/* ============================================================
   SolveIterativeFunctions — Unified Stylesheet
   Based on complex-analysis.com format
   ============================================================ */

/* ----- CSS Custom Properties (Light Theme) ----- */
:root {
    --bg-color: #fafafa;
    --text-color: #333;
    --box-bg: #fff;
    --border-color: #ddd;
    --link-color: #1a73e8;
    --theorem-bg: #f0f7ff;
    --theorem-border: #1a73e8;
    --practice-bg: #f5f0ff;
    --practice-border: #7c4dff;
    --fixed-bar-bg: #2c3e50;
    --fixed-bar-text: #fff;
    --toc-bg: #f9f9f9;
    --footer-text: #777;
    --max-width: 800px;
    --card-bg: #fff;
    --card-shadow: 0 2px 8px rgba(0,0,0,0.08);
    --code-bg: #f4f4f4;
    --input-bg: #fff;
    --input-border: #ccc;
}

/* ----- Dark Theme ----- */
html.dark {
    --bg-color: #1a1a2e;
    --text-color: #e0e0e0;
    --box-bg: #16213e;
    --border-color: #444;
    --link-color: #64b5f6;
    --theorem-bg: #1a2740;
    --theorem-border: #64b5f6;
    --practice-bg: #261a40;
    --practice-border: #b388ff;
    --fixed-bar-bg: #0f0f23;
    --fixed-bar-text: #e0e0e0;
    --toc-bg: #1e2a3a;
    --footer-text: #888;
    --card-bg: #16213e;
    --card-shadow: 0 2px 8px rgba(0,0,0,0.3);
    --code-bg: #2a2a3e;
    --input-bg: #2a2a3e;
    --input-border: #555;
}

/* ----- Base Reset ----- */
*, *::before, *::after { box-sizing: border-box; }

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--bg-color);
    margin: 0;
    padding: 0 0 3rem 0;
    transition: background-color 0.3s, color 0.3s;
}

/* ----- Loader ----- */
.myLoader {
    position: fixed; top:0; left:0; width:100%; height:100%;
    background: var(--bg-color); z-index:9999; display:flex;
    flex-direction:column; align-items:center; justify-content:center;
    transition: opacity 0.3s;
}
.myLoader .dots { display:flex; gap:0.5rem; margin-bottom:1rem; }
.myLoader .dot {
    width:12px; height:12px; border-radius:50%; background: var(--fixed-bar-bg);
    animation: bounce 1.4s infinite ease-in-out both;
}
.myLoader .dot:nth-child(1) { animation-delay: -0.32s; }
.myLoader .dot:nth-child(2) { animation-delay: -0.16s; }
.myLoader .dot:nth-child(3) { animation-delay: 0s; }
@keyframes bounce {
    0%,80%,100% { transform: scale(0); }
    40% { transform: scale(1); }
}
.myLoader .loadingMessage { color: var(--footer-text); font-size:0.95rem; }

/* ----- Fixed Navigation Bar ----- */
.fixed-bar {
    position: fixed; top:0; left:0; width:100%;
    background: var(--fixed-bar-bg); color: var(--fixed-bar-text);
    display:flex; align-items:center; justify-content:space-between;
    padding: 0.5rem 1rem; z-index:100;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    font-size: 0.95rem;
}
.fixed-bar a, .fixed-bar span {
    color: var(--fixed-bar-text); text-decoration: none;
    cursor:pointer; margin:0 0.5rem;
}
.fixed-bar .link-container { display:flex; align-items:center; gap:0.5rem; }
.fixed-bar .center-link-group { display:flex; align-items:center; text-align:center; }
.fixed-bar .center-link-group .hover-prev,
.fixed-bar .center-link-group .hover-next { display:none; font-size:0.8rem; opacity:0.7; }
.fixed-bar .center-link-group:hover .hover-prev,
.fixed-bar .center-link-group:hover .hover-next { display:inline; }
.fixed-bar .center-link-group:hover .title-main { display:none; }
.fixed-bar .dark-mode-button {
    font-size:1.1rem; cursor:pointer; padding:0.2rem 0.4rem;
    border-radius:4px; transition: background 0.2s;
}
.fixed-bar .dark-mode-button:hover { background: rgba(255,255,255,0.15); }

