:root {
    --primary-color: #007bff; /* Blue for actions */
    --tech-green: #0f0;     /* Matrix/Geek Green */
    --bg-color: #f8f9fa;
    --text-color: #212529;
    --card-bg: #ffffff;
    --border-color: #dee2e6;
    --font-mono: 'Roboto Mono', 'Fira Code', Consolas, monospace;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --spacing-unit: 1rem;
}

@media (prefers-color-scheme: dark) {
    :root {
        --primary-color: #0d6efd;
        --tech-green: #20c20e;
        --bg-color: #121212;
        --text-color: #e0e0e0;
        --card-bg: #1e1e1e;
        --border-color: #333;
    }
}

* {
    box-sizing: border-box;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

/* Typography */
h1, h2, h3 {
    margin-top: 0;
    font-weight: 700;
}

h1 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

a {
    color: var(--primary-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* Layout */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 var(--spacing-unit);
}

header {
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    margin-bottom: 2rem;
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    gap: 1.5rem;
    overflow-x: auto;
}

nav a {
    font-weight: 600;
    white-space: nowrap;
}

/* Converter Box */
.converter-box {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

textarea {
    width: 100%;
    min-height: 150px;
    padding: 1rem;
    font-family: var(--font-mono);
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--bg-color);
    color: var(--text-color);
    resize: vertical;
    transition: border-color 0.2s;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.25);
}

textarea.error {
    border-color: #dc3545;
}

.error-msg {
    color: #dc3545;
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: none;
}

.controls {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
    font-weight: 600;
    border-radius: 4px;
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.2s;
    background-color: var(--bg-color);
    color: var(--text-color);
    border-color: var(--border-color);
}

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

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: #0b5ed7;
}

/* SEO Content */
.content-section {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 3rem;
}

/* Utilities */
.text-mono {
    font-family: var(--font-mono);
}

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