/* ============================================================
   CSS Book — Interactive & Reference Styles
   Playground (live editor), diagrams, value tables, intro, TOC.
   Uses the shared theme variables from theme-light/theme-dark.css.
   ============================================================ */

/* ---------- Module intro ---------- */
.module-intro {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 14px;
    padding: 28px 30px;
    margin-bottom: 32px;
}
.module-intro h1 {
    margin: 0 0 12px;
    font-size: 1.9rem;
    color: var(--text-primary);
}
.module-intro p {
    color: var(--text-secondary);
    max-width: 70ch;
    line-height: 1.7;
    margin: 0 0 18px;
}
.intro-stats { display: flex; gap: 14px; flex-wrap: wrap; }
.intro-stats .stat {
    background: var(--accent-light);
    color: var(--accent);
    border: 1px solid var(--accent-border);
    border-radius: 10px;
    padding: 8px 16px;
    font-size: 0.95rem;
}
.intro-stats .stat strong { font-size: 1.2rem; }

/* ---------- Chapter / property meta ---------- */
.category-header { display: flex; align-items: center; gap: 10px; }
.chapter-badge {
    display: inline-flex; align-items: center; justify-content: center;
    width: 34px; height: 34px; border-radius: 50%;
    background: var(--accent); color: #fff;
    font-size: 1rem; font-weight: 700; flex: none;
}
.chapter-num { color: var(--text-muted); font-weight: 600; margin-right: 2px; }
.prop-subtitle {
    margin: -4px 0 12px; color: var(--text-secondary);
    font-size: 0.98rem; font-weight: 600;
}

/* ---------- Syntax & values ---------- */
.syntax-section, .values-section, .diagram-section, .examples-section, .real-world {
    margin-top: 18px;
}
.syntax-section h4, .values-section h4, .diagram-section h4,
.examples-section h4, .real-world h4 {
    font-size: 0.95rem; text-transform: uppercase; letter-spacing: .04em;
    color: var(--text-muted); margin: 0 0 10px;
}
.values-table {
    width: 100%; border-collapse: collapse; font-size: 0.95rem;
    border: 1px solid var(--border-color); border-radius: 8px; overflow: hidden;
}
.values-table th {
    text-align: left; background: var(--bg-tertiary); color: var(--text-secondary);
    padding: 10px 14px; font-weight: 600; border-bottom: 1px solid var(--border-color);
}
.values-table td {
    padding: 10px 14px; border-bottom: 1px solid var(--border-light);
    color: var(--text-secondary); vertical-align: top;
}
.values-table tr:last-child td { border-bottom: none; }
.values-table td:first-child { white-space: nowrap; }
.values-table code {
    background: var(--code-bg); color: var(--accent);
    padding: 2px 7px; border-radius: 5px; font-size: 0.9em;
}

/* ---------- Tip box ---------- */
.tip-box {
    margin-top: 16px; padding: 12px 16px;
    background: var(--accent-light); border-left: 4px solid var(--accent);
    border-radius: 8px; color: var(--text-secondary); line-height: 1.6;
}
.tip-box strong { color: var(--text-primary); }

/* ---------- Real world ---------- */
.real-world-body {
    background: var(--bg-secondary); border: 1px solid var(--border-color);
    border-radius: 8px; padding: 14px 16px; color: var(--text-secondary); line-height: 1.7;
}
.real-world-body code {
    background: var(--code-bg); padding: 2px 6px; border-radius: 4px; color: var(--code-keyword);
}

/* ============================================================
   PLAYGROUND — live code editor + preview
   ============================================================ */
.playground {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    background: var(--bg-secondary);
    margin-bottom: 16px;
}
.playground-editor { display: flex; flex-direction: column; gap: 10px; padding: 12px; }
.editor-pane {
    border: 1px solid var(--border-color); border-radius: 8px;
    overflow: hidden; background: var(--bg-code, var(--code-bg));
}
.editor-label {
    display: flex; align-items: center; justify-content: space-between;
    padding: 6px 10px; font-size: 0.78rem; font-weight: 700;
    text-transform: uppercase; letter-spacing: .05em;
    color: var(--text-muted); background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
}
.editor-pane[data-lang="html"] .editor-label { color: #e06c75; }
.editor-pane[data-lang="css"] .editor-label { color: var(--accent); }
.code-input {
    width: 100%; border: none; resize: vertical;
    background: var(--bg-code, var(--code-bg)); color: var(--code-text, var(--text-primary));
    font-family: 'Cascadia Code', 'Fira Code', Consolas, 'Courier New', monospace;
    font-size: 0.88rem; line-height: 1.6; padding: 12px;
    tab-size: 2; outline: none; min-height: 70px;
}
.code-input:focus { box-shadow: inset 0 0 0 2px var(--focus-ring, var(--accent)); }