/* ----- Main Container ----- */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1rem 1.5rem;
    background: var(--box-bg);
    box-shadow: 0 0 10px rgba(0,0,0,0.05);
    min-height: 80vh;
}

/* ----- TOC Chapter ----- */
.toc-chapter {
    background: var(--toc-bg);
    padding: 1rem 1.5rem;
    margin: 2rem 0 1rem 0;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}
.toc-chapter p { margin-top:0; font-weight:bold; }
.toc-chapter ul { list-style: none; padding-left:0; }
.toc-chapter ul li { margin:0.4rem 0; }
.toc-chapter ul li a {
    text-decoration: none; color: var(--link-color);
    transition: color 0.2s;
}
.toc-chapter ul li a:hover { text-decoration: underline; }

/* ----- Theorem & Practice Boxes ----- */
.theorem {
    background: var(--theorem-bg);
    border-left: 4px solid var(--theorem-border);
    padding: 1rem 1.25rem;
    margin: 1.5rem 0;
    border-radius: 0 4px 4px 0;
}
.practice {
    background: var(--practice-bg);
    border-left: 4px solid var(--practice-border);
    padding: 1rem 1.25rem;
    margin: 1.5rem 0;
    border-radius: 0 4px 4px 0;
}

/* ----- Definition Box ----- */
.definition {
    background: #f0fff4;
    border-left: 4px solid #38a169;
    padding: 1rem 1.25rem;
    margin: 1.5rem 0;
    border-radius: 0 4px 4px 0;
}
html.dark .definition {
    background: #1a3020;
    border-left-color: #68d391;
}

/* ----- Collapsible Details ----- */
details {
    margin: 1rem 0;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}
details summary {
    padding: 0.6rem 1rem;
    cursor: pointer;
    font-weight: 600;
    background: var(--toc-bg);
    user-select: none;
}
details summary:hover { background: var(--border-color); }
details .details-content { padding: 0.5rem 1rem 1rem; }

/* ----- Navigation Links (next/prev page) ----- */
.nextPage {
    text-align: right;
    font-weight: bold;
    margin-top: 2rem;
}
.nextPage a {
    text-decoration: none;
    color: var(--link-color);
}
.prevPage {
    text-align: left;
    font-weight: bold;
    margin-top: 0.5rem;
}

/* ----- Hero Section (index.html) ----- */
.hero {
    text-align: center;
    padding: 3rem 1rem 2rem;
}
.hero h1 { font-size: 2.5rem; color: var(--text-color); margin-bottom: 0.5rem; }
.hero p { font-size: 1.1rem; color: var(--footer-text); max-width: 600px; margin: 0 auto; }

/* ----- Card Grid (index.html) ----- */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}
.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    text-decoration: none;
    color: var(--text-color);
    transition: transform 0.2s, box-shadow 0.2s;
    box-shadow: var(--card-shadow);
}
.card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}
.card h3 { margin: 0 0 0.5rem; font-size: 1.2rem; }
.card h3 i { color: var(--link-color); margin-right: 0.5rem; }
.card p { margin: 0; font-size: 0.9rem; color: var(--footer-text); line-height: 1.5; }
.card .card-badge {
    display: inline-block;
    background: var(--theorem-bg);
    color: var(--theorem-border);
    padding: 0.2rem 0.6rem;
    border-radius: 12px;
    font-size: 0.75rem;
    margin-top: 0.8rem;
    font-weight: 600;
}

/* ----- Typography ----- */
h1 { font-size: 2rem; margin: 1.5rem 0 0.5rem; }
h2 { font-size: 1.5rem; margin: 2rem 0 0.5rem; color: var(--text-color); }
h3 { font-size: 1.2rem; margin: 1.5rem 0 0.5rem; }
p { margin: 0.8rem 0; }
a { color: var(--link-color); }
hr {
    border: none; border-top: 1px solid var(--border-color);
    margin: 2rem 0;
}
code {
    background: var(--code-bg);
    padding: 0.15rem 0.4rem;
    border-radius: 3px;
    font-size: 0.9em;
}
pre {
    background: var(--code-bg);
    padding: 1rem;
    border-radius: 4px;
    overflow-x: auto;
    font-size: 0.9em;
    line-height: 1.5;
}
blockquote {
    border-left: 3px solid var(--border-color);
    margin: 1rem 0;
    padding: 0.5rem 1rem;
    color: var(--footer-text);
}

