/*
 * pca.css — page styles for the PCA demo.
 *
 * Mirrors the .gd-* / .km-* patterns from gradient-descent.css and
 * k-means.css.  Local prefix is .pca-*.
 */

/* ── Two 3D panels side by side ─────────────────────────────── */
.pca-demo {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.85rem;
    align-items: stretch;
}
@media (max-width: 900px) {
    .pca-demo { grid-template-columns: 1fr; }
}

.pca-canvas-wrap {
    position: relative;
    background: var(--ms-panel-bg);
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius);
    overflow: hidden;
    box-shadow: var(--ms-shadow-sm);
}
.pca-3d {
    width: 100%;
    height: 100%;
    min-height: 360px;
}
.pca-3d .modebar {
    background: transparent !important;
    opacity: 0.4;
    transition: opacity var(--ms-transition);
}
.pca-canvas-wrap:hover .modebar { opacity: 1; }
.pca-canvas-label {
    position: absolute; top: 0.65rem; left: 0.85rem;
    font: 500 0.72rem var(--ms-font-mono);
    color: var(--ms-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    background: var(--ms-panel-bg);
    padding: 0.2rem 0.5rem;
    border-radius: var(--ms-radius-sm);
    border: 1px solid var(--ms-line);
    z-index: 5;
}
.pca-canvas-readout {
    position: absolute; bottom: 0.65rem; left: 0.85rem; right: 0.85rem;
    display: flex; justify-content: space-between; gap: 0.5rem;
    font: 500 0.74rem var(--ms-font-mono);
    color: var(--ms-ink-soft);
    pointer-events: none;
    z-index: 5;
}
.pca-canvas-readout span {
    background: rgba(254, 253, 251, 0.85);
    padding: 0.18rem 0.5rem;
    border-radius: var(--ms-radius-sm);
    backdrop-filter: blur(4px);
}
[data-theme="dark"] .pca-canvas-readout span {
    background: rgba(28, 25, 23, 0.75);
}

/* ── Scree plot (full-width below the 3D panels) ────────────── */
.pca-scree-wrap {
    position: relative;
    background: var(--ms-panel-bg);
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius);
    padding: 1rem 1.1rem;
    margin-top: 0.85rem;
    box-shadow: var(--ms-shadow-sm);
}
.pca-scree-label {
    font: 500 0.72rem var(--ms-font-mono);
    color: var(--ms-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 0.45rem;
}
.pca-scree-canvas {
    display: block;
    width: 100%;
    height: 120px;
}

/* ── Controls (mirrors .gd-controls) ────────────────────────── */
.pca-controls {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 0.85rem;
    padding: 1rem 1.1rem;
    background: var(--ms-panel-bg);
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius);
    margin-top: 0.85rem;
}
.pca-control {
    display: flex; flex-direction: column; gap: 0.35rem;
}
.pca-control-wide {
    grid-column: 1 / -1;
}
.pca-dataset-story {
    font: 0.78rem/1.4 var(--ms-font-sans);
    color: var(--ms-muted);
    font-style: italic;
    margin-top: 0.1rem;
}
.pca-control-label {
    display: flex; justify-content: space-between; align-items: baseline;
    font: 500 0.78rem var(--ms-font-sans);
    color: var(--ms-ink-soft);
}
.pca-control-value {
    font: 500 0.76rem var(--ms-font-mono);
    color: var(--ms-accent);
}
.pca-control input[type="range"] {
    width: 100%;
    appearance: none;
    height: 4px;
    background: var(--ms-accent-soft);
    border-radius: var(--ms-radius-pill);
    cursor: pointer;
}
.pca-control input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 16px; height: 16px;
    background: var(--ms-accent);
    border-radius: 50%;
    cursor: pointer;
}
.pca-control input[type="range"]::-moz-range-thumb {
    width: 16px; height: 16px;
    background: var(--ms-accent);
    border-radius: 50%;
    border: none;
}
.pca-control select,
.pca-control input[type="number"] {
    padding: 0.45rem 0.6rem;
    font: 500 0.85rem var(--ms-font-sans);
    color: var(--ms-ink);
    background: var(--ms-panel-bg-soft);
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius-sm);
    outline: none;
}
.pca-control select:focus,
.pca-control input[type="number"]:focus {
    border-color: var(--ms-accent);
    box-shadow: var(--ms-ring);
}
.pca-control-checkbox {
    display: flex; align-items: center; gap: 0.4rem;
    font: 500 0.85rem var(--ms-font-sans);
    color: var(--ms-ink-soft);
    cursor: pointer;
}
.pca-control-checkbox input { accent-color: var(--ms-accent); width: 16px; height: 16px; }

