*, *::before, *::after {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f7f6;
    color: #2c3e50;
    margin: 0;
    padding: 0;
    font-size: 15pt;
    line-height: 1.6;
}

.container {
    max-width: 850px;
    margin: 20px auto;
    background: #ffffff;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
}

h1, h2, h3 {
    color: #1e3c72;
    margin-top: 0;
}

h1 {
    text-align: center;
    border-bottom: 2px solid #ecf0f1;
    padding-bottom: 15px;
    margin-bottom: 25px;
}

.view-section {
    display: none;
    animation: fadeIn 0.2s ease-in-out;
}

.view-section.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(3px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Navigácia a Filtre */
.filter-wrapper {
    display: flex;
    gap: 15px;
    margin-bottom: 25px;
    background: #f8fafc;
    padding: 15px;
    border-radius: 8px;
    border: 1px solid #e2e8f0;
    flex-wrap: wrap;
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 5px;
    flex: 1;
    min-width: 120px;
}

.filter-group.select-lekcia {
    flex: 2;
    min-width: 200px;
}

.filter-group label {
    font-size: 11pt;
    font-weight: bold;
    color: #64748b;
    text-transform: uppercase;
}

.filter-group select {
    padding: 10px;
    font-size: 13pt;
    font-weight: bold;
    border: 2px solid #cbd5e1;
    border-radius: 6px;
    background-color: #ffffff;
    color: #1e293b;
    cursor: pointer;
}

/* Hlavné Výberové Menu */
.menu-grid {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-top: 20px;
}

.btn-menu {
    display: block;
    width: 100%;
    padding: 20px;
    font-size: 16pt;
    font-weight: bold;
    text-align: left;
    background: #ffffff;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    color: #334155;
}

.btn-menu:hover {
    background: #f0f7ff;
    border-color: #3b82f6;
    color: #1d4ed8;
    transform: translateX(4px);
}

/* Tlačidlá navigácie */
.btn-back {
    display: inline-block;
    background: #475569;
    color: white;
    padding: 12px 24px;
    font-size: 13pt;
    font-weight: bold;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    margin-bottom: 25px;
}

.btn-back:hover {
    background: #334155;
}

.footer-nav {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px dashed #cbd5e1;
}

.btn-lang {
    display: inline-block;
    padding: 12px 24px;
    background: #f1f5f9;
    color: #475569;
    text-decoration: none;
    font-weight: bold;
    font-size: 12pt;
    border-radius: 6px;
    border: 1px solid #cbd5e1;
}

.btn-lang:hover {
    background: #e2e8f0;
    color: #1e293b;
}

/* Režim: Čítanie textu */
.text-p {
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid #f1f5f9;
}

.orig-text {
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 6px;
}

.trans-text {
    color: #64748b;
    font-style: italic;
}

/* Režim: Slovníček */
.vocab-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 15px;
    font-size: 14pt;
}

.vocab-table th, .vocab-table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #e2e8f0;
}

.vocab-table th {
    background-color: #f8fafc;
    color: #475569;
    font-weight: bold;
}

.vocab-table tr:hover {
    background-color: #f8fafc;
}

.vocab-table td:first-child {
    font-weight: bold;
    color: #1e3c72;
    width: 45%;
}

.td-level {
    color: #94a3b8;
    font-weight: bold;
    font-size: 12pt;
}

/* Režim: Kvíz */
.quiz-container {
    text-align: center;
    padding: 10px;
}

.quiz-counter {
    font-size: 12pt;
    color: #94a3b8;
    font-weight: bold;
    margin-bottom: 15px;
    text-transform: uppercase;
}

.quiz-card {
    background: #f8fafc;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    padding: 40px 20px;
    margin-bottom: 25px;
    min-height: 180px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

#quiz-question {
    font-size: 18pt;
    font-weight: bold;
    color: #0f172a;
    margin: 0;
}

#quiz-answer {
    font-size: 18pt;
    font-weight: bold;
    color: #16a34a;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 2px dashed #cbd5e1;
    width: 80%;
}

.quiz-controls {
    display: flex;
    justify-content: center;
    gap: 15px;
    align-items: center;
}

.btn-quiz {
    padding: 12px 25px;
    font-size: 13pt;
    font-weight: bold;
    border: none;
    border-radius: 6px;
    cursor: pointer;
}

.btn-quiz-nav {
    background: #0ea5e9;
    color: white;
}

#reveal-btn {
    background: #10b981;
    color: white;
    padding: 15px 35px;
    font-size: 15pt;
}