style.css

:root {
    --editor-background: #212121;
    --pane-background: #ffffff;
    --border-color: #e4e4e7;
    --header-color: #3f3f46;
    --bg-color: #fafafa;
    --bg-gradient: linear-gradient(135deg, #fafafa 0%, #f8f8fa 50%, #f5f5f7 100%);
    --text-color: #27272a;
    --main-header-bg: linear-gradient(135deg, #ffffff 0%, #fafafa 100%);
    --main-header-text: #18181b;
    --input-bg: #ffffff;
    --loader-bg: rgba(255, 255, 255, 0.95);
    --overlay-bg: rgba(250, 250, 250, 0.85);
    --whitespace-color: #71717a;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --success-color: #10b981;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --gradient-border: linear-gradient(135deg, rgba(59, 130, 246, 0.15), rgba(139, 92, 246, 0.1), rgba(236, 72, 153, 0.15));
    --btn-background: #f4f4f5;
    --btn-hover: #e4e4e7;
    --btn-text: #27272a;
}

/* Dark mode theme */
body.dark-mode {
    --editor-background: #212121;
    --pane-background: #18181b;
    --border-color: #3f3f46;
    --header-color: #d4d4d8;
    --bg-color: #09090b;
    --bg-gradient: linear-gradient(135deg, #09090b 0%, #0f0f12 50%, #18181b 100%);
    --text-color: #e4e4e7;
    --main-header-bg: linear-gradient(135deg, #18181b 0%, #27272a 100%);
    --main-header-text: #fafafa;
    --input-bg: #27272a;
    --loader-bg: rgba(24, 24, 27, 0.95);
    --overlay-bg: rgba(9, 9, 11, 0.85);
    --whitespace-color: #a1a1aa;
    --accent-color: #3b82f6;
    --accent-hover: #60a5fa;
    --success-color: #10b981;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.4);
    --gradient-border: linear-gradient(135deg, rgba(59, 130, 246, 0.25), rgba(139, 92, 246, 0.15), rgba(236, 72, 153, 0.25));
    --btn-background: #27272a;
    --btn-hover: #3f3f46;
    --btn-text: #e4e4e7;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    background: var(--bg-gradient);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    height: 100vh;
    transition: background 0.3s ease;
}

/* Main Header Styling */
.main-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--main-header-bg);
    border-bottom: 1px solid transparent;
    padding: 14px 24px;
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
    position: relative;
}

.main-header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--gradient-border);
    opacity: 0.4;
}

.main-header h1 {
    margin: 0;
    color: var(--main-header-text);
    font-weight: 600;
    font-size: 19px;
    letter-spacing: -0.02em;
}

.theme-toggle-container {
    display: flex;
    align-items: center;
    gap: 10px;
}

.theme-label {
    font-size: 12px;
    color: var(--text-color);
    font-weight: 500;
}

.theme-switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}

.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.theme-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #d4d4d8;
    transition: all 0.3s ease;
    border-radius: 24px;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.1);
}

.theme-slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
}

.theme-switch input:checked + .theme-slider {
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--accent-hover) 100%);
}

.theme-switch input:checked + .theme-slider:before {
    transform: translateX(20px);
}
.container {
    display: flex;
    flex-grow: 1;
    gap: 14px;
    padding: 14px;
    min-width: 0; /* Allow flex shrinking */
    overflow: hidden;
}
.left-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 14px;
    height: calc(100vh - 98px); /* Adjusted for header */
    min-width: 0; /* Allow flex shrinking */
    overflow: hidden;
}
.right-panel {
    flex: 1;
    height: calc(100vh - 98px); /* Adjusted for header */
    min-width: 0; /* Allow flex shrinking */
    overflow: hidden;
}
.pane {
    display: flex;
    flex-direction: column;
    background: var(--pane-background);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    min-height: 0; /* Allow flex items to shrink */
    min-width: 0; /* Allow flex items to shrink horizontally */
    width: 100%;
    transition: box-shadow 0.3s ease, transform 0.2s ease;
    animation: fadeInUp 0.4s ease-out;
    position: relative;
    background-clip: padding-box;
}

