:root {
    --bg-color: #eef0f2;
    --sidebar-bg: rgba(255, 255, 255, 0.25);
    --card-bg: rgba(255, 255, 255, 0.2);
    --text-color: #2c3e50;
    --heading-color: #000000;
    --subtle-text-color: rgba(44, 62, 80, 0.6);
    --border-color: rgba(0, 0, 0, 0.08);
    --shadow-color: rgba(0, 0, 0, 0.04);
    --shadow-color-hover: rgba(0, 0, 0, 0.1);
    --table-header-bg: rgba(0, 0, 0, 0.02);
    --blockquote-bg: rgba(0, 0, 0, 0.02);
    --blockquote-border: rgba(0, 0, 0, 0.1);
    --scrollbar-thumb-bg: rgba(0, 0, 0, 0.25);
    --scrollbar-track-bg: transparent;
    --slider-bg: rgba(0, 0, 0, 0.2);
    --slider-checked-bg: #000000;
    --nav-active-bg: rgba(0, 0, 0, 0.04);
    --icon-stroke-color: rgba(0, 0, 0, 0.5);
    --icon-stroke-color-active: #000000;
    --spotlight-color: rgba(0, 0, 0, 0.04);
    --tooltip-bg: #1a1a1a;
    --tooltip-text-color: #f0f0f0;
    --progress-bar-bg: #000000;
    --highlight-bg: #ffdd77;
    --highlight-text: #000000;
}

html[data-theme='dark'] {
    --bg-color: #1a1d21;
    --sidebar-bg: rgba(20, 22, 25, 0.35);
    --card-bg: rgba(26, 29, 33, 0.3);
    --text-color: #bdc3c7;
    --heading-color: #ffffff;
    --subtle-text-color: rgba(236, 240, 241, 0.5);
    --border-color: rgba(255, 255, 255, 0.1);
    --shadow-color: rgba(0, 0, 0, 0.15);
    --shadow-color-hover: rgba(0, 0, 0, 0.25);
    --table-header-bg: rgba(255, 255, 255, 0.04);
    --blockquote-bg: rgba(255, 255, 255, 0.03);
    --blockquote-border: rgba(255, 255, 255, 0.15);
    --scrollbar-thumb-bg: rgba(255, 255, 255, 0.25);
    --slider-bg: rgba(255, 255, 255, 0.2);
    --slider-checked-bg: #ffffff;
    --nav-active-bg: rgba(255, 255, 255, 0.06);
    --icon-stroke-color: rgba(255, 255, 255, 0.5);
    --icon-stroke-color-active: #ffffff;
    --spotlight-color: rgba(255, 255, 255, 0.05);
    --tooltip-bg: #ecf0f1;
    --tooltip-text-color: #1a1a1a;
    --progress-bar-bg: #ffffff;
    --highlight-bg: #d4a017;
    --highlight-text: #000000;
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Roboto', -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.7;
    font-size: 16px;
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background-color 0.4s ease, color 0.4s ease;
    overflow-x: hidden;
}

.app-container {
    display: flex;
}

#sidebar {
    width: 300px;
    flex-shrink: 0;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 0.4s ease, border-color 0.4s ease, transform 0.4s ease;
    z-index: 100;
    -webkit-backdrop-filter: blur(24px);
    backdrop-filter: blur(24px);
    will-change: transform;
}

.sidebar-header {
    padding: 25px 30px;
    display: flex;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}

.sidebar-logo-icon {
    width: 32px;
    height: 32px;
    stroke: var(--heading-color);
    transition: stroke 0.4s ease, transform 0.3s ease;
}

.sidebar-header:hover .sidebar-logo-icon {
    transform: scale(1.1);
}

.sidebar-header h1 {
    font-size: 1.25rem;
    color: var(--heading-color);
    margin-left: 15px;
    font-weight: 500;
}

.sidebar-search-container {
    padding: 20px 30px 10px;
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}

#search-input {
    width: 100%;
    padding: 10px 15px;
    font-size: 0.9rem;
    background-color: rgba(0,0,0,0.04);
    border: 1px solid transparent;
    border-radius: 6px;
    color: var(--text-color);
    transition: all 0.3s ease;
    font-family: 'Roboto', sans-serif;
}
html[data-theme='dark'] #search-input {
    background-color: rgba(255,255,255,0.06);
}

#search-input:focus, #search-input:focus-visible {
    outline: none;
    background-color: transparent;
    border-color: var(--border-color);
    box-shadow: 0 0 0 2px var(--nav-active-bg);
}

.search-results-info {
    font-size: 0.8rem;
    color: var(--subtle-text-color);
    padding: 8px 0;
    height: 28px;
    transition: opacity 0.3s ease;
}

