefb;--card:#ffffff;--green:#16a34a;--yellow:#f6c343;--red:#ef4444;
  --shadow:0 20px 60px rgba(49,104,255,.14);--radius:26px;
}
*{box-sizing:border-box} body{font-family:Inter,system-ui,-apple-system,Segoe UI,sans-serif;margin:0;background:linear-gradient(135deg,#f3f7ff 0%,#ffffff 42%,#eef4ff 100%);color:var(--ink)}
a{text-decoration:none}.text-muted{color:var(--muted)!important}.page-shell{min-height:100vh}.iahub-topbar{height:74px;background:rgba(255,255,255,.82);backdrop-filter:blur(18px);border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 7%;position:sticky;top:0;z-index:50}.brand{display:flex;align-items:center;gap:10px;font-weight:900;font-size:1.15rem;color:var(--ink)}.brand-mark{display:grid;place-items:center;width:40px;height:40px;border-radius:14px;background:linear-gradient(135deg,var(--blue),var(--blue2));color:white;box-shadow:var(--shadow)}.nav-actions{display:flex;align-items:center;gap:12px}.nav-chip{border:1px solid var(--line);color:var(--ink);background:white;border-radius:999px;padding:10px 14px;font-weight:700;font-size:.88rem}.nav-chip.primary{background:linear-gradient(135deg,var(--blue),var(--blue2));color:white;border:0}.teacher-pill{display:flex;align-items:center;gap:9px;border:1px solid var(--line);padding:7px 10px;border-radius:999px;background:#fff;font-weight:800}.teacher-pill small{font-size:.68rem;color:var(--muted);font-weight:800}.avatar{width:32px;height:32px;border-radius:50%;display:grid;place-items:center;background:#edf3ff;color:var(--blue);font-weight:900}.logout{width:40px;height:40px;border-radius:14px;background:#fff3f3;color:var(--red);display:grid;place-items:center}.hero{padding:80px 7% 60px;display:grid;grid-template-columns:1fr .9fr;gap:50px;align-items:center}.eyebrow{display:inline-flex;align-items:center;gap:8px;background:#fff;border:1px solid var(--line);padding:10px 14px;border-radius:999px;font-size:.82rem;font-weight:900;letter-spacing:.02em;color:var(--ink);box-shadow:0 8px 25px rgba(0,0,0,.04)}.hero h1{font-size:clamp(2.4rem,5vw,4.6rem);line-height:1.02;letter-spacing:-.06em;margin:22px 0 16px;font-weight:900}.gradient-text{background:linear-gradient(135deg,var(--blue),var(--blue2));-webkit-background-clip:text;background-clip:text;color:transparent}.hero p{max-width:620px;color:var(--muted);font-size:1.05rem;line-height:1.8}.hero-actions{display:flex;gap:14px;flex-wrap:wrap;margin-top:26px}.btn-main{background:linear-gradient(135deg,var(--blue),var(--blue2));color:white;border:0;border-radius:16px;padding:14px 20px;font-weight:900;box-shadow:var(--shadow)}.btn-soft{background:#fff;color:var(--ink);border:1px solid var(--line);border-radius:16px;padding:14px 20px;font-weight:900}.trust-row{display:flex;gap:20px;flex-wrap:wrap;margin-top:22px;color:#6b7b93;font-size:.9rem}.trust-row span{display:flex;align-items:center;gap:8px}.trust-row i{color:var(--green)}.preview-card{background:linear-gradient(135deg,#2d65ff,#573df3);border-radius:32px;padding:30px;color:white;box-shadow:0 25px 80px rgba(49,104,255,.28);position:relative;overflow:hidden}.preview-card:before{content:"";position:absolute;inset:-80px -60px auto auto;width:210px;height:210px;background:rgba(255,255,255,.12);border-radius:50%}.preview-head{display:flex;justify-content:space-between;font-size:.8rem;opacity:.88;margin-bottom:25px}.resource-mini{background:white;color:var(--ink);border-radius:18px;padding:18px;margin-bottom:14px;box-shadow:0 14px 30px rgba(10,25,80,.12)}.resource-mini.small{display:inline-block;width:48%;vertical-align:top;margin-right:2%}.resource-mini b{display:block}.tag{display:inline-flex;align-items:center;gap:6px;padding:6px 10px;border-radius:999px;background:#edf3ff;color:var(--blue);font-size:.72rem;font-weight:900}.tag.yellow{background:#fff6d9;color:#b77900}.tag.green{background:#e9f9ef;color:#15803d}.mini-meta{display:flex;justify-content:space-between;color:#7b8798;font-size:.78rem;margin-top:12px}.auth-wrap{min-height:100vh;display:grid;grid-template-columns:1fr 