/* Google Fonts: Lora for headings, Lato for body */
@import url('https://fonts.googleapis.com/css2?family=Lora:ital,wght@0,400;0,600;1,400&family=Lato:wght@400;700&display=swap');

:root {
    --font-heading: 'Lora', serif;
    --font-body: 'Lato', sans-serif;

    --color-text: #2d3748;
    --color-text-secondary: #718096;
    --color-accent: #2b6cb0;
    --color-accent-light: #ebf4ff;
    --color-accent-darker: #1a365d;
    --color-bg: #ffffff;
    --color-bg-light: #f7fafc;
    --color-border: #e2e8f0;

    --layout-max-width: 1000px;
    --border-radius-main: 6px;
}

/* Basic Reset and Setup */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.65;
    font-size: 17px;
    -webkit-font-smoothing: antialiased;
    zoom: 1.3;
}

.container {
    max-width: var(--layout-max-width);
    margin: 0 auto;
    padding: 70px 25px;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--color-border);
}

h1 {
    font-family: var(--font-heading);
    font-size: 1.9em;
    font-weight: 600;
    line-height: 1.25;
    margin-bottom: 20px;
}

/* ===== Related Links Dropdown (in top-controls) ===== */
.top-controls .related-links-wrapper {
    position: relative;
}
.top-controls .related-links-dropdown {
    display: none;
    position: absolute;
    right: 0;
    top: calc(100% + 8px);
    background: white;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-main);
    box-shadow: 0 8px 28px rgba(0,0,0,0.12);
    z-index: 1020;
    min-width: 400px;
    padding: 6px 0;
    animation: dropdownFadeIn 0.2s ease;
}
@keyframes dropdownFadeIn {
    from { opacity: 0; transform: translateY(-6px); }
    to { opacity: 1; transform: translateY(0); }
}
.top-controls .related-links-dropdown.open {
    display: block;
}
.top-controls .related-links-dropdown a {
    display: block;
    padding: 9px 18px;
    color: var(--color-text);
    text-decoration: none;
    font-size: 0.82em;
    white-space: nowrap;
    transition: background 0.2s ease, color 0.2s ease, padding-left 0.2s ease;
}
.top-controls .related-links-dropdown a:hover {
    background: linear-gradient(90deg, rgba(41,128,185,0.08) 0%, transparent 100%);
    color: var(--color-accent);
    padding-left: 22px;
}

/* ===== Authors Fellows Line ===== */
.authors-fellows {
    margin-bottom: 12px;
}

.authors {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 12px 15px;
    margin-bottom: 12px;
    font-size: 1.05em;
}

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

/* Global hyperlink styling */
.section-content a, .tutorial-text a {
    color: var(--color-accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: color 0.25s ease, border-color 0.25s ease;
}
.section-content a:hover, .tutorial-text a:hover {
    color: #1a5276;
    border-bottom-color: #1a5276;
}
.author sup {
    color: var(--color-accent);
    font-weight: bold;
}

.affiliations {
    font-size: 0.9em;
    color: var(--color-text-secondary);
    line-height: 1.0;
}
.affiliation {
    display: inline-block;
    margin: 4px 10px;
}

/* Redesigned venue block */
.venue {
    margin-top: 12px;
    color: var(--color-accent);
    font-weight: 700;
    font-style: italic;
    font-size: 0.95em;
}

/* Buttons */
.action-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 12px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 3px 9px;
    background-color: white;
    color: var(--color-accent);
    text-decoration: none;
    border-radius: var(--border-radius-main);
    font-weight: 700;
    font-size: 0.95em;
    transition: all 0.25s ease;
    border: 2px solid var(--color-accent);
}
.btn:hover {
    background-color: var(--color-accent);
    color: var(--color-bg);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.1);
}
.btn svg {
    width: 20px;
    height: 20px;
}
        
/* New Fixed Global Controls */
.top-controls {
    position: fixed;
    top: 20px;
    right: 25px;
    z-index: 1010;
    display: flex;
    gap: 10px;
}
.control-btn {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    color: var(--color-text-secondary);
    transition: all 0.2s ease;
    position: relative; /* Added for tooltip positioning */
}
.control-btn:hover {
    color: var(--color-accent);
    border-color: var(--color-accent);
    transform: translateY(-2px);
}
.control-btn svg {
    width: 20px;
    height: 20px;
}

/* Tooltip base style */
.tooltip {
    position: absolute;
    background: var(--color-accent-darker);
    color: white;
    padding: 5px 12px;
    border-radius: 6px;
    white-space: nowrap;
    font-size: 13px;
    font-weight: 500;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease, transform 0.3s ease;
}

