:root {
    /* Dark Theme (Default) */
    --bg-color: #0d1117;
    --card-bg: #161b22;
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --accent-color: #58a6ff;
    --accent-hover: #1f6feb;
    --border-color: #30363d;
    --error-color: #f85149;
    --code-bg: #0d1117;

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

[data-theme="light"] {
    --bg-color: #dedfe1;
    --card-bg: #f6f8fa;
    --text-primary: #24292f;
    --text-secondary: #57606a;
    --accent-color: #0969da;
    --accent-hover: #0550ae;
    --border-color: #d0d7de;
    --error-color: #cf222e;
    --code-bg: #ffffff;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-primary);
    display: flex;
    justify-content: center;
    height: 100vh;
    overflow: hidden;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    width: 100%;
    max-width: 1200px;
    padding: 2rem 2rem 1rem 2rem;
    display: flex;
    flex-direction: column;
    height: 100%;
    gap: 1rem;
}

header {
    margin-bottom: 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    font-weight: 700;
    font-size: 1.8rem;
    letter-spacing: -0.5px;
    background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

header p {
    color: var(--text-secondary);
    font-size: 1rem;
}

.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 8px;
    border-radius: 50%;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.icon-btn:hover {
    background-color: rgba(110, 118, 129, 0.1);
    color: var(--text-primary);
}

.sun-icon {
    display: none;
}

.moon-icon {
    display: block;
}

[data-theme="light"] .sun-icon {
    display: block;
}

[data-theme="light"] .moon-icon {
    display: none;
}

main {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    /* Side by side */
    gap: 2rem;
    min-height: 0;
    /* Important for nested scrolling */
}

.main-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    min-height: 0;
    overflow-y: auto;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    justify-content: center;
    height: 100%;
    overflow-y: auto;
    /* Allow input side to scroll if needed, though unlikely */
}

label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.input-wrapper {
    display: flex;
    gap: 10px;
}

input[type="text"] {
    flex: 1;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 12px 16px;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s, background-color 0.3s;
}

input[type="text"]:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.15);
}

button {
    cursor: pointer;
    border: none;
    border-radius: 8px;
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    white-space: nowrap;
}

.primary-btn {
    background-color: var(--accent-color);
    color: #ffffff;
    padding: 0 24px;
}

.primary-btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
}

.primary-btn:active {
    transform: translateY(0);
}

.secondary-btn {
    background-color: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 6px 12px;
    font-size: 0.85rem;
}

.secondary-btn:hover {
    color: var(--text-primary);
    border-color: var(--text-secondary);
    background-color: rgba(110, 118, 129, 0.1);
}

.secondary-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

.options-group {
    display: flex;
    gap: 1.5rem;
    margin-top: 0.5rem;
}

.checkbox-wrapper {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    user-select: none;
}

.checkbox-wrapper input[type="checkbox"] {
    appearance: none;
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--card-bg);
    cursor: pointer;
    position: relative;
    transition: all 0.2s ease;
}

.checkbox-wrapper input[type="checkbox"]:checked {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

.checkbox-wrapper input[type="checkbox"]:checked::after {
    content: "";
    position: absolute;
    left: 5px;
    top: 2px;
    width: 4px;
    height: 8px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.checkbox-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.checkbox-wrapper:hover .checkbox-label {
    color: var(--text-primary);
}

.error-message {
    color: var(--error-color);
    font-size: 0.9rem;
    min-height: 1.5em;
    opacity: 0;
    transition: opacity 0.2s;
}

.error-message.visible {
    opacity: 1;
}

.feature-info {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    margin-top: 12px;
    padding: 12px;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.feature-info svg {
    flex-shrink: 0;
    margin-top: 2px;
    color: var(--accent-color);
}

.feature-info a {
    color: var(--accent-color);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s;
}

.feature-info a:visited {
    color: var(--accent-color);
}

.feature-info a:hover {
    border-bottom-color: var(--accent-color);
}

.output-group {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    height: 100%;
    /* Fill height */
    max-height: 100%;
    transition: background-color 0.3s, border-color 0.3s;
    overflow: hidden;
    /* Ensure no scroll on container */
}



.output-header {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 12px;
    flex-shrink: 0;
}

.output-header > label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.output-actions {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: nowrap;
}

.font-size-control {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    flex-shrink: 0;
    white-space: nowrap;
    margin-left: 0;
}

.font-size-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    white-space: nowrap;
    flex-shrink: 0;
}

.font-size-slider {
    width: 70px;
    height: 4px;
    background: var(--border-color);
    border-radius: 2px;
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    flex-shrink: 0;
}