.pane::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 10px;
    padding: 1px;
    background: var(--gradient-border);
    -webkit-mask: 
        linear-gradient(#fff 0 0) content-box, 
        linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask: 
        linear-gradient(#fff 0 0) content-box, 
        linear-gradient(#fff 0 0);
    mask-composite: exclude;
    pointer-events: none;
    opacity: 0.5;
    transition: opacity 0.3s ease;
}

.pane:hover {
    box-shadow: var(--shadow-lg);
}

.pane:hover::before {
    opacity: 1;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}
.template-pane {
    flex: 2;
    min-height: 0;
    animation-delay: 0.05s;
}
.variables-pane {
    flex: 1;
    min-height: 0;
    animation-delay: 0.1s;
}
#output-pane {
    animation-delay: 0.15s;
}
.pane h2 {
    margin: 0;
    padding: 14px 16px;
    font-size: 13px;
    background: var(--pane-background);
    border-bottom: 1px solid var(--border-color);
    color: var(--header-color);
    font-weight: 600;
    letter-spacing: -0.01em;
    position: relative;
    z-index: 1;
}
.pane-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--pane-background);
    border-bottom: 1px solid var(--border-color);
    padding: 14px 16px;
    transition: background 0.2s ease;
    position: relative;
    z-index: 1;
}
.pane-header h2 {
    margin: 0;
    padding: 0;
    border-bottom: none;
    background: none;
    font-size: 13px;
}
.pane-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--pane-background);
    border-top: 1px solid var(--border-color);
    padding: 14px 16px;
    transition: background 0.2s ease;
    position: relative;
    z-index: 1;
}
.footer-controls-left {
    display: flex;
    align-items: center;
    gap: 12px;
}
.footer-controls-right {
    display: flex;
    align-items: center;
    gap: 12px;
}
.header-controls {
    display: flex;
    align-items: center;
    gap: 12px;
}
.control-group {
    display: flex;
    align-items: center;
    gap: 8px;
}
.switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}
.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}
.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #d4d4d8;
    transition: all 0.3s ease;
    border-radius: 24px;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.1);
}
.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
}
input:checked + .slider {
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--accent-hover) 100%);
}
input:checked + .slider:before {
    transform: translateX(20px);
}
.rerender-btn {
    padding: 5.5px 14px;
    background: var(--btn-background);
    color: var(--btn-text);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    font-size: 12px;
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
    position: relative;
    top: 0;
}
.rerender-btn:hover {
    background: var(--btn-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.12), 0 2px 4px rgba(0, 0, 0, 0.08);
}
.rerender-btn:active {
    transform: translateY(0);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}
.rerender-btn:disabled {
    background: var(--border-color);
    color: #a1a1aa;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
    opacity: 0.5;
}
.control-label {
    font-size: 12px;
    color: var(--header-color);
    font-weight: 500;
}
.header-btn {
    padding: 6px 12px;
    background: var(--btn-background);
    color: var(--btn-text);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    font-size: 11px;
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
    position: relative;
}
.header-btn:hover {
    background: var(--btn-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.12), 0 2px 4px rgba(0, 0, 0, 0.08);
}
.header-btn:active {
    transform: translateY(0);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}
.CodeMirror {
    flex-grow: 1;
    height: auto;
    font-size: 12px;
    min-height: 0;
    width: 100%;
    max-width: 100%;
    border-radius: 0;
    position: relative;
    z-index: 1;
}
.CodeMirror-scroll {
    overflow-x: auto !important;
    overflow-y: auto !important;
    max-width: 100%;
}
.CodeMirror-lines {
    max-width: 100%;
    padding: 8px 0;
}
#output-pane {
    height: 100%;
    min-height: 0;
    display: flex;
    flex-direction: column;
}
.output-content {
    flex-grow: 1;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    min-height: 0;
    position: relative;
    z-index: 1;
}
#output {
    flex-grow: 1;
    padding: 18px;
    white-space: pre-wrap;
    word-wrap: break-word;
    overflow: auto;
    font-family: "Menlo", "Consolas", monospace;
    font-size: 12px;
    line-height: 1.7;
    min-height: 0;
    position: relative;
    z-index: 1;
}
.error {
    color: #ef4444;
    font-weight: 600;
    background: rgba(239, 68, 68, 0.1);
    padding: 12px;
    border-radius: 6px;
    border-left: 3px solid #ef4444;
}
.variable-input {
    margin-bottom: 15px;
    position: relative;
    z-index: 1;
}
.variable-input label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    color: var(--header-color);
    font-size: 12px;
}
.variable-input input, .variable-input textarea {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 12px;
    font-family: "Menlo", "Consolas", monospace;
    background: var(--input-bg);
    color: var(--text-color);
    box-sizing: border-box;
    transition: all 0.2s ease;
}
.variable-input textarea {
    min-height: 60px;
    resize: vertical;
}
.variable-input input:focus, .variable-input textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}
.variable-input input:hover, .variable-input textarea:hover {
    border-color: var(--accent-color);
}
.form-mode-toggle {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 12px;
    background: var(--pane-background);
    border-bottom: 1px solid var(--border-color);
    font-size: 12px;
}
.mode-switch {
    background: var(--btn-background);
    color: var(--btn-text);
    cursor: pointer;
    text-decoration: none;
    font-size: 11px;
    padding: 6px 12px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
    position: relative;
}
.mode-switch:hover {
    background: var(--btn-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.12), 0 2px 4px rgba(0, 0, 0, 0.08);
}
.mode-switch:active {
    transform: translateY(0);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}