/* Tooltip for side nav */
.side-nav .tooltip {
    right: 28px;
    top: 50%;
    transform: translateY(-50%) translateX(5px); /* Start slightly to the right */
}
.side-nav .nav-dot:hover .tooltip {
    opacity: 1;
    transform: translateY(-50%) translateX(0);
}

/* Tooltip for top controls */
.top-controls .tooltip {
    top: 110%; /* Position below the button */
    left: 50%;
    transform: translateX(-50%) translateY(-5px); /* Start slightly up */
}
.top-controls .control-btn:hover .tooltip {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}


/* Sections */
.section {
    margin-bottom: 30px;
    scroll-margin-top: 40px;
    padding: 28px 32px;
    background: var(--color-bg);
    border-radius: 8px;
    border: 1px solid var(--color-border);
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.section-title {
    font-family: var(--font-heading);
    font-size: 1.5em;
    font-weight: 600;
    margin-bottom: 20px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--color-accent);
    display: inline-block;
    color: var(--color-accent-darker);
}
.section-content {
    line-height: 1.5;
}
.section-content p {
    margin-bottom: 1em;
}

/* TL;DR Section */
.tldr {
    background: linear-gradient(135deg, var(--color-accent-light) 0%, #f0f7ff 100%);
    padding: 28px 32px;
    border-radius: 8px;
    margin-bottom: 35px;
    border-left: 4px solid var(--color-accent);
    border: 1px solid #bee3f8;
    text-align: justify;
    box-shadow: 0 2px 8px rgba(43,108,176,0.06);
}
.tldr-title {
    font-family: var(--font-heading);
    font-weight: 600;
    color: var(--color-accent-darker);
    margin-bottom: 12px;
    font-size: 1.25em;
    border-bottom: none;
    padding-bottom: 0;
    letter-spacing: 0.02em;
}
/* Align numbered list in TL;DR with heading text */
.tldr ol {
    padding-left: 1.2em;
    margin-left: 0;
}
/* Fix for TLDR bottom spacing */
.tldr .section-content p:last-child {
    margin-bottom: 0;
}
        
.tutorial-text {
    text-align: justify;
}
.placeholder-text {
    color: var(--color-text-secondary);
    font-style: italic;
}

/* Side Navigation */
.side-nav {
    position: fixed;
    right: 30px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.nav-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: transparent;
    border: 2px solid #bdc3c7;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}
.nav-dot:hover, .nav-dot.active {
    border-color: var(--color-accent);
    transform: scale(1.3);
}
.nav-dot.active {
    background-color: var(--color-accent);
}
        
/* Modal */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(44, 62, 80, 0.7);
    display: flex; justify-content: center; align-items: center;
    z-index: 2000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}
.modal-overlay.visible { opacity: 1; pointer-events: auto; }
.modal-content {
    background: var(--color-bg); padding: 30px;
    border-radius: var(--border-radius-main); width: 90%; max-width: 600px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    transform: scale(0.95); transition: transform 0.3s ease;
}
.modal-overlay.visible .modal-content { transform: scale(1); }
.modal-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; }
.modal-title { font-family: var(--font-heading); font-size: 1.4em; }
.modal-close { background: none; border: none; cursor: pointer; font-size: 2em; line-height: 1; color: var(--color-text-secondary); transition: color 0.2s ease; }
.modal-close:hover { color: var(--color-text); }
#bibtex-code {
    width: 100%; height: 250px; font-family: "Courier New", Consolas, monospace; font-size: 0.9em;
    background: var(--color-bg-light); border: 1px solid var(--color-border); text-align: justify;
    border-radius: var(--border-radius-main); padding: 15px; resize: none; color: var(--color-text);
    white-space: pre; tab-size: 4; line-height: 1.5;
}
.modal-actions { margin-top: 20px; text-align: right; }
#copy-bibtex-btn {
    padding: 10px 20px; border: none; background: var(--color-accent);
    color: white; font-weight: 700; border-radius: var(--border-radius-main);
    cursor: pointer; transition: background-color 0.2s ease; min-width: 150px;
}
#copy-bibtex-btn:hover { background-color: #3498db; }
        
/* Footer */
.footer { margin-top: 30px; padding-top: 30px; border-top: 1px solid var(--color-border); text-align: center; color: var(--color-text-secondary); font-size: 0.9em; }