1fr}.auth-art{padding:70px;background:linear-gradient(135deg,#eaf1ff,#fff);display:flex;flex-direction:column;justify-content:center}.auth-box{display:flex;align-items:center;justify-content:center;padding:40px}.auth-card{width:min(520px,100%);background:white;border:1px solid var(--line);border-radius:28px;padding:34px;box-shadow:var(--shadow)}.form-control,.form-select{border-radius:15px;border:1px solid var(--line);padding:13px 15px}.form-label{font-weight:800;font-size:.86rem}.app-container{padding:34px 7% 70px}.dashboard-head{display:flex;justify-content:space-between;gap:20px;align-items:flex-end;margin-bottom:26px}.dashboard-head h1{font-weight:900;letter-spacing:-.04em}.quick-stats{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-bottom:24px}.stat-card{background:white;border:1px solid var(--line);border-radius:22px;padding:20px;box-shadow:0 10px 30px rgba(30,80,180,.06)}.stat-card i{width:42px;height:42px;border-radius:15px;display:grid;place-items:center;background:#eef4ff;color:var(--blue);margin-bottom:12px}.stat-card b{font-size:1.5rem}.filter-card,.content-card{background:white;border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:0 12px 34px rgba(30,80,180,.07)}.resource-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.resource-card{background:white;border:1px solid var(--line);border-radius:24px;padding:20px;box-shadow:0 12px 34px rgba(30,80,180,.07);transition:.25s}.resource-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}.resource-icon{width:54px;height:54px;border-radius:18px;display:grid;place-items:center;background:linear-gradient(135deg,#eef4ff,#fff);color:var(--blue);font-size:1.35rem}.resource-top{display:flex;justify-content:space-between;gap:15px;margin-bottom:14px}.resource-title{font-weight:900;font-size:1.04rem;margin:0 0 8px}.resource-desc{color:var(--muted);font-size:.9rem;line-height:1.55;min-height:42px}.resource-meta{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0}.pill{display:inline-flex;gap:6px;align-items:center;border-radius:999px;padding:7px 10px;background:#f3f6fb;color:#667085;font-size:.76rem;font-weight:800}.pill.private{background:#fff3e8;color:#b45309}.pill.public{background:#eafbf1;color:#168447}.card-actions{display:flex;gap:10px;margin-top:14px}.card-actions a,.card-actions button{flex:1;text-align:center;border:0;border-radius:14px;padding:11px 12px;font-weight:900}.view-btn{background:var(--blue);color:white}.download-btn{background:#f4f7ff;color:var(--blue)}.upload-zone{border:2px dashed #bfd0ff;border-radius:24px;padding:28px;background:#f8fbff;text-align:center}.upload-zone i{font-size:2.4rem;color:var(--blue);margin-bottom:12px}.reader{background:white;border:1px solid var(--line);border-radius:28px;padding:24px;box-shadow:var(--shadow)}.video-frame,iframe{width:100%;border:0;border-radius:20px;background:#111;min-height:420px}.doc-frame{width:100%;min-height:650px;border:1px solid var(--line);border-radius:20px}.comment{border:1px solid var(--line);border-radius:18px;padding:14px;background:#fbfcff;margin-bottom:10px}.alert{border-radius:16px}.empty-state{text-align:center;padding:55px 20px;color:var(--muted)}.empty-state i{font-size:3rem;color:#bfd0ff;margin-bottom:12px}@media(max-width:992px){.hero{grid-template-columns:1fr;padding-top:45px}.auth-wrap{grid-template-columns:1fr}.auth-art{display:none}.quick-stats{grid-template-columns:repeat(2,1fr)}.resource-grid{grid-template-columns:repeat(2,1fr)}.iahub-topbar{padding:0 4%}.nav-chip{display:none}}@media(max-width:650px){.resource-grid,.quick-stats{grid-template-columns:1fr}.dashboard-head{display:block}.app-container{padding:22px 4% 60px}.hero{padding:35px 4%}.preview-card{padding:20px}.resource-mini.small{width:100%;display:block}.teacher-pill small{display:none}.hero-actions a{width:100%;text-align:center}}