@import url('https://fonts.googleapis.com/css2?family=Sora:wght@300;600;700&family=DM+Sans:wght@400;500&display=swap');

:root {
  --bg: #0f172a;
  --card: #1e293b;
  --hover: #263548;
  --accent: #6366f1;
  --accent2: #8b5cf6;
  --glow: rgba(99,102,241,0.3);
  --text: #f1f5f9;
  --muted: #94a3b8;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --border: rgba(255,255,255,0.08);
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
}

*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:'DM Sans',sans-serif;background:var(--bg);color:var(--text);min-height:100vh;line-height:1.6}
h1,h2,h3,h4{font-family:'Sora',sans-serif}
a{color:var(--accent);text-decoration:none}

/* Scrollbar */
::-webkit-scrollbar{width:6px;height:6px}
::-webkit-scrollbar-track{background:var(--card)}
::-webkit-scrollbar-thumb{background:var(--accent);border-radius:3px}

/* ========== LAYOUT ========== */
.container{max-width:1200px;margin:0 auto;padding:0 20px}

/* Admin sidebar layout */
.admin-wrap{display:flex;min-height:100vh}
.sidebar{width:240px;background:var(--card);border-right:1px solid var(--border);position:fixed;top:0;left:0;height:100vh;display:flex;flex-direction:column;z-index:100;transition:.3s}
.sidebar-logo{padding:28px 24px 20px;border-bottom:1px solid var(--border)}
.sidebar-logo h2{font-family:'Sora',sans-serif;font-size:1.1rem;color:var(--text);font-weight:700}
.sidebar-logo span{color:var(--accent)}
.sidebar-nav{flex:1;padding:16px 0;overflow-y:auto}
.nav-item{display:flex;align-items:center;gap:12px;padding:12px 24px;color:var(--muted);font-size:.92rem;font-weight:500;transition:.2s;cursor:pointer;border-left:3px solid transparent}
.nav-item:hover,.nav-item.active{color:var(--text);background:rgba(99,102,241,.08);border-left-color:var(--accent)}
.nav-item svg{width:18px;height:18px;flex-shrink:0}
.main-content{margin-left:240px;flex:1;padding:32px;min-height:100vh}

/* ========== TOPBAR ========== */
.topbar{display:flex;justify-content:space-between;align-items:center;margin-bottom:32px}
.topbar h1{font-size:1.6rem;font-weight:700}
.topbar-actions{display:flex;gap:10px}

/* ========== BUTTONS ========== */
.btn{display:inline-flex;align-items:center;gap:8px;padding:10px 20px;border-radius:8px;font-family:'DM Sans',sans-serif;font-size:.9rem;font-weight:500;cursor:pointer;border:none;transition:.2s;white-space:nowrap}
.btn:hover{transform:translateY(-1px)}
.btn-primary{background:var(--accent);color:#fff}
.btn-primary:hover{background:#5457e5;box-shadow:0 4px 12px var(--glow)}
.btn-danger{background:rgba(239,68,68,.15);color:var(--danger);border:1px solid rgba(239,68,68,.3)}
.btn-danger:hover{background:var(--danger);color:#fff}
.btn-ghost{background:transparent;color:var(--muted);border:1px solid var(--border)}
.btn-ghost:hover{color:var(--text);border-color:var(--accent)}
.btn-success{background:rgba(16,185,129,.15);color:var(--success);border:1px solid rgba(16,185,129,.3)}
.btn-success:hover{background:var(--success);color:#fff}
.btn-sm{padding:6px 14px;font-size:.82rem}

/* ========== CARDS ========== */
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:24px;transition:.2s}
.card:hover{border-color:rgba(99,102,241,.25)}

/* Stats grid */
.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:16px;margin-bottom:28px}
.stat-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:20px 24px;display:flex;align-items:center;gap:16px;transition:.2s}
.stat-card:hover{transform:translateY(-2px);box-shadow:var(--shadow);border-color:rgba(99,102,241,.25)}
.stat-icon{width:48px;height:48px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:1.4rem;flex-shrink:0}
.stat-icon.blue{background:rgba(99,102,241,.15)}
.stat-icon.green{background:rgba(16,185,129,.15)}
.stat-icon.yellow{background:rgba(245,158,11,.15)}
.stat-icon.purple{background:rgba(139,92,246,.15)}
.stat-label{font-size:.8rem;color:var(--muted);margin-bottom:4px}
.stat-value{font-size:1.7rem;font-weight:700;font-family:'Sora',sans-serif}

