/* === Reset & Base === */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg: #0f1117;
    --surface: #1a1d27;
    --border: #2e3345;
    --text: #e8eaed;
    --text-muted: #8b8fa3;
    --accent: #6c63ff;
    --accent-hover: #5a52e0;
    --success: #4caf50;
    --error: #f44336;
    --warning: #ff9800;
    --json-string: #98c379;
    --json-number: #e5c07b;
    --json-boolean: #61afef;
    --json-null: #8b8fa3;
    --json-key: #e8eaed;
    --diff-add: rgba(76, 175, 80, 0.15);
    --diff-remove: rgba(244, 67, 54, 0.15);
    --diff-change: rgba(255, 152, 0, 0.15);
    --diff-add-text: #4caf50;
    --diff-remove-text: #f44336;
    --diff-change-text: #ff9800;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
}

/* === Header === */
header {
    padding: 32px 0 16px;
    text-align: center;
}

header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 4px;
}

header .subtitle {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* === Tabs === */
.tabs {
    display: flex;
    gap: 4px;
    padding: 16px 16px 0;
    border-bottom: 1px solid var(--border);
    overflow-x: auto;
}

.tab {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 0.95rem;
    padding: 10px 20px;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: color 0.2s, border-color 0.2s;
    white-space: nowrap;
    font-family: inherit;
}

.tab:hover {
    color: var(--text);
}

.tab.active {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

/* === Tab Content === */
.tab-content {
    display: none;
    padding: 16px 0;
}

.tab-content.active {
    display: block;
}

/* === Toolbar === */
.toolbar {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}

.toolbar label {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.toolbar select {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 6px 10px;
    font-size: 0.85rem;
    font-family: inherit;
    cursor: pointer;
}

.toolbar select:focus {
    outline: none;
    border-color: var(--accent);
}

/* === Buttons === */
.btn-primary,
.btn-secondary,
.btn-small {
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.85rem;
    transition: background 0.2s, opacity 0.2s;
}

.btn-primary {
    background: var(--accent);
    color: #fff;
    padding: 8px 20px;
    font-weight: 600;
}

.btn-primary:hover {
    background: var(--accent-hover);
}

.btn-secondary {
    background: var(--surface);
    color: var(--text-muted);
    padding: 8px 16px;
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    color: var(--text);
    border-color: var(--text-muted);
}

.btn-small {
    background: var(--surface);
    color: var(--text-muted);
    padding: 4px 12px;
    border: 1px solid var(--border);
    font-size: 0.8rem;
}

.btn-small:hover {
    color: var(--text);
}

/* === Editor Layout === */
.editor-row {
    display: flex;
    gap: 12px;
}

.editor-col {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
}

.editor-col.full-width {
    flex: 1 1 100%;
}

.editor-col > label {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 4px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 4px;
}

.output-header label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.output-actions {
    display: flex;
    gap: 4px;
}

/* === Text Areas & Output === */
.code-input {
    width: 100%;
    min-height: 300px;
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", "Consolas", monospace;
    font-size: 0.85rem;
    line-height: 1.5;
    resize: vertical;
    tab-size: 2;
}

.code-input:focus {
    outline: none;
    border-color: var(--accent);
}

.code-input::placeholder {
    color: var(--text-muted);
}

.code-output {
    width: 100%;
    min-height: 300px;
    max-height: 600px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", "Consolas", monospace;
    font-size: 0.85rem;
    line-height: 1.5;
    overflow: auto;
    white-space: pre-wrap;
    word-wrap: break-word;
}

/* === Syntax Highlighting === */
.json-key { color: var(--json-key); font-weight: 600; }
.json-string { color: var(--json-string); }
.json-number { color: var(--json-number); }
.json-boolean { color: var(--json-boolean); }
.json-null { color: var(--json-null); font-style: italic; }
.json-bracket { color: var(--text-muted); }

/* === Validate Result === */
.validate-result {
    margin-top: 12px;
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 0.9rem;
    display: none;
}

