* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 40px 20px;
    color: #333;
}
.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    padding: 40px;
    max-width: 600px;
    width: 100%;
}
h1 {
    font-size: 1.8rem;
    margin-bottom: 24px;
    color: #4a4a7a;
}
.settings {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}
.settings label { font-size: 1rem; color: #555; }
.settings input[type="number"] {
    width: 70px;
    font-size: 1.1rem;
    padding: 6px 10px;
    border: 2px solid #ddd;
    border-radius: 8px;
    text-align: center;
}
.top-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
}
.mode-tabs {
    display: flex;
    gap: 0;
}
.mode-tabs button {
    padding: 8px 24px;
    font-size: 0.95rem;
    border: 2px solid #ddd;
    background: #f8f9ff;
    color: #555;
    cursor: pointer;
    transition: all 0.2s;
}
.mode-tabs button:first-child { border-radius: 8px 0 0 8px; }
.mode-tabs button:last-child { border-radius: 0 8px 8px 0; }
.mode-tabs button.active {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    border-color: #667eea;
}
.display-area {
    min-height: 180px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f8f9ff;
    border-radius: 12px;
    margin-bottom: 20px;
    padding: 16px;
}
.number { font-family: 'Courier New', monospace; color: #333; line-height: 1.6; user-select: none; overflow-wrap: break-word; }
#comparison { font-family: 'Courier New', monospace; letter-spacing: 2px; line-height: 1.6; }
#userInput {
    width: 100%;
    font-size: 1.3rem;
    padding: 12px 16px;
    border: 2px solid #ddd;
    border-radius: 10px;
    text-align: center;
    font-family: 'Courier New', monospace;
    line-height: 1.6;
    outline: none;
    transition: border-color 0.2s;
    visibility: hidden;
    margin-bottom: 20px;
    resize: none;
    overflow: hidden;
    display: block;
}
#userInput:focus { border-color: #667eea; }
#actionButton {
    font-size: 1.3rem;
    padding: 12px 40px;
    border: none;
    border-radius: 10px;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    cursor: pointer;
    transition: transform 0.1s, box-shadow 0.2s;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}
#actionButton:hover { transform: translateY(-1px); box-shadow: 0 6px 20px rgba(102, 126, 234, 0.5); }
#actionButton:active { transform: translateY(0); }
#result {
    font-size: 1.2rem;
    margin-top: 16px;
    font-weight: 600;
}
.correct { color: #28a745; }
.wrong { color: #dc3545; font-weight: bold; }
#timer { font-size: 0.85rem; color: #aaa; margin-top: 8px; }
hr { border: none; border-top: 1px solid #eee; margin: 16px 0; }
#highscores { text-align: center; }
#highscores h3 { font-size: 1.2rem; color: #4a4a7a; margin-bottom: 12px; }
#highscores table { width: 100%; border-collapse: collapse; }
#highscores th, #highscores td { padding: 8px 12px; font-size: 0.9rem; border-bottom: 1px solid #eee; }
#highscores th { background: #f8f9ff; color: #555; font-weight: 600; }
#highscores tr:hover { background: #f8f9ff; }
.highlight-row { background: #d4edda !important; }
.hidden { display: none; }
.delete-score-btn {
    background: none;
    border: none;
    color: #bbb;
    font-size: 1rem;
    cursor: pointer;
    line-height: 1;
    padding: 2px 4px;
    border-radius: 4px;
    transition: color 0.15s, background 0.15s;
}
.delete-score-btn:hover { color: #dc3545; background: #fff0f0; }

@media (max-width: 480px) {
    body {
        padding: 16px 10px;
    }
    .container {
        padding: 24px 16px;
        border-radius: 14px;
    }
    h1 {
        font-size: 1.4rem;
        margin-bottom: 16px;
    }
    .top-bar {
        flex-direction: column;
        align-items: stretch;
        gap: 12px;
    }
    .mode-tabs {
        width: 100%;
    }
    .mode-tabs button {
        flex: 1;
        padding: 10px 0;
        font-size: 0.9rem;
    }
    .settings {
        justify-content: center;
    }
    .display-area {
        min-height: 140px;
        padding: 10px;
    }
    #userInput {
        font-size: 1.1rem;
        padding: 10px 12px;
    }
    #actionButton {
        width: 100%;
        font-size: 1.1rem;
        padding: 14px;
    }
    #result {
        font-size: 1rem;
    }
    #highscores th, #highscores td {
        padding: 6px 6px;
        font-size: 0.8rem;
    }
}