/* ========== TABLE ========== */
.table-wrap{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}
.table-header{padding:16px 20px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
table{width:100%;border-collapse:collapse}
thead th{padding:12px 16px;text-align:left;font-size:.78rem;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);background:rgba(255,255,255,.02);border-bottom:1px solid var(--border);font-weight:600;white-space:nowrap}
tbody tr{transition:.15s}
tbody tr:hover{background:var(--hover)}
tbody td{padding:12px 16px;border-bottom:1px solid var(--border);font-size:.9rem;vertical-align:middle}
tbody tr:last-child td{border-bottom:none}

/* Score cells */
td.score-cell{text-align:center;font-weight:600;border-radius:6px;cursor:pointer;min-width:64px}
td.score-gioi{background:rgba(16,185,129,.12);color:#34d399}
td.score-kha{background:rgba(99,102,241,.12);color:#818cf8}
td.score-tb{background:rgba(245,158,11,.12);color:#fbbf24}
td.score-yeu{background:rgba(239,68,68,.12);color:#f87171}
td.score-none{background:rgba(148,163,184,.06);color:var(--muted)}

/* Inline score input */
.score-input{width:64px;background:rgba(99,102,241,.1);border:2px solid var(--accent);border-radius:6px;color:var(--text);font-size:.9rem;font-weight:600;text-align:center;padding:4px 6px;outline:none}

/* Rank badge */
.rank-badge{display:inline-block;padding:3px 10px;border-radius:20px;font-size:.75rem;font-weight:600}
.rank-gioi{background:rgba(16,185,129,.15);color:#34d399}
.rank-kha{background:rgba(99,102,241,.15);color:#818cf8}
.rank-tb{background:rgba(245,158,11,.15);color:#fbbf24}
.rank-yeu{background:rgba(239,68,68,.15);color:#f87171}
.rank-none{background:rgba(148,163,184,.1);color:var(--muted)}

/* ========== SEARCH ========== */
.search-box{position:relative;flex:1;max-width:320px}
.search-box input{width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border);border-radius:8px;padding:9px 16px 9px 40px;color:var(--text);font-size:.9rem;outline:none;transition:.2s}
.search-box input:focus{border-color:var(--accent);box-shadow:0 0 0 3px var(--glow)}
.search-box svg{position:absolute;left:12px;top:50%;transform:translateY(-50%);color:var(--muted);width:16px;height:16px}
mark{background:rgba(99,102,241,.35);color:var(--text);border-radius:3px;padding:0 2px}

/* ========== MODAL ========== */
.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.6);backdrop-filter:blur(6px);z-index:1000;display:flex;align-items:center;justify-content:center;opacity:0;pointer-events:none;transition:.25s}
.modal-overlay.show{opacity:1;pointer-events:all}
.modal{background:var(--card);border:1px solid var(--border);border-radius:16px;padding:28px;width:100%;max-width:440px;transform:translateY(20px);transition:.25s;box-shadow:0 20px 60px rgba(0,0,0,.5)}
.modal-overlay.show .modal{transform:translateY(0)}
.modal-title{font-family:'Sora',sans-serif;font-size:1.1rem;font-weight:700;margin-bottom:20px;display:flex;align-items:center;gap:10px}
.modal-footer{display:flex;gap:10px;justify-content:flex-end;margin-top:20px}

/* Form elements */
.form-group{margin-bottom:16px}
.form-label{display:block;font-size:.82rem;color:var(--muted);margin-bottom:6px;font-weight:500}
.form-input{width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border);border-radius:8px;padding:10px 14px;color:var(--text);font-size:.9rem;outline:none;transition:.2s;font-family:'DM Sans',sans-serif}
.form-input:focus{border-color:var(--accent);box-shadow:0 0 0 3px var(--glow)}
select.form-input option{background:var(--card)}

/* ========== TOAST ========== */
.toast-container{position:fixed;bottom:24px;right:24px;z-index:9999;display:flex;flex-direction:column;gap:8px}
.toast{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:12px 18px;display:flex;align-items:center;gap:10px;font-size:.88rem;min-width:240px;max-width:360px;box-shadow:var(--shadow);animation:slideIn .3s ease;border-left:4px solid var(--accent)}
.toast.success{border-left-color:var(--success)}
.toast.error{border-left-color:var(--danger)}
.toast.warning{border-left-color:var(--warning)}
@keyframes slideIn{from{transform:translateX(100%);opacity:0}to{transform:translateX(0);opacity:1}}
@keyframes slideOut{to{transform:translateX(110%);opacity:0}}
.toast.removing{animation:slideOut .3s ease forwards}

