:root {
      --blue-900:#0b2545; --blue-700:#134074; --blue-500:#1a6fad; --blue-400:#2d9cdb;
      --blue-100:#ddeeff; --sky:#eaf4ff; --green:#28a86e; --green-light:#d6f4e8;
      --gold:#f4b942; --red:#e53935; --text:#0f1f2e; --muted:#5a7389;
      --card-bg:#ffffff; --bg:#f5f9ff;
      --radius-sm:10px; --radius-md:18px; --radius-lg:26px;
      --shadow-soft:0 2px 18px rgba(19,64,116,0.07);
      --shadow-hover:0 10px 40px rgba(19,64,116,0.15);
      --font-display:'DM Serif Display',Georgia,serif;
      --font-body:'DM Sans',system-ui,sans-serif;
    }
    *,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
    html{scroll-behavior:smooth;}
    body{font-family:var(--font-body);background:var(--bg);color:var(--text);min-height:100vh;opacity:0;transition:opacity .4s;}
    body.loaded{opacity:1;}
 
    /* AUTH GATE */
    #auth-gate{display:none;position:fixed;inset:0;z-index:3000;background:linear-gradient(135deg,var(--blue-900),var(--blue-700));align-items:center;justify-content:center;}
    #auth-gate.show{display:flex;}
    .gate-box{background:#fff;border-radius:var(--radius-lg);padding:3rem 2.5rem;max-width:420px;width:90%;text-align:center;box-shadow:0 30px 80px rgba(0,0,0,.35);animation:popIn .4s cubic-bezier(.175,.885,.32,1.275);}
    @keyframes popIn{from{transform:scale(.85);opacity:0;}to{transform:scale(1);opacity:1;}}
    .gate-icon{width:72px;height:72px;background:var(--sky);border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:2rem;color:var(--blue-500);margin:0 auto 1.5rem;}
    .gate-title{font-family:var(--font-display);font-size:1.9rem;color:var(--blue-900);margin-bottom:.5rem;}
    .gate-sub{font-size:.92rem;color:var(--muted);margin-bottom:2rem;line-height:1.7;}
    .gate-btn{display:inline-flex;align-items:center;gap:.5rem;background:var(--blue-700);color:#fff;padding:.9rem 2rem;border-radius:var(--radius-sm);font-weight:600;font-size:1rem;text-decoration:none;transition:background .2s,transform .2s;}
    .gate-btn:hover{background:var(--blue-900);transform:translateY(-2px);}
 
    /* NAVBAR */
    .navbar{position:sticky;top:0;z-index:200;background:rgba(255,255,255,.92);backdrop-filter:blur(18px);-webkit-backdrop-filter:blur(18px);border-bottom:1px solid rgba(19,64,116,.08);}
    .nav-inner{max-width:1280px;margin:0 auto;padding:0 1.5rem;display:flex;align-items:center;justify-content:space-between;height:68px;}
    .nav-brand{display:flex;align-items:center;gap:.6rem;text-decoration:none;}
    .nav-brand img{width:40px;height:40px;border-radius:50%;object-fit:cover;border:2px solid var(--blue-100);}
    .nav-brand span{font-family:var(--font-display);font-size:1.1rem;color:var(--blue-900);}
    .nav-links{display:flex;align-items:center;gap:.2rem;}
    .nav-link{display:inline-flex;align-items:center;gap:.4rem;padding:.45rem .9rem;border-radius:var(--radius-sm);color:var(--muted);text-decoration:none;font-size:.88rem;font-weight:500;transition:background .2s,color .2s;}
    .nav-link:hover,.nav-link.active{background:var(--sky);color:var(--blue-700);}
    .nav-link.active{font-weight:600;}
    .nav-btn{display:inline-flex;align-items:center;gap:.4rem;background:var(--blue-700);color:#fff;padding:.5rem 1.1rem;border-radius:var(--radius-sm);font-size:.88rem;font-weight:600;text-decoration:none;border:none;cursor:pointer;font-family:var(--font-body);transition:background .2s;}
    .nav-btn:hover{background:var(--blue-900);}
    .nav-toggle{display:none;background:none;border:none;font-size:1.3rem;color:var(--blue-900);cursor:pointer;}
 