.validate-result.valid {
    display: block;
    background: rgba(76, 175, 80, 0.1);
    border: 1px solid rgba(76, 175, 80, 0.3);
    color: var(--success);
}

.validate-result.invalid {
    display: block;
    background: rgba(244, 67, 54, 0.1);
    border: 1px solid rgba(244, 67, 54, 0.3);
    color: var(--error);
}

.validate-result .error-line {
    font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", "Consolas", monospace;
    font-size: 0.85rem;
    margin-top: 8px;
    padding: 8px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 4px;
    white-space: pre-wrap;
}

/* === Diff Output === */
.diff-output {
    margin-top: 12px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", "Consolas", monospace;
    font-size: 0.85rem;
    line-height: 1.6;
    max-height: 600px;
    overflow: auto;
    display: none;
    white-space: pre-wrap;
}

.diff-output.visible {
    display: block;
}

.diff-line {
    padding: 1px 8px;
    border-radius: 3px;
    margin: 1px 0;
}

.diff-add {
    background: var(--diff-add);
    color: var(--diff-add-text);
}

.diff-remove {
    background: var(--diff-remove);
    color: var(--diff-remove-text);
}

.diff-change {
    background: var(--diff-change);
    color: var(--diff-change-text);
}

.diff-same {
    color: var(--text-muted);
}

.diff-header {
    color: var(--accent);
    font-weight: 600;
    margin-bottom: 4px;
}

/* === Tree View === */
.tree-output {
    width: 100%;
    min-height: 300px;
    max-height: 600px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    overflow: auto;
    font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", "Consolas", monospace;
    font-size: 0.85rem;
    line-height: 1.6;
}

.tree-node {
    padding-left: 20px;
}

.tree-node-root {
    padding-left: 0;
}

.tree-toggle {
    cursor: pointer;
    user-select: none;
    display: inline-block;
    width: 16px;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.75rem;
}

.tree-toggle:hover {
    color: var(--accent);
}

.tree-key {
    color: var(--json-key);
    font-weight: 600;
}

.tree-colon {
    color: var(--text-muted);
}

.tree-value-string { color: var(--json-string); }
.tree-value-number { color: var(--json-number); }
.tree-value-boolean { color: var(--json-boolean); }
.tree-value-null { color: var(--json-null); font-style: italic; }

.tree-bracket {
    color: var(--text-muted);
}

.tree-children {
    overflow: hidden;
}

.tree-children.collapsed {
    display: none;
}

.tree-count {
    color: var(--text-muted);
    font-size: 0.75rem;
    font-style: italic;
}

/* === Ad Slot === */
.ad-slot {
    margin: 16px auto;
    text-align: center;
    min-height: 50px;
}

/* === SEO Content === */
.seo-content {
    padding: 32px 16px;
    border-top: 1px solid var(--border);
    margin-top: 24px;
}

.seo-content h2 {
    font-size: 1.2rem;
    color: var(--text);
    margin: 24px 0 8px;
}

.seo-content h2:first-child {
    margin-top: 0;
}

.seo-content p,
.seo-content li {
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.7;
}

.seo-content ul {
    padding-left: 20px;
    margin-top: 8px;
}

.seo-content li {
    margin-bottom: 6px;
}

/* === Footer === */
footer {
    border-top: 1px solid var(--border);
    padding: 20px 0;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 16px;
}

/* === Toast Notification === */
.toast {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 20px;
    font-size: 0.85rem;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.3s, transform 0.3s;
    z-index: 1000;
    pointer-events: none;
}

.toast.visible {
    opacity: 1;
    transform: translateY(0);
}

/* === Responsive === */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.3rem;
    }

    .editor-row {
        flex-direction: column;
    }

    .code-input,
    .code-output,
    .tree-output {
        min-height: 200px;
    }

    .toolbar {
        gap: 6px;
    }

    .btn-primary,
    .btn-secondary {
        padding: 6px 12px;
        font-size: 0.8rem;
    }

    .tabs {
        gap: 0;
    }

    .tab {
        padding: 8px 14px;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.1rem;
    }

    .container {
        padding: 0 10px;
    }
}