/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f5f5f5;
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
}

/* Header Styles */
header {
    text-align: center;
    color: #333;
    margin-bottom: 40px;
    padding: 30px 20px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    border-bottom: 3px solid #2196F3;
}

header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    color: #2196F3;
}

.subtitle {
    font-size: 1.2em;
    color: #666;
}

/* Problem Card Styles */
.problem-card {
    background: white;
    border-radius: 8px;
    padding: 30px;
    margin-bottom: 25px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    border: 1px solid #e0e0e0;
}

.problem-card h2 {
    color: #2196F3;
    margin-bottom: 10px;
    font-size: 1.5em;
}

.description {
    color: #666;
    margin-bottom: 20px;
    font-size: 0.95em;
}

/* Input Group Styles */
.input-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

input[type="number"],
input[type="text"],
select {
    flex: 1;
    min-width: 150px;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1em;
    transition: border-color 0.3s ease;
}

input[type="number"]:focus,
input[type="text"]:focus,
select:focus {
    outline: none;
    border-color: #2196F3;
}

button {
    padding: 12px 25px;
    background: #2196F3;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
}

button:hover {
    background: #1976D2;
}

button:active {
    background: #0D47A1;
}

/* Result Styles */
.result {
    background: #f8f9fa;
    border-left: 4px solid #2196F3;
    padding: 15px;
    border-radius: 8px;
    min-height: 50px;
    font-size: 0.95em;
    color: #333;
    line-height: 1.8;
}

.result:empty {
    display: none;
}

.result strong {
    color: #2196F3;
}

/* Counter Display */
.counter-display {
    text-align: center;
    margin: 20px 0;
}

.counter-display h3 {
    font-size: 4em;
    color: #2196F3;
    font-weight: bold;
}

/* Button Group */
.button-group {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
}

.button-group button {
    flex: 1;
    min-width: 120px;
}

/* Footer Styles */
footer {
    text-align: center;
    color: #666;
    margin-top: 40px;
    padding: 20px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    border-top: 3px solid #2196F3;
}

footer p {
    font-size: 1em;
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2em;
    }

    .subtitle {
        font-size: 1em;
    }

    .problem-card {
        padding: 20px;
    }

    .input-group {
        flex-direction: column;
    }

    input[type="number"],
    input[type="text"],
    select,
    button {
        width: 100%;
        min-width: 100%;
    }

    .counter-display h3 {
        font-size: 3em;
    }

    .button-group {
        flex-direction: column;
    }

    .button-group button {
        width: 100%;
    }
}