*, *::before, *::after {
            box-sizing: border-box;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: #f4f6f9;
            color: #333333;
            margin: 0;
            padding: 0;
            line-height: 1.5;
        }
        header {
            background-color: #1e293b;
            color: #ffffff;
            padding: 20px;
            text-align: center;
            border-bottom: 4px solid #3b82f6;
            box-shadow: 0 4px 6px rgba(0,0,0,0.1);
        }
        header h1 {
            margin: 0;
            font-size: 24px;
            font-weight: 600;
        }
        header p {
            margin: 5px 0 0 0;
            color: #94a3b8;
            font-size: 14px;
        }
        .container {
            max-width: 800px;
            margin: 30px auto;
            padding: 0 20px;
        }
        .card {
            background: #ffffff;
            border-radius: 8px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
            padding: 30px;
            margin-bottom: 24px;
            border: 1px solid #e2e8f0;
        }
        h2 {
            color: #1e293b;
            margin-top: 0;
            border-left: 4px solid #3b82f6;
            padding-left: 12px;
            font-size: 20px;
        }
        .btn {
            display: inline-block;
            background-color: #3b82f6;
            color: white;
            padding: 12px 24px;
            border: none;
            border-radius: 6px;
            cursor: pointer;
            font-size: 16px;
            font-weight: 500;
            transition: background-color 0.2s;
            text-align: center;
            width: 100%;
        }
        .btn:hover {
            background-color: #2563eb;
        }
        .btn-secondary {
            background-color: #64748b;
        }
        .btn-secondary:hover {
            background-color: #475569;
        }
        .input-group {
            margin-bottom: 20px;
        }
        .input-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
            color: #475569;
        }
        .input-group input, .input-group select {
            width: 100%;
            padding: 12px;
            border: 1px solid #cbd5e1;
            border-radius: 6px;
            font-size: 16px;
            background-color: #f8fafc;
        }
        .input-group input:focus {
            outline: none;
            border-color: #3b82f6;
            background-color: #fff;
        }
        #lock-screen {
            max-width: 450px;
            margin: 100px auto;
        }
        .lock-icon {
            font-size: 48px;
            text-align: center;
            margin-bottom: 15px;
        }
        .error-msg {
            color: #ef4444;
            margin-top: 10px;
            font-size: 14px;
            display: none;
            font-weight: 500;
        }
        .grid-menu {
            display: block;
        }
        .menu-item {
            background: #f8fafc;
            border: 1px solid #e2e8f0;
            border-radius: 6px;
            padding: 15px;
            margin-bottom: 12px;
            cursor: pointer;
            transition: all 0.2s;
        }
        .menu-item:hover {
            border-color: #3b82f6;
            background-color: #f0fdf4;
        }
        .menu-item h3 {
            margin: 0 0 5px 0;
            color: #1e293b;
        }
        .hidden {
            display: none !important;
        }
        .progress-bar {
            background-color: #e2e8f0;
            height: 8px;
            border-radius: 4px;
            margin-bottom: 25px;
            overflow: hidden;
        }
        .progress-fill {
            background-color: #10b981;
            height: 100%;
            width: 0%;
            transition: width 0.3s;
        }
        .question-text {
            font-size: 18px;
            font-weight: 600;
            margin-bottom: 20px;
            color: #0f172a;
        }
        .option-card {
            border: 1px solid #cbd5e1;
            border-radius: 6px;
            padding: 15px;
            margin-bottom: 12px;
            cursor: pointer;
            transition: all 0.2s;
            background-color: #ffffff;
        }
        .option-card:hover {
            background-color: #f1f5f9;
            border-color: #94a3b8;
        }
        .option-card.selected {
            border-color: #3b82f6;
            background-color: #eff6ff;
            font-weight: 500;
        }
        .option-card.correct {
            border-color: #10b981 !important;
            background-color: #ecfdf5 !important;
            color: #065f46;
        }
        .option-card.incorrect {
            border-color: #ef4444 !important;
            background-color: #fef2f2 !important;
            color: #991b1b;
        }
        .quiz-controls {
            margin-top: 25px;
        }
        .history-table {
            width: 100%;
            border-collapse: collapse;
            margin-top: 15px;
        }
        .history-table th, .history-table td {
            padding: 12px;
            text-align: left;
            border-bottom: 1px solid #e2e8f0;
        }
        .history-table th {
            background-color: #f1f5f9;
            color: #475569;
            font-weight: 600;
        }
        .badge {
            padding: 4px 8px;
            border-radius: 4px;
            font-size: 12px;
            font-weight: 600;
        }
        .badge-success { background-color: #d1fae5; color: #065f46; }
        .badge-danger { background-color: #fee2e2; color: #991b1b; }
        /* Styl pro znění norem v textu otázky */
        .norma {
            color: #2563eb;       /* Modrá barva textu normy */
            font-size: 0.85em;    /* Mírně menší písmo, aby norma nerušila hlavní otázku */
            font-weight: 500;     /* Středně tučné písmo */
            display: block;       /* Posune normu automaticky na nový řádek pod otázku */
            margin-top: 8px;      /* Mezera nad normou */
            color: #475569;       /* Pokud chceš raději elegantní břidlicově šedou, odmaž tento řádek */
        }
    

/* Serverová verze */
.small-note { color: #64748b; font-size: 13px; margin-top: 8px; }
.loading { opacity: 0.65; pointer-events: none; }
.option-card.disabled { cursor: default; opacity: 0.8; }

/* Registrace, přihlášení a admin */
.muted { color: #64748b; font-size: 14px; }
.tabs { display: flex; gap: 8px; margin: 22px 0; }
.tab { flex: 1; padding: 12px; border: 1px solid #cbd5e1; background: #f8fafc; border-radius: 8px; cursor: pointer; font-weight: 600; }
.tab.active { background: #2563eb; color: #fff; border-color: #2563eb; }
.success-msg { display: none; margin-top: 14px; padding: 12px; background: #ecfdf5; color: #065f46; border: 1px solid #a7f3d0; border-radius: 8px; }
.error-msg { display: none; margin-top: 14px; padding: 12px; background: #fef2f2; color: #991b1b; border: 1px solid #fecaca; border-radius: 8px; }
.info-box { margin: 18px 0; padding: 14px; background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 10px; line-height: 1.5; }
.info-box.warning { background: #fffbeb; border-color: #fde68a; color: #92400e; }
.banner-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 12px; margin-top: 24px; }
.banner { display: block; padding: 14px; border: 1px solid #cbd5e1; border-radius: 10px; text-decoration: none; color: #0f172a; background: #fff; transition: 0.2s; }
.banner:hover { transform: translateY(-2px); box-shadow: 0 8px 20px rgba(15, 23, 42, 0.08); border-color: #2563eb; }
.banner span { display: block; color: #64748b; font-size: 13px; margin-top: 4px; }
.account-bar { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-bottom: 18px; margin-bottom: 20px; border-bottom: 1px solid #e2e8f0; }
.small-btn { width: auto; padding: 10px 14px; margin-left: 6px; }
.admin-table { font-size: 14px; }
.admin-table .actions { min-width: 280px; }
.admin-table .actions button { margin: 3px; padding: 6px 8px; border: 1px solid #cbd5e1; border-radius: 6px; background: #fff; cursor: pointer; }
.admin-table .actions button:hover { background: #f1f5f9; }
@media (max-width: 700px) {
  .account-bar { display: block; }
  .account-bar > div:last-child { margin-top: 12px; }
  .admin-table { display: block; overflow-x: auto; }
}