.playground-preview {
    display: flex; flex-direction: column;
    border-left: 1px solid var(--border-color);
    background: var(--bg-primary);
}
.preview-label {
    display: flex; align-items: center; justify-content: space-between;
    padding: 8px 12px; font-size: 0.8rem; font-weight: 700;
    color: var(--text-secondary); background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
}
.preview-frame {
    width: 100%; flex: 1; min-height: 120px; border: none; background: #fff;
}
.btn-reset {
    background: transparent; border: 1px solid var(--border-color);
    color: var(--text-secondary); border-radius: 6px; cursor: pointer;
    padding: 3px 10px; font-size: 0.78rem;
}
.btn-reset:hover { background: var(--bg-tertiary); color: var(--text-primary); }

/* ============================================================
   BOX MODEL diagram
   ============================================================ */
.boxmodel-demo, .flex-demo, .grid-demo, .pos-demo {
    border: 1px solid var(--border-color); border-radius: 12px;
    padding: 16px; background: var(--bg-secondary);
}
.bm-controls, .flex-controls, .grid-controls, .pos-controls {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 12px; margin-bottom: 18px;
}
.bm-controls label, .grid-controls label, .pos-controls label,
.flex-controls label {
    display: flex; flex-direction: column; gap: 4px;
    font-size: 0.85rem; color: var(--text-secondary); font-weight: 600;
}
.bm-controls input[type=range], .grid-controls input[type=range], .pos-controls input[type=range] {
    width: 100%; accent-color: var(--accent);
}
.flex-controls select, .pos-controls select {
    padding: 6px 8px; border: 1px solid var(--border-color); border-radius: 6px;
    background: var(--bg-primary); color: var(--text-primary);
}
.bm-stage { display: flex; justify-content: center; padding: 10px; }
.bm-margin   { background: rgba(247, 202, 24, .35); position: relative; }
.bm-border   { background: rgba(40, 167, 69, .35); border: solid rgba(40,167,69,.7); position: relative; }
.bm-padding  { background: rgba(0, 123, 255, .30); position: relative; }
.bm-content  {
    background: var(--accent); color: #fff;
    display: flex; align-items: center; justify-content: center;
    font-weight: 700; min-width: 40px;
}
.bm-tag {
    position: absolute; top: 2px; left: 6px; font-size: 0.68rem;
    font-weight: 700; color: #444; text-transform: uppercase; letter-spacing: .04em;
}

/* ============================================================
   FLEXBOX diagram
   ============================================================ */
.flex-stage {
    min-height: 160px; border: 2px dashed var(--accent-border); border-radius: 8px;
    padding: 10px; gap: 8px; background: var(--bg-primary);
}
.flex-box {
    background: var(--accent); color: #fff; border-radius: 6px;
    min-width: 52px; min-height: 52px; display: flex;
    align-items: center; justify-content: center; font-weight: 700;
}
.flex-output, .grid-output {
    margin: 14px 0 0; background: var(--bg-code, var(--code-bg));
    color: var(--code-text, var(--text-primary)); border-radius: 8px;
    padding: 12px 14px; font-size: 0.85rem; white-space: pre-wrap;
    font-family: 'Cascadia Code', Consolas, monospace; overflow-x: auto;
}

/* ============================================================
   GRID diagram
   ============================================================ */
.grid-stage {
    min-height: 180px; border: 2px dashed var(--accent-border); border-radius: 8px;
    padding: 10px; background: var(--bg-primary);
}
.grid-cell {
    background: var(--accent); color: #fff; border-radius: 6px;
    display: flex; align-items: center; justify-content: center;
    font-weight: 700; min-height: 40px;
}

/* ============================================================
   POSITIONING diagram
   ============================================================ */
.pos-stage {
    position: relative; min-height: 220px; border: 2px dashed var(--accent-border);
    border-radius: 8px; padding: 10px; background: var(--bg-primary); overflow: hidden;
}
.pos-sibling {
    background: var(--bg-tertiary); color: var(--text-secondary);
    border: 1px solid var(--border-color); border-radius: 6px;
    padding: 12px; margin: 8px 0; text-align: center;
}
.pos-target {
    background: var(--accent); color: #fff; border-radius: 6px;
    padding: 12px 18px; text-align: center; font-weight: 700; width: 120px;
    box-shadow: var(--shadow-md);
}

/* ============================================================
   Quick-nav TOC (right sidebar)
   ============================================================ */
.toc-list { list-style: none; margin: 0; padding: 0; }
.toc-link {
    display: block; padding: 6px 10px; border-radius: 6px;
    color: var(--text-secondary); text-decoration: none;
    font-size: 0.88rem; border-left: 2px solid transparent;
}
.toc-link:hover { background: var(--bg-tertiary); color: var(--text-primary); }
.toc-link.active {
    color: var(--accent); border-left-color: var(--accent);
    background: var(--accent-light); font-weight: 600;
}

/* ---------- No results ---------- */
.no-results {
    text-align: center; padding: 60px 20px; color: var(--text-muted); font-size: 1.1rem;
}

/* ---------- Responsive: stack playground on small screens ---------- */
@media (max-width: 820px) {
    .playground { grid-template-columns: 1fr; }
    .playground-preview { border-left: none; border-top: 1px solid var(--border-color); }
}