:root {
    /* Light theme variables */
    --bg-color: #f8f9fa;
    --text-color: #212529;
    --editor-bg: #ffffff;
    --line-number-bg: #f1f3f5;
    --line-number-color: #868e96;
    --header-bg: #ffffff;
    --border-color: #dee2e6;
    --btn-bg: #e9ecef;
    --btn-hover: #ced4da;
    --accent-color: #228be6;
    --notification-bg: #d3f9d8;
    --notification-text: #2b8a3e;
    --editor-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

[data-theme='dark'] {
    /* Dark theme variables */
    --bg-color: #212529;
    --text-color: #f8f9fa;
    --editor-bg: #343a40;
    --line-number-bg: #2b3035;
    --line-number-color: #adb5bd;
    --header-bg: #343a40;
    --border-color: #495057;
    --btn-bg: #495057;
    --btn-hover: #6c757d;
    --accent-color: #74c0fc;
    --notification-bg: #0b7285;
    --notification-text: #e3fafc;
    --editor-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
}

header {
    background-color: var(--header-bg);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    margin-bottom: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
}

.controls {
    display: flex;
    gap: 0.75rem;
}

.control-btn {
    background-color: var(--btn-bg);
    border: none;
    color: var(--text-color);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    transition: background-color 0.2s;
}

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

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    transition: background-color 0.2s;
}

.theme-toggle:hover {
    background-color: var(--btn-bg);
}

.editor-container {
    display: flex;
    border-radius: 6px;
    overflow: hidden;
    box-shadow: var(--editor-shadow);
    background-color: var(--editor-bg);
    height: calc(100vh - 200px);
    min-height: 400px;
}

.line-numbers {
    background-color: var(--line-number-bg);
    color: var(--line-number-color);
    padding: 1rem 0.5rem;
    text-align: right;
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    min-width: 3.5rem;
    user-select: none;
    overflow-y: hidden;
    border-right: 1px solid var(--border-color);
}

.line-numbers div {
    padding: 0 0.5rem;
    height: 1.5rem;
}

#editor, #viewer {
    flex-grow: 1;
    padding: 1rem;
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    background-color: var(--editor-bg);
    color: var(--text-color);
    border: none;
    resize: none;
    outline: none;
    white-space: pre;
    overflow-y: auto;
    tab-size: 4;
    line-height: 1.5rem;
    height: 100%;
}

#viewer {
    display: none;
}

.viewer-active #editor {
    display: none;
}

.viewer-active #viewer {
    display: block;
}

.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 0.75rem 1.25rem;
    background-color: var(--notification-bg);
    color: var(--notification-text);
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, opacity 0.3s;
    transform: translateY(-10px);
    opacity: 0;
    pointer-events: none;
}

.notification.show {
    transform: translateY(0);
    opacity: 1;
}

.footer {
    text-align: center;
    padding: 1rem 0;
    margin-top: 1.5rem;
    font-size: 0.9rem;
    color: var(--line-number-color);
}

.language-selector {
    padding: 0.5rem;
    background-color: var(--btn-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 0.9rem;
}

/* For mobile responsiveness */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }

    .controls {
        width: 100%;
        justify-content: center;
        flex-wrap: wrap;
    }

    .editor-container {
        height: calc(100vh - 260px);
    }
}