/* Scroll Animation */
.fade-in-section {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.fade-in-section.is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 1100px) {
    .side-nav { display: none; }
}
@media (max-width: 768px) {
    body { font-size: 16px; }
    h1 { font-size: 2.2em; }
    .container { padding: 50px 20px; }
    .top-controls { top: 15px; right: 15px; }
    .action-buttons { flex-direction: column; align-items: center; }
    .btn { width: 220px; justify-content: center; }
}

/* Methodology figure */
.methodology-figure {
    margin: 15px 0;
    padding: 0;
    border: none;
    background: none;
}

.methodology-figure img {
    width: 100%;
    height: auto;
    display: block;
    margin: 0 auto;
}

.methodology-figure figcaption {
    margin-top: 10px;
    text-align: justify;
    font-size: 0.9em;
    color: var(--color-text-secondary);
    font-style: italic;
    line-height: 1.4;
}

/* ===== Subsection Titles ===== */
.subsection-title {
    font-family: var(--font-heading);
    font-size: 1.18em;
    font-weight: 600;
    margin: 28px 0 14px 0;
    color: var(--color-accent-darker);
    padding-bottom: 4px;
    border-bottom: 1px solid var(--color-border);
    display: inline-block;
}

/* ===== Collapsible Derivation Blocks ===== */
.collapsible {
    margin: 22px 0;
    border: 1px solid #d4e4f1;
    border-radius: 8px;
    overflow: hidden;
    background: #fafcfe;
}
.collapsible-toggle {
    width: 100%;
    padding: 13px 18px;
    background: linear-gradient(135deg, #edf2f7 0%, #f7fafc 100%);
    border: none;
    cursor: pointer;
    font-family: var(--font-body);
    font-size: 0.95em;
    font-weight: 700;
    color: var(--color-accent);
    text-align: left;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: background 0.25s ease, color 0.25s ease;
}
.collapsible-toggle::before {
    content: '\25B6';
    display: inline-block;
    font-size: 0.7em;
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    flex-shrink: 0;
}
.collapsible.open .collapsible-toggle::before {
    transform: rotate(90deg);
}
.collapsible-toggle:hover {
    background: #eef3f7;
}
.collapsible-content {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.5s cubic-bezier(0.33, 1, 0.68, 1);
}
.collapsible-content > div {
    overflow: hidden;
    padding: 0 18px;
    transition: padding 0.5s cubic-bezier(0.33, 1, 0.68, 1);
}
.collapsible.open .collapsible-content {
    grid-template-rows: 1fr;
}
.collapsible.open .collapsible-content > div {
    padding: 15px 18px;
}
.collapsible-content p {
    margin-bottom: 0.8em;
}

/* ===== Interactive Visualization Containers ===== */
.viz-container {
    margin: 28px 0;
    padding: 24px;
    background: linear-gradient(135deg, #f7fafc 0%, #edf2f7 100%);
    border-radius: 8px;
    border: 1px solid #d4e4f1;
    box-shadow: 0 2px 10px rgba(43,108,176,0.06);
}
.viz-canvas {
    width: 100%;
    height: 380px;
    background: #fdfdfe;
    border: 1px solid #d4e4f1;
    border-radius: 6px;
    display: block;
    cursor: crosshair;
    box-shadow: inset 0 1px 4px rgba(0, 0, 0, 0.03);
}
.viz-controls {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-top: 14px;
    flex-wrap: wrap;
    font-size: 0.95em;
    color: var(--color-text-secondary);
    font-weight: 500;
}
.viz-controls label {
    display: flex;
    align-items: center;
    gap: 6px;
}
.viz-controls input[type="range"] {
    width: 110px;
    accent-color: var(--color-accent);
    height: 4px;
}
.viz-controls select {
    padding: 5px 10px;
    border: 1px solid var(--color-border);
    border-radius: 5px;
    font-size: 0.88em;
    color: var(--color-text);
    background: white;
    transition: border-color 0.2s ease;
}
.viz-controls select:hover {
    border-color: var(--color-accent);
}
.viz-btn {
    padding: 5px 16px;
    border: 1px solid var(--color-accent);
    border-radius: 5px;
    background: white;
    color: var(--color-accent);
    font-weight: 700;
    font-size: 0.85em;
    cursor: pointer;
    transition: all 0.2s ease;
}
.viz-btn:hover {
    background: var(--color-accent);
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 2px 6px rgba(41, 128, 185, 0.25);
}
.viz-btn:active {
    transform: translateY(0);
    box-shadow: none;
}
.viz-caption {
    margin-top: 12px;
    font-size: 0.88em;
    color: var(--color-text-secondary);
    font-style: italic;
    line-height: 1.5;
    text-align: justify;
}