/* ----- Tables ----- */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
}
th, td {
    padding: 0.5rem 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}
th { font-weight: 600; background: var(--toc-bg); }

/* ----- Forms & Inputs ----- */
input[type="text"],
input[type="number"],
input[type="range"],
select {
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--input-border);
    border-radius: 4px;
    font-size: 0.95rem;
    background: var(--input-bg);
    color: var(--text-color);
    transition: border-color 0.2s;
}
input:focus, select:focus {
    outline: none;
    border-color: var(--link-color);
    box-shadow: 0 0 0 2px rgba(26,115,232,0.2);
}
button, .btn {
    display: inline-block;
    padding: 0.5rem 1.25rem;
    border: none;
    border-radius: 4px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    background: var(--link-color);
    color: #fff;
    transition: background 0.2s, transform 0.1s;
}
button:hover, .btn:hover { opacity: 0.9; }
button:active, .btn:active { transform: scale(0.98); }
button.secondary {
    background: var(--toc-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

/* ----- Canvas / Chart containers ----- */
.canvas-container {
    border: 1px solid var(--border-color);
    margin: 1.5rem 0;
    text-align: center;
    background: var(--box-bg);
    border-radius: 4px;
    overflow: hidden;
}
canvas { display: block; margin: 0 auto; background: var(--box-bg); }

/* ----- Animated figures (manim videos) ----- */
.anim-figure {
    margin: 1.75rem 0;
    text-align: center;
}
.anim-figure video {
    display: block;
    width: 100%;
    max-width: 660px;
    margin: 0 auto;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: #0e1726;
    box-shadow: 0 2px 10px rgba(0,0,0,0.12);
}
.anim-figure figcaption {
    margin: 0.65rem auto 0;
    font-size: 0.9rem;
    color: var(--footer-text);
    max-width: 620px;
    line-height: 1.5;
}
.anim-figure figcaption .fig-label {
    font-weight: 600;
    color: var(--text-color);
}

/* ----- Multiplier classification table ----- */
.class-table { font-size: 0.95rem; }
.class-table code { white-space: nowrap; }

/* ----- Inline math-step callout ----- */
.keypoint {
    border-left: 4px solid var(--theorem-border);
    background: var(--toc-bg);
    padding: 0.75rem 1.1rem;
    margin: 1.25rem 0;
    border-radius: 0 4px 4px 0;
    font-size: 0.97rem;
}

/* ----- Control Panel ----- */
.control-panel {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    align-items: center;
    margin: 1rem;
}
.control-panel label { font-weight: 600; font-size: 0.9rem; }
.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
    align-items: flex-start;
}

/* ----- Results Display ----- */
.results-panel {
    background: var(--toc-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 1rem;
    margin: 1rem 0;
}
.results-panel .result-label { font-weight: 600; margin-bottom: 0.3rem; }
.results-panel .result-value { font-family: 'Courier New', monospace; word-break: break-all; }

/* ----- Comment Section ----- */
.comments-section {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}
.comments-section h3 { margin-bottom: 1rem; }

/* ----- Footer ----- */
footer {
    text-align: center;
    margin-top: 3rem;
    color: var(--footer-text);
    font-size: 0.95rem;
    line-height: 1.8;
}
footer a { color: var(--link-color); text-decoration: none; }
footer a:hover { text-decoration: underline; }
footer .footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
    margin-bottom: 0.5rem;
}