#toc-nav {
    overflow-y: auto;
    flex-grow: 1;
    padding: 20px 0;
}

#toc-nav ul {
    list-style: none;
}

#toc-nav li {
    transition: opacity 0.3s ease, max-height 0.3s ease, transform 0.3s ease;
    transform-origin: top;
    will-change: opacity, max-height, transform;
}

#toc-nav li.is-hidden {
    opacity: 0;
    max-height: 0 !important;
    overflow: hidden;
    pointer-events: none;
    transform: scaleY(0);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 30px;
    color: var(--subtle-text-color);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s ease, background-color 0.2s ease;
    position: relative;
}

.nav-link::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%) scaleY(0);
    height: 100%;
    width: 3px;
    background-color: var(--heading-color);
    transition: transform 0.3s ease, background-color 0.4s ease;
    border-radius: 0 3px 3px 0;
    will-change: transform;
}

.nav-icon-container {
    flex-shrink: 0;
    width: 20px;
    height: 20px;
    display: grid;
    place-items: center;
}

.nav-svg {
    width: 100%;
    height: 100%;
    stroke: var(--icon-stroke-color);
    transition: stroke 0.2s ease, transform 0.2s ease;
}

#toc-nav li ul {
    padding-left: 15px;
    border-left: 1px solid var(--border-color);
    margin-left: 30px;
    margin-top: 5px;
    margin-bottom: 5px;
}

#toc-nav li ul .nav-link {
    font-size: 0.85rem;
    font-weight: 400;
    padding: 8px 15px;
    gap: 10px;
}

.nav-link:hover {
    color: var(--heading-color);
}

.nav-link:hover .nav-svg {
    stroke: var(--icon-stroke-color-active);
    transform: scale(1.1);
}

.nav-link.active-link {
    color: var(--heading-color);
    background-color: var(--nav-active-bg);
}

.nav-link.active-link::before {
    transform: translateY(-50%) scaleY(1);
}

.nav-link.active-link .nav-svg {
    stroke: var(--icon-stroke-color-active);
}

.sidebar-footer {
    padding: 20px 30px;
    border-top: 1px solid var(--border-color);
}

.theme-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 28px;
}

.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--slider-bg);
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    will-change: transform;
}

input:checked + .slider {
    background-color: var(--slider-checked-bg);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}

input:checked + .slider:before {
    transform: translateX(22px);
}

#content-pane {
    margin-left: 300px;
    width: calc(100% - 300px);
    padding: 50px 60px;
}

.content-card, .part-divider {
    opacity: 0;
    transform: translateY(40px);
    will-change: opacity, transform;
}

.part-divider {
    padding: 20px 0;
    margin-top: 60px;
    margin-bottom: 30px;
    border-bottom: 1px solid var(--border-color);
}

.part-divider h2 {
    color: var(--heading-color);
    font-size: 2.2rem;
    font-weight: 300;
}

.content-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    margin-bottom: 40px;
    transition: background-color 0.4s ease, border-color 0.4s ease, box-shadow 0.3s ease, transform 0.3s ease;
    box-shadow: 0 10px 30px var(--shadow-color);
    position: relative;
    overflow: hidden;
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    will-change: transform, box-shadow;
}

.content-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    background: radial-gradient(
        circle 400px at var(--mouse-x) var(--mouse-y),
        var(--spotlight-color) 0%,
        transparent 100%
    );
    opacity: 0;
    transition: opacity 0.3s ease;
    will-change: opacity;
}

.content-card:hover::after {
    opacity: 1;
}

.content-card:hover {
    box-shadow: 0 15px 40px var(--shadow-color-hover);
    transform: translateY(-5px);
    border-color: rgba(0,0,0,0.12);
}
html[data-theme='dark'] .content-card:hover {
    border-color: rgba(255,255,255,0.18);
}

.content-card.is-hidden-by-search {
    display: none;
}

.content-card header {
    padding: 30px 40px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 25px;
    cursor: pointer;
    position: relative;
}

.content-card[data-state="closed"] header {
    border-bottom-color: transparent;
}

.content-card header > div {
    flex-grow: 1;
}

.content-card#intro header > h2 {
    flex-grow: 1;
    font-weight: 500;
    font-size: 1.6rem;
}

.module-toggle-icon {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    color: var(--subtle-text-color);
    transition: transform 0.4s cubic-bezier(0.2, 1, 0.3, 1), color 0.2s ease;
    will-change: transform;
}

.module-toggle-icon svg {
    width: 100%;
    height: 100%;
    stroke: currentColor;
}

.content-card:hover .module-toggle-icon {
    color: var(--heading-color);
}

.content-card[data-state="closed"] .module-toggle-icon {
    transform: rotate(-90deg);
}

.module-svg {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    stroke: var(--icon-stroke-color-active);
    transition: stroke 0.4s ease;
}

.content-card header h3 {
    color: var(--heading-color);
    margin-bottom: 8px;
    font-size: 1.5rem;
    font-weight: 500;
}

