:root {
    --primary-color: #6200ee;
    --accent-color: #03dac6;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-primary: #121212;
    --text-secondary: #5f6368;
}

body {
    font-family: 'Roboto', -apple-system, BlinkMacSystemFont, sans-serif;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-primary);
    -webkit-tap-highlight-color: transparent;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 0 16px;
}

.app-bar {
    background-color: var(--primary-color);
    color: white;
    padding: 16px 0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    position: sticky;
    top: 0;
    z-index: 100;
}

.app-bar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.app-bar h1 { margin: 0; font-size: 1.1rem; font-weight: 500; flex: 1; }

.region-selector {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 4px;
    padding: 4px 8px;
    font-size: 0.8rem;
    outline: none;
    cursor: pointer;
}

.region-selector option { color: #333; }

.tabs {
    display: flex;
    margin-top: 20px;
    background: #e8eaed;
    border-radius: 12px;
    padding: 4px;
}

.tabs button {
    flex: 1;
    border: none;
    padding: 12px;
    background: transparent;
    cursor: pointer;
    font-weight: 500;
    border-radius: 10px;
    transition: all 0.2s ease;
    color: var(--text-secondary);
}

.tabs button.active {
    background: white;
    color: var(--primary-color);
    box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

.loader {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
    font-style: italic;
}

.content-card {
    margin: 20px 0 100px 0;
    padding: 24px;
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.word-of-day {
    background: linear-gradient(135deg, var(--primary-color), #7b1fa2);
    color: white;
    padding: 20px;
    border-radius: 16px;
    margin-bottom: 20px;
}

.word-of-day h3 { margin: 0; font-size: 0.9rem; text-transform: uppercase; opacity: 0.8; }
.word-of-day .word { font-size: 2rem; font-weight: bold; margin: 10px 0; }
.word-of-day .phonetic { font-size: 0.9rem; margin-bottom: 8px; opacity: 0.9; }

.vocab-item {
    border-bottom: 1px solid #eee;
    padding: 12px 0;
}
.vocab-item:last-child { border-bottom: none; }
.vocab-word { font-weight: bold; color: var(--primary-color); font-size: 1.1rem; }
.vocab-meaning { color: var(--text-secondary); margin-top: 4px; }

.article-item {
    margin-bottom: 24px;
    cursor: pointer;
}
.article-item h2 { margin: 0 0 8px 0; font-size: 1.2rem; color: var(--text-primary); }
.article-item p { margin: 0; color: var(--text-secondary); font-size: 0.95rem; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }

.quiz-container {
    text-align: center;
}
.quiz-question { font-size: 1.2rem; margin-bottom: 20px; }
.quiz-question-block {
    text-align: left;
    margin-bottom: 30px;
    border-bottom: 1px dashed #ccc;
    padding-bottom: 20px;
}
.quiz-options { display: grid; gap: 10px; }
.quiz-option {
    background: white;
    padding: 12px;
    border: 2px solid #eee;
    border-radius: 8px;
    cursor: pointer;
    transition: 0.2s;
}
.quiz-option:hover { border-color: var(--primary-color); background: #f3e5f5; }

.error-msg { color: #d32f2f; text-align: center; padding: 20px; font-size: 0.9rem; }

.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: white;
    text-align: center;
    padding: 16px;
    border-top: 1px solid #eee;
    z-index: 99;
}
.bottom-nav a { color: var(--primary-color); text-decoration: none; font-weight: 500; }