/* ========== SKELETON ========== */
.skeleton{background:linear-gradient(90deg,var(--card) 25%,var(--hover) 50%,var(--card) 75%);background-size:200% 100%;animation:shimmer 1.5s infinite;border-radius:6px}
@keyframes shimmer{0%{background-position:200% 0}100%{background-position:-200% 0}}
.skeleton-row td{padding:14px 16px}
.skeleton-cell{height:14px;border-radius:4px}

/* ========== PUBLIC PAGES ========== */
.public-header{background:linear-gradient(135deg,#0f172a 0%,#1a1040 50%,#0f172a 100%);border-bottom:1px solid var(--border);padding:0;position:sticky;top:0;z-index:50;backdrop-filter:blur(20px)}
.public-nav{display:flex;align-items:center;justify-content:space-between;padding:16px 0;max-width:1200px;margin:0 auto;padding-left:20px;padding-right:20px}
.public-logo{font-family:'Sora',sans-serif;font-size:1.2rem;font-weight:700}
.public-logo span{color:var(--accent)}
.nav-links{display:flex;gap:8px}
.nav-link{padding:8px 18px;border-radius:8px;font-size:.9rem;color:var(--muted);transition:.2s}
.nav-link:hover,.nav-link.active{color:var(--text);background:rgba(99,102,241,.1)}

/* Hero section */
.hero{padding:64px 0 40px;text-align:center}
.hero h1{font-size:2.8rem;font-weight:700;margin-bottom:12px;background:linear-gradient(135deg,var(--text) 0%,var(--accent) 100%);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero p{color:var(--muted);font-size:1.1rem;max-width:480px;margin:0 auto 32px}

/* Search hero */
.search-hero{max-width:520px;margin:0 auto;position:relative}
.search-hero input{width:100%;padding:16px 24px 16px 52px;background:var(--card);border:1px solid var(--border);border-radius:14px;color:var(--text);font-size:1rem;outline:none;transition:.3s;font-family:'DM Sans',sans-serif}
.search-hero input:focus{border-color:var(--accent);box-shadow:0 0 0 4px var(--glow)}
.search-hero svg{position:absolute;left:18px;top:50%;transform:translateY(-50%);color:var(--muted);width:20px;height:20px}

/* Student card grid */
.students-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px;padding:32px 0}

/* Student card */
.student-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:0;overflow:hidden;transition:.25s;cursor:default}
.student-card:hover{transform:translateY(-3px);box-shadow:0 8px 32px rgba(0,0,0,.4);border-color:rgba(99,102,241,.3)}
.sc-header{padding:20px 20px 14px;border-bottom:1px solid var(--border);display:flex;align-items:center;gap:14px}
.sc-avatar{width:46px;height:46px;border-radius:12px;display:flex;align-items:center;justify-content:center;font-family:'Sora',sans-serif;font-size:1.1rem;font-weight:700;flex-shrink:0}
.sc-name{font-family:'Sora',sans-serif;font-weight:600;font-size:1rem;margin-bottom:2px}
.sc-class{font-size:.8rem;color:var(--muted)}
.sc-body{padding:16px 20px}
.sc-scores{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:12px}
.sc-score-item{display:flex;flex-direction:column;align-items:center;background:rgba(255,255,255,.03);border:1px solid var(--border);border-radius:8px;padding:8px 12px;min-width:70px}
.sc-score-label{font-size:.7rem;color:var(--muted);margin-bottom:4px;white-space:nowrap}
.sc-score-val{font-weight:700;font-size:1rem;font-family:'Sora',sans-serif}
.sc-footer{display:flex;align-items:center;justify-content:space-between;padding-top:10px;border-top:1px solid var(--border)}
.sc-avg{font-size:.85rem;color:var(--muted)}
.sc-avg strong{color:var(--text);font-weight:700;font-size:1rem;font-family:'Sora',sans-serif}

/* ========== RANKING PAGE ========== */
.top3-grid{display:grid;grid-template-columns:1fr 1.15fr 1fr;gap:16px;margin-bottom:36px;align-items:end}
.top3-card{background:var(--card);border:1px solid var(--border);border-radius:16px;padding:28px 20px;text-align:center;position:relative;transition:.3s;overflow:hidden}
.top3-card::before{content:'';position:absolute;top:0;left:0;right:0;height:3px}
.top3-card.gold::before{background:linear-gradient(90deg,#f59e0b,#fbbf24)}
.top3-card.silver::before{background:linear-gradient(90deg,#94a3b8,#cbd5e1)}
.top3-card.bronze::before{background:linear-gradient(90deg,#cd7c54,#e8a07a)}
.top3-card:hover{transform:translateY(-4px);box-shadow:0 12px 40px rgba(0,0,0,.5)}
.top3-medal{font-size:2.4rem;margin-bottom:8px;display:block}
.top3-rank{font-size:.75rem;color:var(--muted);font-weight:600;text-transform:uppercase;letter-spacing:.08em;margin-bottom:6px}
.top3-name{font-family:'Sora',sans-serif;font-weight:700;font-size:1.05rem;margin-bottom:2px}
.top3-class{font-size:.8rem;color:var(--muted);margin-bottom:12px}
.top3-avg{font-size:2rem;font-weight:700;font-family:'Sora',sans-serif;color:var(--accent)}