    /* HERO */
    .hero{background:linear-gradient(135deg,var(--blue-900) 0%,var(--blue-700) 60%,#1e5fa0 100%);color:#fff;padding:52px 1.5rem 100px;text-align:center;position:relative;overflow:hidden;}
    .hero::before{content:'';position:absolute;inset:0;background:radial-gradient(circle at 20% 80%,rgba(45,156,219,.22) 0%,transparent 55%),radial-gradient(circle at 80% 15%,rgba(244,185,66,.12) 0%,transparent 50%);pointer-events:none;}
    .hero-badge{display:inline-flex;align-items:center;gap:.4rem;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.22);border-radius:50px;padding:.3rem .95rem;font-size:.75rem;font-weight:600;letter-spacing:.06em;text-transform:uppercase;margin-bottom:1.2rem;position:relative;}
    .hero-badge i{color:var(--gold);}
    .hero-title{font-family:var(--font-display);font-size:clamp(2rem,4.5vw,3.2rem);line-height:1.15;letter-spacing:-.02em;margin-bottom:.75rem;position:relative;}
    .hero-title em{font-style:italic;color:var(--gold);}
    .hero-sub{max-width:520px;margin:0 auto;font-size:.95rem;line-height:1.75;color:rgba(255,255,255,.75);font-weight:300;position:relative;}
 
    /* UPLOAD CARD — floats over hero bottom */
    .upload-float{max-width:1280px;margin:-62px auto 0;padding:0 1.5rem;position:relative;z-index:10;}
    .upload-card{background:var(--card-bg);border-radius:var(--radius-lg);box-shadow:0 8px 48px rgba(11,37,69,.16);border:1px solid rgba(19,64,116,.06);overflow:hidden;}
    .upload-card-head{background:linear-gradient(90deg,var(--blue-700) 0%,var(--blue-500) 100%);padding:1.05rem 1.8rem;display:flex;align-items:center;justify-content:space-between;cursor:pointer;user-select:none;gap:1rem;}
    .upload-head-left{display:flex;align-items:center;gap:.8rem;}
    .upload-head-ic{width:40px;height:40px;background:rgba(255,255,255,.15);border-radius:var(--radius-sm);display:flex;align-items:center;justify-content:center;font-size:1.15rem;color:#fff;flex-shrink:0;}
    .upload-head-title{font-family:var(--font-display);font-size:1.05rem;color:#fff;}
    .upload-head-sub{font-size:.78rem;color:rgba(255,255,255,.7);margin-top:.1rem;}
    .upload-chevron{color:rgba(255,255,255,.85);font-size:.9rem;transition:transform .3s;}
    .upload-chevron.open{transform:rotate(180deg);}
    .upload-body{display:none;padding:1.6rem 1.8rem;}
    .upload-body.open{display:block;}
    .upload-grid{display:grid;grid-template-columns:1fr 1fr 160px 160px;gap:.75rem;margin-bottom:.75rem;}
    .upload-full{grid-column:1/-1;}
    .up-lbl{display:block;font-size:.72rem;font-weight:600;color:var(--blue-700);text-transform:uppercase;letter-spacing:.05em;margin-bottom:.3rem;}
    .up-inp,.up-sel{width:100%;padding:.65rem .9rem;border:1.5px solid rgba(19,64,116,.14);border-radius:var(--radius-sm);font-family:var(--font-body);font-size:.9rem;color:var(--text);background:var(--bg);outline:none;transition:border-color .2s,box-shadow .2s;}
    .up-inp:focus,.up-sel:focus{border-color:var(--blue-400);box-shadow:0 0 0 3px rgba(45,156,219,.1);}
    .up-inp::placeholder{color:var(--muted);}
    .upload-foot{display:flex;align-items:center;gap:1rem;flex-wrap:wrap;}
    .up-submit{display:inline-flex;align-items:center;gap:.5rem;background:var(--blue-700);color:#fff;padding:.72rem 1.6rem;border-radius:var(--radius-sm);font-weight:700;font-size:.9rem;font-family:var(--font-body);border:none;cursor:pointer;transition:background .2s,transform .15s;}
    .up-submit:hover{background:var(--blue-900);transform:translateY(-1px);}
    .up-submit:disabled{opacity:.6;cursor:not-allowed;transform:none;}
    .up-hint{font-size:.78rem;color:var(--muted);}
    .up-hint i{color:var(--gold);margin-right:.25rem;}
    .up-ok{display:none;background:var(--green-light);color:var(--green);border-radius:var(--radius-sm);padding:.65rem 1rem;font-size:.86rem;font-weight:500;margin-top:.85rem;}
 