/* ===== Content Tables ===== */
.table-wrapper {
    overflow-x: auto;
    margin: 18px 0;
    border-radius: 8px;
    border: 1px solid var(--color-border);
}
.content-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.92em;
    line-height: 1.5;
}
.content-table th {
    background: linear-gradient(135deg, var(--color-accent-darker) 0%, var(--color-accent) 100%);
    color: white;
    padding: 11px 14px;
    text-align: left;
    font-weight: 700;
    font-size: 0.95em;
}
.content-table td {
    padding: 10px 14px;
    border-bottom: 1px solid var(--color-border);
    vertical-align: top;
    text-align: left;
}
.content-table tbody tr:nth-child(even) {
    background: #f7fafc;
}
.content-table tbody tr:hover {
    background: #ebf4ff;
}

/* ===== Figure Placeholders ===== */
.fig-placeholder {
    margin: 24px 0;
    text-align: center;
}
.fig-placeholder img {
    height: auto;
    display: inline-block;
    border-radius: 6px;
}
.fig-placeholder-inner {
    min-height: 140px;
    background: linear-gradient(135deg, #fafcfe 0%, #f0f4f8 100%);
    border: 2px dashed #c3d5e8;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-accent);
    font-style: italic;
    font-size: 0.9em;
    font-weight: 500;
    padding: 24px;
    text-align: center;
    transition: border-color 0.3s ease, background 0.3s ease;
}
.fig-placeholder-inner:hover {
    border-color: var(--color-accent);
    background: linear-gradient(135deg, #ebf4ff 0%, #e8f0fe 100%);
}
.fig-placeholder figcaption {
    margin-top: 10px;
    text-align: justify;
    font-size: 0.88em;
    color: var(--color-text-secondary);
    font-style: italic;
    line-height: 1.5;
}

/* ===== Math Display Blocks ===== */
.math-block {
    margin: 18px 0;
    padding: 14px 22px;
    background: linear-gradient(90deg, #f0f7ff 0%, #f7fafc 100%);
    border-left: 3px solid var(--color-accent);
    border-radius: 0 6px 6px 0;
    overflow-x: auto;
}

/* ===== Ordered/Unordered Lists in tutorial text ===== */
.tutorial-text ol,
.tutorial-text ul {
    margin: 0.5em 0 1em 1.5em;
    line-height: 1.6;
}
.tutorial-text li {
    margin-bottom: 0.4em;
}

/* ===== Code Blocks ===== */
.code-block {
    margin: 12px 0;
    background: #1e1e2e;
    border-radius: 6px;
    overflow-x: auto;
    font-size: 0.82em;
    line-height: 1.55;
}
.code-block pre {
    margin: 0;
    padding: 16px 20px;
    color: #cdd6f4;
    font-family: 'Fira Code', 'Consolas', 'Monaco', monospace;
    white-space: pre;
    overflow-x: auto;
}
.code-block .comment { color: #6c7086; font-style: italic; }
.code-block .keyword { color: #cba6f7; }
.code-block .function { color: #89b4fa; }
.code-block .string { color: #a6e3a1; }
.code-block .number { color: #fab387; }
.code-block .decorator { color: #f9e2af; }
.code-block .builtin { color: #89dceb; }
.code-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 16px;
    background: #181825;
    border-radius: 6px 6px 0 0;
    font-size: 0.78em;
    color: #6c7086;
    font-family: var(--font-body);
}
.code-lang {
    font-weight: 700;
    color: #89b4fa;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.code-copy-btn {
    margin-left: auto;
    padding: 3px 10px;
    background: transparent;
    border: 1px solid #6c7086;
    border-radius: 4px;
    color: #cdd6f4;
    font-size: 0.9em;
    font-family: var(--font-body);
    cursor: pointer;
    transition: all 0.25s ease;
    white-space: nowrap;
}
.code-copy-btn:hover {
    background: rgba(137, 180, 250, 0.15);
    border-color: #89b4fa;
    color: #89b4fa;
}
.code-copy-btn.copied {
    border-color: #a6e3a1;
    color: #a6e3a1;
}

/* ===== Subsubsection Titles (h4 level) ===== */
.subsubsection-title {
    font-family: var(--font-heading);
    font-size: 1.05em;
    font-weight: 600;
    margin: 20px 0 10px 0;
    color: var(--color-text);
}

/* ===== Responsive additions ===== */
@media (max-width: 768px) {
    .viz-canvas { height: 220px; }
    .content-table { font-size: 0.85em; }
    .viz-controls { gap: 8px; }
    .collapsible-toggle { padding: 10px 14px; font-size: 0.9em; }
}