/* Resize handles */
.resize-handle {
    background: transparent;
    transition: all 0.3s ease;
    position: relative;
}
.resize-handle:hover {
    background: rgba(59, 130, 246, 0.15);
}
.resize-handle:active {
    background: rgba(59, 130, 246, 0.3);
}
.resize-handle-horizontal {
    height: 4px;
    cursor: row-resize;
    width: 100%;
}
.resize-handle-vertical {
    width: 4px;
    cursor: col-resize;
    height: 100%;
}

/* Container adjustments for resizing */
.resizable-container {
    display: flex;
    flex-grow: 1;
    gap: 0;
    padding: 14px;
    min-width: 0;
    box-sizing: border-box; /* Include padding in height calculation */
    overflow: hidden; /* Prevent container from overflowing */
}
.resizable-left-panel {
    display: flex;
    flex-direction: column;
    gap: 0;
    min-width: 200px;
    max-width: calc(100vw - 250px);
    height: 100%; /* Use full container height */
}
.resizable-right-panel {
    min-width: 200px;
    height: 100%; /* Use full container height */
}
.resizable-template-pane {
    min-height: 100px;
    overflow: hidden;
}
.resizable-variables-pane {
    min-height: 100px;
    overflow: hidden;
}

/* Loading state */
#loader {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 1.2em;
    background: var(--loader-bg);
    color: var(--text-color);
    padding: 24px 32px;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    display: none;
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    font-weight: 500;
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--overlay-bg);
    z-index: 999;
    display: none;
    backdrop-filter: blur(8px);
}

/* --- UPDATED WHITESPACE STYLING --- */
.whitespace-char {
    /* Use relative positioning to anchor the pseudo-element */
    position: relative;
}
.whitespace-char::before {
    /* Position the symbol absolutely so it doesn't affect layout */
    position: absolute;
    color: var(--whitespace-color);
    opacity: 0.6;
    /* Prevent the symbols from being selected with the text */
    pointer-events: none;
}
.whitespace-char.space::before {
    content: '·';
}
.whitespace-char.tab::before {
    content: '→';
}
.whitespace-char.newline::before {
    content: '↵';
}

/* --- MARKDOWN CONTENT STYLING --- */
.markdown-content {
    flex-grow: 1;
    padding: 24px;
    overflow: auto;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 14px;
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--pane-background);
    min-height: 0;
}

.markdown-content h1,
.markdown-content h2,
.markdown-content h3,
.markdown-content h4,
.markdown-content h5,
.markdown-content h6 {
    margin-top: 24px;
    margin-bottom: 16px;
    font-weight: 600;
    line-height: 1.25;
    color: var(--text-color);
}