    /* FILTER BAR */
    .filter-bar{background:var(--card-bg);border-bottom:1px solid rgba(19,64,116,.07);position:sticky;top:68px;z-index:100;}
    .filter-inner{max-width:1280px;margin:0 auto;padding:.85rem 1.5rem;display:flex;align-items:center;gap:.85rem;flex-wrap:wrap;}
    .search-wrap{position:relative;flex:1;min-width:180px;max-width:300px;}
    .search-wrap i{position:absolute;left:.85rem;top:50%;transform:translateY(-50%);color:var(--muted);font-size:.85rem;pointer-events:none;}
    .search-inp{width:100%;padding:.6rem .9rem .6rem 2.4rem;border:1.5px solid rgba(19,64,116,.13);border-radius:var(--radius-sm);font-family:var(--font-body);font-size:.88rem;color:var(--text);background:var(--bg);outline:none;transition:border-color .2s;}
    .search-inp:focus{border-color:var(--blue-400);}
    .vdiv{width:1px;height:26px;background:rgba(19,64,116,.1);flex-shrink:0;}
    .filter-group{display:flex;align-items:center;gap:.4rem;flex-wrap:wrap;}
    .filter-lbl{font-size:.7rem;font-weight:700;color:var(--muted);text-transform:uppercase;letter-spacing:.07em;white-space:nowrap;}
    .fb{padding:.38rem .8rem;border:1.5px solid rgba(19,64,116,.13);border-radius:50px;background:transparent;color:var(--muted);font-family:var(--font-body);font-size:.78rem;font-weight:500;cursor:pointer;transition:all .18s;white-space:nowrap;}
    .fb:hover,.fb.active{background:var(--blue-700);border-color:var(--blue-700);color:#fff;}
    .filter-right{margin-left:auto;display:flex;align-items:center;gap:.6rem;}
    .sort-sel{padding:.4rem .75rem;border:1.5px solid rgba(19,64,116,.13);border-radius:var(--radius-sm);font-family:var(--font-body);font-size:.78rem;color:var(--muted);background:var(--bg);outline:none;cursor:pointer;}
    .res-count{font-size:.78rem;color:var(--muted);font-weight:500;white-space:nowrap;}
 
    /* MAIN */
    .main{max-width:1280px;margin:0 auto;padding:1.8rem 1.5rem 4rem;}
 
    /* STATS */
    .stats-row{display:grid;grid-template-columns:repeat(5,1fr);gap:.85rem;margin-bottom:2rem;}
    .stat-card{background:var(--card-bg);border-radius:var(--radius-md);padding:1.1rem 1.2rem;box-shadow:var(--shadow-soft);border:1px solid rgba(19,64,116,.05);display:flex;align-items:center;gap:.75rem;}
    .stat-ic{width:40px;height:40px;border-radius:var(--radius-sm);display:flex;align-items:center;justify-content:center;font-size:.95rem;flex-shrink:0;}
    .ic-b{background:var(--sky);color:var(--blue-500);}
    .ic-g{background:#fff8e8;color:var(--gold);}
    .ic-n{background:var(--green-light);color:var(--green);}
    .ic-p{background:var(--blue-100);color:var(--blue-700);}
    .ic-r{background:#fdecea;color:var(--red);}
    .stat-num{font-family:var(--font-display);font-size:1.5rem;color:var(--blue-900);line-height:1;}
    .stat-lbl{font-size:.7rem;color:var(--muted);text-transform:uppercase;letter-spacing:.04em;font-weight:500;margin-top:.12rem;}
 
