:root {
    --primary-color: #1a6fc9;
    --secondary-color: #0d8b8b;
    --accent-color: #4db8ff;
    --light-color: #e6f7ff;
    --dark-color: #003366;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f5f9fc;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

.question-card {
    background: white;
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    margin-bottom: 20px;
}

.question-text {
    font-size: 1.1em;
    margin-bottom: 15px;
    color: var(--dark-color);
}

.answer-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    margin: 15px 0;
}

.input-group {
    display: flex;
    flex-direction: column;
    margin-right: 50px;
}

.input-label {
    font-size: 0.9em;
    margin-bottom: 5px;
    color: var(--secondary-color);
}

.answer-input {
    width: 100%;
    padding: 8px 12px;
    border: 2px solid var(--light-color);
    border-radius: 8px;
    font-size: 16px;
    min-height: 40px;
}

.symbol-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin-top: 10px;
}

.symbol-btn {
    background: var(--light-color);
    border: none;
    padding: 5px 10px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 16px;
    transition: background 0.3s;
}

.symbol-btn:hover {
    background: var(--accent-color);
}

.check-button {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 25px;
    border-radius: 20px;
    cursor: pointer;
    transition: background 0.3s;
}

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

.result-message {
    margin-top: 15px;
    padding: 10px;
    border-radius: 8px;
    display: none;
}

.correct {
    background: #e6ffe6;
    border: 2px solid #4CAF50;
}

.incorrect {
    background: #ffebee;
    border: 2px solid #f44336;
}

.warning {
    background: #fff;
    border: 2px solid #f4ee36;
    margin-bottom: 15px;
    font-weight: bold;
    padding: 10px;
    border-radius: 8px;
}

.navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 20px;
}

.nav-button {
    background: var(--accent-color);
    color: white;
    padding: 8px 20px;
    border-radius: 15px;
    text-decoration: none;
    transition: opacity 0.3s;
}

.nav-button-no {
    background: var();
    color: white;
    padding: 8px 20px;
    border-radius: 15px;
    text-decoration: none;
    transition: opacity 0.3s;
}

.nav-text{
    font-size: 1.5rem;
}

.nav-button:hover {
    opacity: 0.8;
}

.task-title {
    color: var(--primary-color);
    text-align: center;
    margin-bottom: 30px;
}

@media (max-width: 600px) {
    .answer-grid {
        grid-template-columns: 1fr;
    }
}