:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --card-bg: rgba(255, 255, 255, 0.95);
    --text-color: #1f2937;
    --text-secondary: #6b7280;
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}
body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    background: var(--bg-gradient);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0;
    padding: 20px;
    color: var(--text-color);
}
.container {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px;
    width: 100%;
    max-width: 500px;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(10px);
}
h1 {
    text-align: center;
    font-size: 1.8rem;
    margin-bottom: 30px;
    color: #111827;
    font-weight: 700;
}
.input-group {
    margin-bottom: 20px;
}
label {
    display: block;
    margin-bottom: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}
input[type="number"], input[type="text"] {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid #e5e7eb;
    border-radius: 10px;
    font-size: 1.1rem; /* Slightly larger font */
    transition: all 0.2s;
    box-sizing: border-box;
}

select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid #e5e7eb;
    border-radius: 10px;
    font-size: 1.1rem; /* Slightly larger font */
    transition: all 0.2s;
    box-sizing: border-box;
    -webkit-appearance: none; /* Remove default select arrow */
    -moz-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3e%3cpath fill='none' stroke='%23343a40' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M2 5l6 6 6-6'/%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 16px 12px;
}

select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.row {
    display: flex;
    gap: 15px;
}
.row .input-group {
    flex: 1;
}
button {
    width: 100%;
    padding: 14px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-top: 10px;
}
button:hover {
    background-color: var(--primary-hover);
}
#resultContainer {
    margin-top: 30px;
    padding: 20px;
    background-color: #f8fafc;
    border-radius: 12px;
    border: 1px solid #e2e8f0;
    display: none; /* Initially hidden */
}
.result-title {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}
.result-value {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    word-break: break-all;
    line-height: 1.4;
}
.error-msg {
    color: #ef4444;
    font-size: 0.9rem;
    margin-top: 5px;
    display: none;
}

.helper-text {
    font-size: 0.8rem;
    color: #9ca3af;
    margin-top: 4px;
}