    /* SAVED PANEL */
    .saved-panel{background:var(--card-bg);border-radius:var(--radius-md);box-shadow:var(--shadow-soft);border:1px solid rgba(19,64,116,.06);margin-bottom:1.5rem;overflow:hidden;}
    .saved-head{padding:1rem 1.4rem;display:flex;align-items:center;gap:.6rem;cursor:pointer;user-select:none;border-bottom:1px solid rgba(19,64,116,.06);}
    .saved-head-title{font-family:var(--font-display);font-size:1rem;color:var(--blue-900);flex:1;}
    .saved-count{font-size:.72rem;background:var(--gold);color:var(--blue-900);padding:.15rem .55rem;border-radius:50px;font-weight:700;}
    .saved-arrow{font-size:.8rem;color:var(--muted);transition:transform .25s;}
    .saved-arrow.open{transform:rotate(180deg);}
    .saved-body{display:none;padding:1rem 1.4rem;}
    .saved-body.open{display:block;}
    .saved-chips{display:flex;flex-wrap:wrap;gap:.55rem;}
    .saved-chip{display:inline-flex;align-items:center;gap:.45rem;background:var(--sky);color:var(--blue-700);padding:.35rem .85rem;border-radius:50px;font-size:.82rem;font-weight:500;text-decoration:none;border:none;cursor:pointer;font-family:var(--font-body);transition:background .2s;}
    .saved-chip:hover{background:var(--blue-100);}
    .chip-x{background:none;border:none;color:var(--muted);cursor:pointer;font-size:.72rem;padding:0;margin-left:.1rem;transition:color .2s;}
    .chip-x:hover{color:var(--red);}
    .saved-empty{font-size:.88rem;color:var(--muted);}
 
    /* YEAR ACCORDION */
    .year-block{background:var(--card-bg);border-radius:var(--radius-md);box-shadow:var(--shadow-soft);border:1px solid rgba(19,64,116,.06);margin-bottom:1rem;overflow:hidden;}
    .year-head{padding:1.1rem 1.5rem;display:flex;align-items:center;justify-content:space-between;cursor:pointer;user-select:none;transition:background .2s;}
    .year-head:hover{background:var(--sky);}
    .year-head.open{background:var(--blue-900);}
    .year-head-left{display:flex;align-items:center;gap:.8rem;}
    .year-emoji{font-size:1.2rem;}
    .year-title-text{font-family:var(--font-display);font-size:1.1rem;}
    .year-head:not(.open) .year-title-text{color:var(--blue-900);}
    .year-head.open .year-title-text{color:#fff;}
    .year-head-right{display:flex;align-items:center;gap:.7rem;}
    .year-badge{font-size:.72rem;font-weight:600;padding:.2rem .65rem;border-radius:50px;}
    .year-head:not(.open) .year-badge{background:var(--sky);color:var(--blue-700);}
    .year-head.open .year-badge{background:rgba(255,255,255,.18);color:#fff;}
    .year-arrow{font-size:.85rem;transition:transform .3s;}
    .year-head:not(.open) .year-arrow{color:var(--muted);}
    .year-head.open .year-arrow{color:#fff;transform:rotate(180deg);}
    .year-body{display:none;padding:1.2rem 1.5rem 1.5rem;background:#fafcff;}
    .year-body.open{display:block;}
 
    /* SUBJECT ROW — clickable tab */
    .subjects-tabs{display:flex;flex-wrap:wrap;gap:.5rem;margin-bottom:1.2rem;}
    .sub-tab{padding:.45rem 1rem;border:1.5px solid rgba(19,64,116,.13);border-radius:50px;background:transparent;color:var(--muted);font-family:var(--font-body);font-size:.82rem;font-weight:500;cursor:pointer;transition:all .18s;display:flex;align-items:center;gap:.4rem;}
    .sub-tab:hover,.sub-tab.active{background:var(--blue-700);border-color:var(--blue-700);color:#fff;}
    .sub-tab .sub-badge{font-size:.68rem;background:rgba(255,255,255,.2);padding:.1rem .4rem;border-radius:50px;}
    .sub-tab:not(.active) .sub-badge{background:var(--sky);color:var(--blue-500);}
 
    /* NOTES GRID */
    .notes-pane{display:none;}
    .notes-pane.active{display:block;}
    .notes-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(270px,1fr));gap:1rem;margin-top:.5rem;}
 