.content-card .module-intro {
    font-size: 1rem;
    color: var(--subtle-text-color);
    font-style: italic;
    font-weight: 300;
}

.content-body {
    padding: 30px 40px 35px;
    will-change: height, padding, opacity;
}

.content-card[data-state="closed"] .content-body {
    max-height: 0;
    padding-top: 0;
    padding-bottom: 0;
    overflow: hidden;
    opacity: 0;
}

.content-body section, .content-body > div {
    margin-bottom: 30px;
}

.content-body section:last-child, .content-body > div:last-child {
    margin-bottom: 0;
}

.content-body h4, .content-body h5 {
    color: var(--heading-color);
    margin-bottom: 15px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border-color);
}

.content-body h4 { font-size: 1.2rem; font-weight: 500; }
.content-body h5 { font-size: 1.1rem; font-weight: 500; }

p, ul, ol {
    margin-bottom: 1.2rem;
}

ul, ol {
    padding-left: 25px;
}

li {
    margin-bottom: 0.8rem;
}

strong {
    font-weight: 500;
    color: var(--heading-color);
}

blockquote {
    background-color: var(--blockquote-bg);
    border-left: 3px solid var(--blockquote-border);
    padding: 20px 25px;
    margin: 25px 0;
    border-radius: 0 8px 8px 0;
    font-size: 0.95rem;
}

.internal-link {
    color: var(--heading-color);
    font-weight: 500;
    text-decoration: none;
    background-image: linear-gradient(var(--heading-color), var(--heading-color));
    background-position: 0% 100%;
    background-repeat: no-repeat;
    background-size: 0% 1px;
    transition: background-size .3s, color .3s;
    position: relative;
}

.internal-link:hover, .internal-link:focus-visible {
    background-size: 100% 1px;
    outline: none;
}

.interactive-tooltip {
    position: absolute;
    z-index: 110;
    background-color: var(--tooltip-bg);
    color: var(--tooltip-text-color);
    padding: 8px 12px;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 400;
    line-height: 1.4;
    max-width: 300px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    opacity: 0;
    transform: translateY(10px);
    pointer-events: none;
    transition: opacity 0.2s ease, transform 0.2s ease;
    will-change: opacity, transform;
}

.table-container {
    overflow-x: auto;
    margin: 25px 0;
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

table {
    width: 100%;
    border-collapse: collapse;
    min-width: 700px;
}

th, td {
    padding: 15px 20px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

thead th {
    background-color: var(--table-header-bg);
    font-weight: 500;
    color: var(--heading-color);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

tbody tr {
    transition: background-color 0.2s ease;
}

tbody tr:last-of-type td {
    border-bottom: none;
}

tbody tr:hover {
    background-color: var(--nav-active-bg);
}

::-webkit-scrollbar {
  width: 12px;
}

::-webkit-scrollbar-track {
  background: var(--scrollbar-track-bg);
}

::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb-bg);
  border-radius: 6px;
  border: 3px solid var(--bg-color);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--subtle-text-color);
}

#mobile-nav-toggle {
    display: none;
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 101;
    width: 44px;
    height: 44px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
}

#mobile-nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background-color: var(--heading-color);
    margin: 4px auto;
    transition: all 0.3s ease-in-out;
    border-radius: 2px;
    will-change: transform, opacity;
}

#mobile-nav-toggle.is-active span:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
}
#mobile-nav-toggle.is-active span:nth-child(2) {
    opacity: 0;
}
#mobile-nav-toggle.is-active span:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
}

#progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background-color: var(--progress-bar-bg);
    width: 0%;
    z-index: 200;
    transition: background-color 0.4s ease;
    will-change: width;
}

mark {
    background-color: var(--highlight-bg);
    color: var(--highlight-text);
    padding: 0.1em 0.2em;
    border-radius: 3px;
    transition: background-color 0.4s ease, color 0.4s ease;
}

@media (max-width: 1200px) {
    #content-pane {
        padding: 40px;
    }
}

@media (max-width: 992px) {
    body {
        font-size: 16px;
    }

    #sidebar {
        transform: translateX(-100%);
        z-index: 99;
    }

    body.sidebar-open #sidebar {
        transform: translateX(0);
        box-shadow: 5px 0px 15px rgba(0,0,0,0.1);
    }
    
    #content-pane {
        margin-left: 0;
        width: 100%;
    }

    #mobile-nav-toggle {
        display: block;
    }
}

@media (max-width: 768px) {
    #content-pane {
        padding: 30px 20px;
    }
    .content-card header {
        flex-direction: row;
        align-items: flex-start;
        gap: 15px;
        padding: 20px;
    }
    .module-svg {
        width: 36px;
        height: 36px;
        margin-top: 4px;
    }
    .content-body {
        padding: 20px 20px 25px;
    }
    .part-divider h2 {
        font-size: 1.8rem;
    }
    .content-card header h3 {
        font-size: 1.3rem;
    }
}