/* ── Actions row ────────────────────────────────────────────── */
.pca-actions {
    display: flex; gap: 0.6rem; flex-wrap: wrap;
    margin-top: 0.85rem;
}
.pca-btn {
    display: inline-flex; align-items: center; gap: 0.45rem;
    padding: 0.55rem 1.1rem;
    font: 500 0.86rem var(--ms-font-sans);
    border-radius: var(--ms-radius-sm);
    border: 1px solid var(--ms-line);
    background: var(--ms-panel-bg);
    color: var(--ms-ink);
    cursor: pointer;
    transition: transform var(--ms-transition), box-shadow var(--ms-transition);
}
.pca-btn:hover { transform: translateY(-1px); box-shadow: var(--ms-shadow-sm); }
.pca-btn[disabled] { opacity: 0.5; cursor: not-allowed; transform: none; }
.pca-btn.is-primary {
    background: linear-gradient(135deg, var(--ms-cta-start), var(--ms-cta-end));
    color: #fff;
    border-color: transparent;
    box-shadow: 0 1px 3px var(--ms-cta-shadow);
}
.pca-btn.is-primary:hover { box-shadow: 0 4px 12px var(--ms-cta-shadow); }
.pca-btn.is-busy { pointer-events: none; position: relative; }
.pca-btn.is-busy::after {
    content: '';
    width: 12px; height: 12px;
    border: 2px solid currentColor;
    border-top-color: transparent;
    border-radius: 50%;
    animation: pca-spin 0.7s linear infinite;
}
@keyframes pca-spin { to { transform: rotate(360deg); } }

/* ── Code panel ─────────────────────────────────────────────── */
.pca-code {
    background: var(--ms-panel-bg);
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius);
    overflow: hidden;
}
.pca-code-header {
    display: flex; justify-content: space-between; align-items: center;
    padding: 0.55rem 1rem;
    background: var(--ms-panel-bg-soft);
    border-bottom: 1px solid var(--ms-line);
    font: 500 0.78rem var(--ms-font-mono);
    color: var(--ms-muted);
}
.pca-code-header .pca-code-title {
    display: inline-flex; align-items: center; gap: 0.45rem;
}
.pca-code-header .pca-code-title::before {
    content: '';
    width: 8px; height: 8px;
    border-radius: 50%;
    background: var(--ms-accent);
    box-shadow: 0 0 0 3px var(--ms-accent-soft);
}
.pca-code-actions { display: flex; gap: 0.4rem; }
.pca-code-actions button {
    font: 500 0.74rem var(--ms-font-mono);
    color: var(--ms-muted);
    background: transparent;
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius-sm);
    padding: 0.25rem 0.6rem;
    cursor: pointer;
}
.pca-code-actions button:hover { color: var(--ms-accent); border-color: var(--ms-accent); }
.pca-code textarea {
    display: block;
    width: 100%;
    min-height: 360px;
    padding: 1rem 1.1rem;
    font: 400 0.86rem/1.55 var(--ms-font-mono);
    color: var(--ms-ink);
    background: var(--ms-panel-bg);
    border: 0;
    outline: 0;
    resize: vertical;
    tab-size: 4;
}