.markdown-content h1 {
    font-size: 2em;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.3em;
}

.markdown-content h2 {
    font-size: 1.5em;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.3em;
}

.markdown-content h3 {
    font-size: 1.25em;
}

.markdown-content h4 {
    font-size: 1em;
}

.markdown-content h5 {
    font-size: 0.875em;
}

.markdown-content h6 {
    font-size: 0.85em;
    color: var(--header-color);
}

.markdown-content p {
    margin-top: 0;
    margin-bottom: 16px;
}

.markdown-content a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

.markdown-content ul,
.markdown-content ol {
    margin-top: 0;
    margin-bottom: 16px;
    padding-left: 2em;
}

.markdown-content li {
    margin-top: 0.25em;
}

.markdown-content blockquote {
    margin: 0 0 16px 0;
    padding: 0 1em;
    color: var(--header-color);
    border-left: 4px solid var(--border-color);
}

.markdown-content code {
    padding: 0.2em 0.4em;
    margin: 0;
    font-size: 85%;
    background-color: rgba(127, 127, 127, 0.2);
    border-radius: 3px;
    font-family: "Menlo", "Consolas", monospace;
}

.markdown-content pre {
    padding: 16px;
    overflow: auto;
    font-size: 85%;
    line-height: 1.45;
    background-color: rgba(127, 127, 127, 0.15);
    border-radius: 6px;
    margin-bottom: 16px;
}

.markdown-content pre code {
    display: inline;
    padding: 0;
    margin: 0;
    overflow: visible;
    line-height: inherit;
    background-color: transparent;
    border: 0;
}

.markdown-content table {
    border-spacing: 0;
    border-collapse: collapse;
    margin-top: 0;
    margin-bottom: 16px;
    width: 100%;
    overflow: auto;
}

.markdown-content table th,
.markdown-content table td {
    padding: 6px 13px;
    border: 1px solid var(--border-color);
}

.markdown-content table th {
    font-weight: 600;
    background-color: rgba(127, 127, 127, 0.1);
}

.markdown-content table tr {
    background-color: var(--pane-background);
    border-top: 1px solid var(--border-color);
}

.markdown-content table tr:nth-child(2n) {
    background-color: rgba(127, 127, 127, 0.05);
}

.markdown-content img {
    max-width: 100%;
    box-sizing: content-box;
}

.markdown-content hr {
    height: 0.25em;
    padding: 0;
    margin: 24px 0;
    background-color: var(--border-color);
    border: 0;
}

.markdown-content strong {
    font-weight: 600;
}

.markdown-content em {
    font-style: italic;
}

/* Mermaid diagram styling */
.markdown-content .mermaid {
    background-color: transparent;
    margin: 16px 0;
    text-align: center;
}

/* Dark mode specific adjustments for better mermaid visibility */
body.dark-mode .markdown-content .mermaid svg {
    background-color: transparent;
}

/* Mermaid text wrapping support */
/* Target the actual node shapes */
.markdown-content .mermaid .node rect,
.markdown-content .mermaid .node circle,
.markdown-content .mermaid .node ellipse,
.markdown-content .mermaid .node polygon,
.markdown-content .mermaid .node path {
    min-width: 100px !important;
}

.markdown-content .mermaid .node {
    min-width: 100px !important;
}

.markdown-content .mermaid .node .label,
.markdown-content .mermaid .edgeLabel .label {
    white-space: normal !important;
    word-wrap: break-word !important;
    overflow-wrap: break-word !important;
    min-width: 100px;
    max-width: 200px;
}

.markdown-content .mermaid .nodeLabel,
.markdown-content .mermaid .edgeLabel {
    white-space: normal !important;
    word-wrap: break-word !important;
    overflow-wrap: break-word !important;
    min-width: 100px;
    max-width: 200px;
}

.markdown-content .mermaid foreignObject {
    overflow: visible !important;
    min-width: 100px !important;
}

.markdown-content .mermaid foreignObject div {
    white-space: normal !important;
    word-wrap: break-word !important;
    overflow-wrap: break-word !important;
    min-width: 100px;
    max-width: 200px;
    padding: 5px;
}