/* ----- Blog Post List ----- */
.blog-list { list-style: none; padding: 0; }
.blog-list li {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex; justify-content: space-between; align-items: flex-start;
    gap: 1rem;
}
.blog-list li .post-date {
    color: var(--footer-text);
    font-size: 0.85rem;
    white-space: nowrap;
}
.blog-entry {
    flex: 1;
    min-width: 0;
}
.blog-entry a {
    color: var(--text-color);
    text-decoration: none;
}
.blog-entry a:hover { color: var(--link-color); }
.blog-abstract {
    color: var(--footer-text);
    font-size: 0.92rem;
    line-height: 1.55;
    margin-top: 0.35rem;
}

/* ----- Solver / Article Utility Blocks ----- */
.hidden { display: none !important; }
.table-wrap {
    overflow-x: auto;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--box-bg);
}
.formula-block {
    overflow-x: auto;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--box-bg);
    padding: 0.75rem 0.9rem;
    margin: 0.5rem 0;
}
.notice-box {
    border-left: 4px solid var(--link-color);
    background: var(--box-bg);
    padding: 0.8rem 1rem;
    border-radius: 0 4px 4px 0;
    color: var(--text-color);
}
.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 0.9rem;
}
.control-panel-wrap {
    justify-content: flex-start;
    margin-left: 0;
    margin-right: 0;
}
.preset-strip {
    margin: 0.7rem 0 0.4rem;
    color: var(--footer-text);
    font-size: 0.92rem;
}
.preset-strip a {
    margin-left: 0.45rem;
    text-decoration: none;
}
.preset-strip a:hover { text-decoration: underline; }
.mode-switcher {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin: 1rem 0;
}
.mode-button {
    background: var(--toc-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
}
.mode-button.active {
    background: var(--link-color);
    color: #fff;
    border-color: var(--link-color);
}
.method-callout {
    border: 1px solid var(--border-color);
    background: var(--toc-bg);
    border-radius: 6px;
    padding: 0.85rem 1rem;
}
.graph-legend {
    text-align: center;
    font-size: 0.85rem;
    color: var(--footer-text);
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}
.chip-button {
    background: var(--box-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 999px;
    padding: 0.35rem 0.75rem;
    margin: 0.25rem 0.35rem 0.25rem 0;
    font-size: 0.86rem;
}
.media-card {
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: var(--toc-bg);
    padding: 0.9rem 1rem;
    margin: 1rem 0;
}
.media-card video,
.media-card img {
    width: 100%;
    height: auto;
    border-radius: 4px;
    margin-top: 0.75rem;
}
.diagram-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1rem;
    margin: 1rem 0;
}
.mini-diagram {
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: var(--box-bg);
    padding: 0.75rem;
}
.mini-diagram svg {
    width: 100%;
    height: auto;
    display: block;
}

/* ----- Utility ----- */
.text-center { text-align: center; }
.text-sm { font-size: 0.85rem; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

/* ============================================================
   Interactive Solver (KaTeX, live controls, cobweb grapher)
   ============================================================ */

/* KaTeX: keep display math from ballooning; inherit theme colour */
.katex { font-size: 1.05em; color: var(--text-color); }
.katex-display { margin: 0.4rem 0; overflow-x: auto; overflow-y: hidden; padding: 2px 0; }
.formula-block .katex-display { margin: 0; }

/* Live target preview */
.live-formula {
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: var(--box-bg);
    padding: 0.6rem 0.9rem;
    margin: 0.75rem 0;
    min-height: 2.4rem;
    overflow-x: auto;
}

/* Coefficient grid with synced sliders */
.coef-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(98px, 1fr));
    gap: 0.6rem 0.8rem;
    margin: 0.75rem 0;
}
.coef-cell {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.5rem 0.55rem;
    background: var(--toc-bg);
}
.coef-cell label { font-weight: 600; font-size: 0.85rem; text-align: center; }
.coef-cell input[type='number'] { width: 100%; text-align: center; }
.coef-cell input[type='range'] { width: 100%; margin: 0; accent-color: var(--link-color); cursor: pointer; }

/* Reactivity toggle row */
.solver-toolbar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.75rem 1.25rem;
    margin: 0.75rem 0;
}
.live-toggle { display: inline-flex; align-items: center; gap: 0.45rem; font-size: 0.9rem; cursor: pointer; }
.live-toggle input { width: auto; }