/* Progress arrow */
.progress-up{color:var(--success);font-weight:600}
.progress-down{color:var(--danger);font-weight:600}
.progress-eq{color:var(--muted)}

/* ========== LOGIN PAGE ========== */
.login-page{min-height:100vh;display:flex;align-items:center;justify-content:center;background:radial-gradient(ellipse at 30% 40%,rgba(99,102,241,.12) 0%,transparent 60%),radial-gradient(ellipse at 70% 60%,rgba(139,92,246,.08) 0%,transparent 60%),var(--bg)}
.login-card{width:100%;max-width:420px;background:var(--card);border:1px solid var(--border);border-radius:20px;padding:40px;box-shadow:0 20px 60px rgba(0,0,0,.5)}
.login-logo{text-align:center;margin-bottom:32px}
.login-logo h1{font-size:1.4rem;font-weight:700;margin-bottom:4px}
.login-logo p{color:var(--muted);font-size:.88rem}
.login-error{background:rgba(239,68,68,.1);border:1px solid rgba(239,68,68,.25);border-radius:8px;padding:10px 14px;font-size:.85rem;color:#f87171;margin-bottom:16px;display:none}
.login-error.show{display:block}

/* ========== CHARTS ========== */
.charts-grid{display:grid;grid-template-columns:2fr 1fr;gap:16px;margin-bottom:28px}
.chart-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:20px}
.chart-title{font-family:'Sora',sans-serif;font-size:.95rem;font-weight:600;margin-bottom:16px;color:var(--text)}

/* ========== IMPORT PAGE ========== */
.drop-zone{border:2px dashed var(--border);border-radius:var(--radius);padding:48px;text-align:center;transition:.2s;cursor:pointer}
.drop-zone:hover,.drop-zone.drag-over{border-color:var(--accent);background:rgba(99,102,241,.04)}
.drop-zone svg{width:48px;height:48px;color:var(--muted);margin-bottom:12px}
.drop-zone p{color:var(--muted);font-size:.9rem}
.drop-zone strong{color:var(--accent)}

/* ========== PAGINATION ========== */
.pagination{display:flex;align-items:center;gap:6px;justify-content:center;padding:20px}
.page-btn{width:36px;height:36px;border-radius:8px;border:1px solid var(--border);background:transparent;color:var(--muted);cursor:pointer;font-size:.88rem;transition:.2s;display:flex;align-items:center;justify-content:center}
.page-btn:hover{border-color:var(--accent);color:var(--text)}
.page-btn.active{background:var(--accent);border-color:var(--accent);color:#fff}

/* ========== RESPONSIVE ========== */
@media(max-width:1024px){
  .sidebar{width:64px}
  .sidebar-logo h2,.nav-item span{display:none}
  .nav-item{justify-content:center;padding:14px}
  .main-content{margin-left:64px;padding:20px}
  .charts-grid{grid-template-columns:1fr}
}
@media(max-width:640px){
  .sidebar{transform:translateX(-100%);width:240px}
  .sidebar.open{transform:translateX(0)}
  .main-content{margin-left:0;padding:16px}
  .hero h1{font-size:1.8rem}
  .top3-grid{grid-template-columns:1fr;align-items:start}
  .stats-grid{grid-template-columns:1fr 1fr}
  .table-wrap{overflow-x:auto}
  .topbar{flex-wrap:wrap;gap:12px}
}

/* ========== MISC ========== */
.empty-state{text-align:center;padding:60px 20px;color:var(--muted)}
.empty-state svg{width:56px;height:56px;margin-bottom:12px;opacity:.4}
.divider{height:1px;background:var(--border);margin:20px 0}
.badge{display:inline-block;padding:2px 10px;border-radius:20px;font-size:.75rem;font-weight:600}
.loading-spinner{width:18px;height:18px;border:2px solid rgba(255,255,255,.2);border-top-color:#fff;border-radius:50%;animation:spin .7s linear infinite;display:inline-block}
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes bounce{0%,100%{transform:translateY(0)}50%{transform:translateY(-8px)}}
.animate-bounce{animation:bounce 1s ease infinite}