:root {
    --deiso-green: #63a34e;
    --deiso-green-hover: #4f833d;
    
    /* Default to Dark Theme Variables */
    --background-color: #1a1a1a;
    --text-color: #ffffff;
    --border-color: #404040;
    --shadow-color: rgba(0, 0, 0, 0.3);
}

/* Light Theme Overrides */
body[data-theme="light"] {
    --background-color: #ffffff;
    --text-color: #333333;
    --border-color: #e0e0e0;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease; /* Add transition for smoother theme change */
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    background-color: var(--background-color);
    border-radius: 12px;
    box-shadow: 0 4px 6px var(--shadow-color);
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

h1 {
    color: var(--deiso-green);
    font-size: 2rem;
    margin-bottom: 1rem;
}

.converter {
    background-color: var(--background-color);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px var(--shadow-color);
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.select-input,
.number-input {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--background-color);
    color: var(--text-color);
    font-size: 1rem;
    transition: border-color 0.3s ease, background-color 0.3s ease, color 0.3s ease;
}

.select-input:focus,
.number-input:focus {
    outline: none;
    border-color: var(--deiso-green);
}

.convert-btn {
    width: 100%;
    padding: 1rem;
    background-color: var(--deiso-green);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.convert-btn:hover {
    background-color: var(--deiso-green-hover);
}

.result-container {
    margin-top: 2rem;
    padding: 1.5rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    text-align: center;
    background-color: var(--background-color);
}

.result {
    font-size: 2rem;
    font-weight: 600;
    margin: 1rem 0;
    color: var(--deiso-green);
}

.copy-btn {
    padding: 0.5rem 1rem;
    background-color: transparent;
    border: 2px solid var(--deiso-green);
    color: var(--deiso-green);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.copy-btn:hover {
    background-color: var(--deiso-green);
    color: white;
}

footer {
    text-align: center;
    margin-top: 2rem;
    color: var(--text-color);
    opacity: 0.8;
}

.error-message {
    margin-top: 1rem;
    padding: 1rem;
    background-color: #ffebee;
    border: 2px solid #ffcdd2;
    border-radius: 8px;
    color: #c62828;
    text-align: center;
    font-weight: 500;
}

body[data-theme="dark"] .error-message {
    background-color: #311b1b;
    border-color: #4a1c1c;
    color: #ff8a80;
}

@media (max-width: 600px) {
    .container {
        padding: 1rem;
    }
    
    .converter {
        padding: 1.5rem;
    }
    
    h1 {
        font-size: 1.5rem;
    }
}