/* ── Console ────────────────────────────────────────────────── */
.pca-console {
    margin-top: 0.85rem;
    background: #0c0a09;
    color: #e7e5e4;
    border-radius: var(--ms-radius-sm);
    padding: 0.75rem 1rem;
    font: 400 0.78rem/1.55 var(--ms-font-mono);
    max-height: 200px;
    overflow: auto;
    border: 1px solid var(--ms-line);
}
.pca-console:empty { display: none; }
.pca-console .pca-err { color: #fca5a5; }

/* ── Math derivation card (5 steps) ─────────────────────────── */
.pca-math {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.75rem;
}
.pca-math-step {
    padding: 0.85rem 1rem;
    background: var(--ms-panel-bg-soft);
    border-left: 3px solid var(--ms-accent);
    border-radius: var(--ms-radius-sm);
}
.pca-math-step h4 {
    font: 500 0.85rem var(--ms-font-sans);
    color: var(--ms-ink);
    margin: 0 0 0.45rem;
}
.pca-math-step p {
    font: 0.86rem/1.55 var(--ms-font-sans);
    color: var(--ms-ink-soft);
    margin: 0;
}
.pca-math-step .katex-display { margin: 0.5rem 0 0 !important; }

/* ── Try this exercises ─────────────────────────────────────── */
.pca-try {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 0.75rem;
}
.pca-try-item {
    padding: 0.85rem 1rem;
    background: var(--ms-panel-bg-soft);
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius-sm);
}
.pca-try-item h4 {
    font: 500 0.88rem var(--ms-font-sans);
    color: var(--ms-ink);
    margin: 0 0 0.3rem;
}
.pca-try-item p {
    font: 0.82rem/1.5 var(--ms-font-sans);
    color: var(--ms-muted);
    margin: 0;
}
.pca-try-item code {
    font: 0.78rem var(--ms-font-mono);
    color: var(--ms-accent);
    background: var(--ms-accent-soft);
    padding: 0.05rem 0.3rem;
    border-radius: 3px;
}

/* ── Chip strips for watch-out / in-practice ─────────────────── */
.pca-strip {
    display: flex; flex-wrap: wrap; gap: 0.4rem;
    align-items: center;
    padding: 0.55rem 0.85rem;
    margin: 0.65rem 0;
    border-radius: var(--ms-radius-sm);
    background: var(--ms-panel-bg-soft);
    border-left: 3px solid var(--ms-line);
}
.pca-strip-label {
    display: inline-flex; align-items: center; gap: 0.3rem;
    font: 500 0.7rem var(--ms-font-mono);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--ms-muted);
    margin-right: 0.4rem;
    flex-shrink: 0;
}
.pca-strip.is-watchout {
    background: rgba(245, 158, 11, 0.05);
    border-left-color: #f59e0b;
}
.pca-strip.is-watchout .pca-strip-label { color: #b45309; }
[data-theme="dark"] .pca-strip.is-watchout .pca-strip-label { color: #fbbf24; }
.pca-strip.is-practice {
    background: rgba(34, 197, 94, 0.04);
    border-left-color: #15803d;
}
.pca-strip.is-practice .pca-strip-label { color: #15803d; }
[data-theme="dark"] .pca-strip.is-practice .pca-strip-label { color: #86efac; }
.pca-tag {
    display: inline-flex; align-items: center;
    padding: 0.2rem 0.6rem;
    background: var(--ms-panel-bg);
    border: 1px solid var(--ms-line);
    border-radius: var(--ms-radius-pill);
    font: 500 0.76rem var(--ms-font-sans);
    color: var(--ms-ink-soft);
    white-space: nowrap;
}
.pca-strip.is-practice .pca-tag {
    font-family: var(--ms-font-mono);
    font-size: 0.74rem;
    color: var(--ms-accent);
    background: var(--ms-accent-softer);
    border-color: var(--ms-accent-soft);
}