/* Status / classification pills */
.pill {
    display: inline-block;
    padding: 0.18rem 0.6rem;
    border-radius: 999px;
    font-size: 0.8rem;
    font-weight: 600;
    border: 1px solid transparent;
}
.pill-ok { background: #e6f7ec; color: #1b7f43; border-color: #9fdcb6; }
.pill-warn { background: #fff4e0; color: #9a6400; border-color: #f0cd8a; }
.pill-err { background: #fdecea; color: #b3261e; border-color: #f2b3ad; }
.pill-info { background: var(--toc-bg); color: var(--text-color); border-color: var(--border-color); }
html.dark .pill-ok { background: #133024; color: #7fe0a6; border-color: #2f6b48; }
html.dark .pill-warn { background: #33260f; color: #ffce7a; border-color: #6b5224; }
html.dark .pill-err { background: #36140f; color: #ff9a90; border-color: #6b2f28; }

/* Composita triangle */
.triangle-wrap { overflow-x: auto; margin: 0.5rem 0; }
table.triangle { border-collapse: collapse; margin: 0 auto; font-size: 0.8rem; }
table.triangle td {
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.5rem;
    text-align: center;
    font-family: 'Courier New', monospace;
    white-space: nowrap;
}
table.triangle td.tri-head { background: var(--toc-bg); font-weight: 600; font-family: inherit; }
table.triangle td.tri-empty { border: none; background: transparent; }
table.triangle td.tri-diag { background: var(--theorem-bg); }

/* Interactive grapher */
.grapher-shell { position: relative; }
.grapher-shell canvas { width: 100%; height: auto; display: block; cursor: crosshair; touch-action: none; }
.grapher-readout {
    position: absolute;
    top: 8px;
    left: 8px;
    background: var(--box-bg);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    padding: 0.3rem 0.55rem;
    font-size: 0.78rem;
    font-family: 'Courier New', monospace;
    pointer-events: none;
    opacity: 0.95;
    line-height: 1.5;
    white-space: nowrap;
}
.grapher-toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    justify-content: center;
    margin: 0.6rem 0;
}
.grapher-toolbar button { padding: 0.4rem 0.85rem; font-size: 0.88rem; }
.grapher-hint { text-align: center; font-size: 0.82rem; color: var(--footer-text); margin: 0.3rem 0 0; }

/* Reference list */
.ref-list { list-style: none; padding-left: 0; font-size: 0.92rem; }
.ref-list li { padding: 0.35rem 0; border-bottom: 1px dashed var(--border-color); }
.ref-list li:last-child { border-bottom: none; }
.ref-list .ref-tag {
    display: inline-block;
    min-width: 1.6rem;
    font-weight: 700;
    color: var(--link-color);
}

@media (max-width: 600px) {
    .coef-grid { grid-template-columns: repeat(3, 1fr); }
    .grapher-readout { font-size: 0.7rem; }
    table.triangle { font-size: 0.72rem; }
}

/* ----- Responsive ----- */
@media (max-width: 600px) {
    .container { padding: 0.5rem 0.75rem; }
    .hero h1 { font-size: 1.8rem; }
    .card-grid { grid-template-columns: 1fr; }
    .fixed-bar { padding: 0.4rem 0.5rem; font-size: 0.8rem; }
    .fixed-bar .hover-prev,
    .fixed-bar .hover-next { display: none !important; }
    .fixed-bar .center-link-group:hover .title-main { display: inline; }
    table { font-size: 0.85rem; }
    th, td { padding: 0.3rem 0.5rem; }
    .blog-list li {
        flex-direction: column;
        align-items: flex-start;
    }
    .blog-list li .post-date { white-space: normal; }
    .mode-switcher { flex-direction: column; }
    .mode-button { width: 100%; }
    .formula-block { padding: 0.65rem 0.75rem; }
}

@media print {
    .fixed-bar, .myLoader, .comments-section { display: none; }
    body { background: #fff; color: #000; }
    .container { box-shadow: none; max-width: 100%; }
}