:root {
    --bg-app: #0f1115;
    --bg-panel: #161b22;
    --bg-input: #0d1117;
    --border-color: #30363d;
    --accent-color: #58a6ff;
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --font-ui: 'Inter', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    --header-height: 60px;
    --pane-header-height: 40px;
}

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

body {
    font-family: var(--font-ui);
    background-color: var(--bg-app);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.app-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-panel);
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--text-primary);
}

.logo svg {
    color: var(--accent-color);
}

.logo h1 {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.5px;
}

.icon-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 8px;
    border-radius: 6px;
    transition: all 0.2s ease;
}

.icon-btn:hover {
    color: var(--text-primary);
    background-color: rgba(255, 255, 255, 0.05);
}

.workspace {
    display: flex;
    flex: 1;
    overflow: hidden;
}

.editor-pane,
.preview-pane {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.editor-pane {
    border-right: 1px solid var(--border-color);
}

.pane-header {
    height: var(--pane-header-height);
    padding: 0 16px;
    display: flex;
    align-items: center;
    background-color: var(--bg-panel);
    border-bottom: 1px solid var(--border-color);
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.editor-wrapper,
.preview-wrapper {
    flex: 1;
    position: relative;
    background-color: var(--bg-input);
}

#html-input {
    width: 100%;
    height: 100%;
    background-color: var(--bg-input);
    color: var(--text-primary);
    border: none;
    padding: 16px;
    font-family: var(--font-mono);
    font-size: 14px;
    line-height: 1.5;
    resize: none;
    outline: none;
}

#preview-frame {
    width: 100%;
    height: 100%;
    border: none;
    background-color: #ffffff;
    /* Preview needs to be white by default usually */
}

@media (max-width: 768px) {
    .workspace {
        flex-direction: column;
    }

    .editor-pane {
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        height: 50%;
    }
}

.app-footer {
    height: 30px;
    background-color: var(--bg-panel);
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.app-footer a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s;
}

.app-footer a:hover {
    color: var(--accent-color);
    text-decoration: underline;
}