    /* NOTE CARD */
    .note-card{background:var(--card-bg);border-radius:var(--radius-md);border:1px solid rgba(19,64,116,.07);box-shadow:var(--shadow-soft);overflow:hidden;display:flex;flex-direction:column;transition:box-shadow .25s,transform .25s;}
    .note-card:hover{box-shadow:var(--shadow-hover);transform:translateY(-3px);}
    .note-top{padding:1.15rem 1.15rem .85rem;flex:1;}
    .type-badge{display:inline-flex;align-items:center;gap:.28rem;padding:.2rem .6rem;border-radius:50px;font-size:.7rem;font-weight:700;margin-bottom:.55rem;}
    .tb-notes{background:var(--sky);color:var(--blue-500);}
    .tb-paper{background:#fff8e8;color:#b07d00;}
    .tb-lab{background:var(--green-light);color:var(--green);}
    .tb-assign{background:#fce4ec;color:#c62828;}
    .tb-project{background:#f3e5f5;color:#6a1b9a;}
    .tb-other{background:#f0f0f0;color:var(--muted);}
    .note-title{font-weight:600;font-size:.93rem;color:var(--blue-900);line-height:1.4;margin-bottom:.25rem;}
    .note-uploader{font-size:.75rem;color:var(--muted);display:flex;align-items:center;gap:.3rem;margin-top:.3rem;}
    .note-bot{padding:.7rem 1.15rem;background:var(--bg);border-top:1px solid rgba(19,64,116,.05);display:flex;align-items:center;justify-content:space-between;gap:.5rem;}
    .note-actions{display:flex;align-items:center;gap:.3rem;}
    .icon-btn{background:none;border:none;cursor:pointer;padding:.3rem .35rem;border-radius:var(--radius-sm);font-size:.92rem;color:var(--muted);transition:color .2s,background .2s;display:flex;align-items:center;gap:.25rem;font-family:var(--font-body);font-size:.8rem;}
    .icon-btn:hover{background:var(--sky);color:var(--blue-700);}
    .icon-btn.liked{color:var(--red);}
    .icon-btn.saved-active{color:var(--gold);}
    .like-count{font-size:.75rem;font-weight:600;}
    .view-btn{display:inline-flex;align-items:center;gap:.35rem;background:var(--blue-700);color:#fff;padding:.42rem .9rem;border-radius:var(--radius-sm);font-size:.78rem;font-weight:600;text-decoration:none;transition:background .18s,transform .15s;white-space:nowrap;}
    .view-btn:hover{background:var(--blue-900);transform:translateY(-1px);}
 
    /* EMPTY / LOADING */
    .empty-state{text-align:center;padding:3rem 2rem;color:var(--muted);}
    .empty-state i{font-size:2.5rem;display:block;margin-bottom:.8rem;opacity:.35;}
    .loading-wrap{text-align:center;padding:3rem;color:var(--muted);}
    .spin{display:inline-block;animation:spin 1s linear infinite;font-size:1.8rem;color:var(--blue-400);}
    @keyframes spin{to{transform:rotate(360deg);}}
 
    /* TOAST */
    #toast{position:fixed;bottom:1.5rem;left:50%;transform:translateX(-50%) translateY(80px);background:var(--blue-900);color:#fff;padding:.65rem 1.4rem;border-radius:var(--radius-sm);font-size:.87rem;font-weight:500;z-index:4000;transition:transform .3s,opacity .3s;opacity:0;pointer-events:none;box-shadow:0 4px 20px rgba(0,0,0,.2);}
    #toast.show{transform:translateX(-50%) translateY(0);opacity:1;}
    #toast.ok{background:var(--green);}
    #toast.err{background:#c0392b;}
 
    /* FOOTER */
    footer{background:#081830;color:rgba(255,255,255,.5);padding:2rem 1.5rem;text-align:center;font-size:.85rem;}
    footer .fl{display:flex;justify-content:center;gap:1.5rem;flex-wrap:wrap;margin-bottom:.9rem;}
    footer a{color:rgba(255,255,255,.4);text-decoration:none;transition:color .2s;}
    footer a:hover{color:var(--gold);}
 
    /* RESPONSIVE */
    @media(max-width:1024px){.stats-row{grid-template-columns:repeat(3,1fr);}.upload-grid{grid-template-columns:1fr 1fr;}}
    @media(max-width:768px){
      .nav-links{display:none;flex-direction:column;position:absolute;top:68px;left:0;right:0;background:rgba(255,255,255,.97);padding:1rem 1.2rem;border-bottom:1px solid rgba(19,64,116,.08);gap:.2rem;}
      .nav-links.open{display:flex;}
      .nav-toggle{display:block;}
      .stats-row{grid-template-columns:repeat(2,1fr);}
      .upload-grid{grid-template-columns:1fr 1fr;}
      .vdiv{display:none;}
      .filter-right{display:none;}
      .hero{padding:48px 1.2rem 96px;}
    }
    @media(max-width:480px){
      .stats-row{grid-template-columns:1fr 1fr;}
      .upload-grid{grid-template-columns:1fr;}
      .notes-grid{grid-template-columns:1fr;}
      .main{padding:1.2rem 1rem 3rem;}
      .upload-float{padding:0 1rem;}
    }