body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.header {
    background: var(--header-bg);
    color: var(--header-text);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    text-align: center;
}

.controls {
    background: var(--card-bg);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--card-border);
}

.button {
    background: var(--button-bg);
    color: var(--button-text);
    border: none;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    margin-right: 10px;
    font-size: 14px;
    transition: background 0.3s;
}

.button:hover {
    background: var(--button-hover);
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

.card {
    background: var(--card-bg);
    border-radius: 10px;
    padding: 15px;
    box-shadow: var(--card-shadow);
    border-left: 4px solid var(--button-bg);
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.card h3 {
    margin: 0 0 10px 0;
    color: var(--text-color);
    font-size: 18px;
}

.card .english {
    color: var(--text-color);
    opacity: 0.8;
    font-size: 16px;
    margin-bottom: 10px;
}

.card .example,
.card .example-english {
    padding: 10px;
    border-radius: 6px;
    font-style: italic;
    font-size: 14px;
    margin-bottom: 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.card .example {
    background: var(--example-bg);
    color: var(--example-text);
    border-left: 4px solid #4682b4; /* Steel blue border */
}

.card .example-english {
    background: var(--example-english-bg);
    color: var(--example-english-text);
    border-left: 4px solid #3cb371; /* Main Navigation Styles */
}

.main-navigation {
    background: var(--card-bg);
    border-bottom: 2px solid var(--card-border);
    padding: 0;
    margin-bottom: 20px;
    box-shadow: var(--card-shadow);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.nav-brand h1 {
    margin: 0;
    color: var(--text-color);
    font-size: 1.5em;
}

.nav-items {
    display: flex;
    gap: 10px;
}

.nav-item {
    padding: 10px 20px;
    background: transparent;
    color: var(--text-color);
    border: 2px solid var(--card-border);
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    transition: all 0.3s ease;
}

.nav-item:hover {
    background: var(--button-hover-bg);
    color: var(--button-text);
}

.nav-item.active {
    background: var(--button-bg);
    color: var(--button-text);
    border-color: var(--button-bg);
}

/* Page Header Styles */
.page-header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
}

.page-header h2 {
    margin: 0 0 10px 0;
    color: var(--text-color);
    font-size: 2em;
}

.page-header p {
    margin: 0;
    color: var(--text-color);
    opacity: 0.8;
    font-size: 1.1em;
}

/* View-specific visibility */
.flashcard-view, .conjugation-view {
    display: none;
}

.flashcard-view.active, .conjugation-view.active {
    display: block;
}

/* Page headers and controls visibility */
#flashcards-header, #flashcards-controls {
    display: none;
}

.flashcard-view.active ~ #flashcards-header,
.flashcard-view.active ~ #flashcards-controls {
    display: block;
}

/* Mobile Navigation */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        gap: 15px;
        padding: 15px;
    }
    
    .nav-brand h1 {
        font-size: 1.3em;
    }
    
    .nav-items {
        width: 100%;
        justify-content: center;
    }
    
    .nav-item {
        flex: 1;
        text-align: center;
        padding: 12px 15px;
        font-size: 14px;
    }
    
    .page-header h2 {
        font-size: 1.6em;
    }
    
    .page-header p {
        font-size: 1em;
    }
}

.language-toggle-container {
    margin: 1rem 0;
    text-align: center;
}

.toggle-group {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
}

.mode-label {
    font-weight: 500;
    color: var(--text-color);
}

/* Toggle Switch */
.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #2196F3;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
}

input:checked + .slider {
    background-color: #4CAF50;
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}

.card .meta {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
}

.card .part-of-speech {
    background: var(--part-of-speech-bg);
    padding: 3px 8px;
    border-radius: 15px;
    font-size: 12px;
    color: var(--part-of-speech-text);
}

.card .difficulty {
    background: #28a745;
    color: white;
    padding: 3px 8px;
    border-radius: 15px;
    font-size: 12px;
    transition: background-color 0.3s ease;
}

.card .difficulty.intermediate {
    background: #ffc107;
    color: #212529;
}

.card .difficulty.advanced {
    background: #dc3545;
}

.card .tags {
    font-size: 11px;
    color: var(--text-color);
    opacity: 0.7;
}

.stats {
    background: var(--stats-bg);
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 20px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--stats-border);
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.stats h3, .stats h4 {
    margin: 0 0 10px 0;
    color: var(--stats-title);
}

.stats-section {
    margin-bottom: 20px;
}

.stats h4 {
    font-size: 16px;
    margin-bottom: 10px;
    padding-bottom: 5px;
    border-bottom: 1px solid var(--card-border);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.stat-item {
    text-align: center;
    padding: 10px;
    background: var(--card-bg);
    border-radius: 5px;
    border: 1px solid var(--card-border);
}

.stat-number {
    font-size: 24px;
    font-weight: bold;
    color: var(--stat-number, var(--button-bg));
    transition: color 0.3s ease;
}

.stat-label {
    font-size: 12px;
    color: var(--stat-label, var(--text-color));
    transition: color 0.3s ease;
}

.filter-controls {
    margin: 15px 0;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.filter-status {
    margin: 10px 0 20px;
    font-size: 14px;
    color: var(--filter-status-text);
    background-color: var(--filter-status-bg);
    padding: 8px 15px;
    border-radius: 20px;
    display: inline-block;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.filter-button {
    background: var(--filter-inactive);
    border: 1px solid var(--card-border);
    padding: 5px 10px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 12px;
    color: var(--filter-text);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.filter-button.active {
    background: var(--filter-active);
    color: var(--filter-active-text);
    border-color: var(--filter-active);
}

#downloadBtn {
    background: #28a745;
    transition: background-color 0.3s ease;
}

#downloadBtn:hover {
    background: #218838;
}