.font-size-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px;
    height: 14px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
    transition: background 0.2s;
}

.font-size-slider::-webkit-slider-thumb:hover {
    background: var(--accent-hover);
}

.font-size-slider::-moz-range-thumb {
    width: 14px;
    height: 14px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
    border: none;
    transition: background 0.2s;
}

.font-size-slider::-moz-range-thumb:hover {
    background: var(--accent-hover);
}

.font-size-value {
    font-size: 0.85rem;
    color: var(--text-secondary);
    min-width: 45px;
    font-family: var(--font-mono);
    flex-shrink: 0;
    text-align: left;
}

.checkbox-wrapper.small {
    gap: 6px;
}

.checkbox-wrapper.small input[type="checkbox"] {
    width: 16px;
    height: 16px;
}

.checkbox-wrapper.small .checkbox-label {
    font-size: 0.85rem;
}

.code-wrapper {
    background-color: var(--code-bg);
    border-radius: 8px;
    padding: 16px;
    border: 1px solid var(--border-color);
    flex: 1;
    overflow-y: auto;
    /* Scroll inside the code block */
    position: relative;
    min-height: 0;
    /* Crucial for flex child scrolling */
    transition: background-color 0.3s, border-color 0.3s;
}

.code-copy-btn {
    position: absolute;
    top: 12px;
    right: 12px;
    z-index: 10;
    padding: 6px 12px;
    font-size: 0.85rem;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.code-copy-btn:hover {
    background-color: var(--bg-color);
    border-color: var(--text-secondary);
}

code {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    white-space: pre-wrap;
    /* Wrap long lines */
    word-break: break-all;
    color: var(--text-primary);
    outline: none;
    display: block;
    min-height: 100px;
}

code[contenteditable="true"] {
    cursor: text;
}

code[contenteditable="true"]:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: -2px;
    border-radius: 4px;
}

code.placeholder {
    color: var(--text-secondary);
    font-style: italic;
    opacity: 0.7;
}

code.placeholder[contenteditable="true"]:focus {
    opacity: 1;
    font-style: normal;
    color: var(--text-primary);
}

.hidden {
    display: none;
    /* Still needed for initial state logic in JS, but we might want to revisit if we want to reserve space */
}

/* Override hidden for grid layout stability if we want it to just be invisible but take space? 
   No, let's keep it hidden until needed, but on desktop it will just pop into the right column.
*/

footer {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.85rem;
    flex-shrink: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    padding-bottom: 0;
}

footer p {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-wrap: wrap;
    justify-content: center;
}

footer a {
    color: var(--text-primary);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s;
}

footer a:visited {
    color: var(--text-primary);
}

footer a:hover {
    border-bottom-color: var(--text-primary);
}

.github-link {
    color: var(--text-secondary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: color 0.2s;
    margin-left: 8px;
    border-bottom: none !important;
}

.github-link:visited {
    color: var(--text-secondary);
}

.github-link:hover {
    color: var(--accent-color);
}

/* Loading state */
.primary-btn.loading span {
    display: none;
}

.primary-btn.loading::after {
    content: "";
    width: 16px;
    height: 16px;
    border: 2px solid #ffffff;
    border-top-color: transparent;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.pagination-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin: 12px 0;
    padding: 12px 0;
    border-top: 1px solid var(--border-color);
    flex-shrink: 0;
}

.page-info {
    font-size: 0.9rem;
    color: var(--text-secondary);
    min-width: 150px;
    text-align: center;
}

.pagination-btn {
    min-width: 80px;
}

/* Mobile Optimization */
@media (max-width: 768px) {
    body {
        height: 100vh;
        /* Fixed height on mobile too */
        overflow: hidden;
    }

    .container {
        padding: 1rem;
        height: 100%;
    }

    main {
        display: flex;
        flex-direction: column;
        gap: 1rem;
    }
    
    .main-content {
        grid-template-columns: 1fr !important;
    }

    .input-group {
        justify-content: flex-start;
        height: auto;
        flex-shrink: 0;
        /* Don't shrink input area */
    }

    .output-group {
        height: auto;
        flex: 1;
        /* Take remaining space */
        min-height: 0;
        /* Allow shrinking to fit */
    }

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

    .primary-btn {
        width: 100%;
        padding: 12px;
    }

    .output-actions {
        gap: 10px;
        justify-content: flex-end;
        flex-wrap: nowrap;
    }
    
    .font-size-control {
        gap: 4px;
    }
    
    .font-size-slider {
        width: 60px;
    }
    
    .font-size-value {
        min-width: 40px;
        font-size: 0.8rem;
    }
    
    .font-size-label {
        font-size: 0.8rem;
    }
}