@import url(https://fonts.googleapis.com/css?family=Righteous);

:root {
    --surface-bg: rgba(255, 255, 255, 0.03);
    --surface-border: rgba(255, 255, 255, 0.1);
    --surface-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    --page-title: hsl(0 0% 90%);
    --panel-title: hsl(0 0% 95%);
    --section-title: hsl(0 0% 90%);
    --copy-color: hsl(0 0% 80%);
    --description-color: hsl(0 0% 75%);
    --hint-color: hsl(0 0% 70%);
    --panel-subtext: hsl(0 0% 68%);
    --nav-bg: rgba(0, 0, 0, 0.4);
    --nav-border: rgba(255, 255, 255, 0.1);
    --footer-border: rgba(255, 255, 255, 0.05);
    --footer-text: rgba(255, 255, 255, 0.4);
    --scroll-track: rgba(255, 255, 255, 0.05);
    --scroll-thumb: rgba(255, 255, 255, 0.2);
    --scroll-thumb-hover: rgba(255, 255, 255, 0.3);
    --tree-canvas-bg: rgba(0, 0, 0, 0.1);
    --tree-node-bg: rgba(255, 255, 255, 0.2);
    --tree-node-border: rgba(255, 255, 255, 0.42);
    --tree-node-text: #fff;
    --tree-edge: rgba(255, 255, 255, 0.2);
    --node-label-color: hsl(0 0% 80%);
    --edge-label-bg: rgba(0, 0, 0, 0.7);
    --edge-label-text: #4ECDC4;
    --edge-label-border: transparent;
    --cw-bg: rgba(0, 0, 0, 0.6);
    --cw-text: hsl(48 90% 60%);
    --cw-border: rgba(255, 255, 255, 0.2);
    --active-accent: #4ECDC4;
    --step-card-bg: rgba(255, 255, 255, 0.04);
    --step-card-border: rgba(255, 255, 255, 0.12);
    --result-accent: #f59e0b;
    --party0-accent: #3b82f6;
    --party1-accent: #ef4444;
    --input-bg: rgba(0, 0, 0, 0.2);
    --input-border: rgba(255, 255, 255, 0.2);
    --input-text: #f8fafc;
    --input-placeholder: rgba(226, 232, 240, 0.62);
    --status-log-bg: rgba(0, 0, 0, 0.3);
    --status-log-text: hsl(122 40% 70%);
    --status-log-border: rgba(255, 255, 255, 0.08);
}

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

body {
    font-family: "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background:
        radial-gradient(at 50% 0, transparent, #080808),
        repeating-conic-gradient(
            hsla(0, 0%, 0%, 0.235) 0% 25%,
            transparent 0% 50%
        ) 0 0 / 0.375em 0.375em,
        #3b3b3b;
    min-height: 100vh;
    color: #333;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
}

body.day-mode {
    background: #f0f4f8;
    background-image: url(../../../../assets/image/day-background.png);
    background-size: auto;
    background-repeat: repeat;
    --surface-bg: rgba(255, 255, 255, 0.78);
    --surface-border: rgba(0, 0, 0, 0.1);
    --page-title: #2d3748;
    --panel-title: #2d3748;
    --section-title: #1a202c;
    --copy-color: #1a202c;
    --description-color: #4a5568;
    --hint-color: #718096;
    --panel-subtext: #4a5568;
    --nav-bg: rgba(255, 255, 255, 0.7);
    --nav-border: rgba(0, 0, 0, 0.1);
    --footer-border: rgba(0, 0, 0, 0.1);
    --footer-text: rgba(0, 0, 0, 0.5);
    --scroll-track: rgba(0, 0, 0, 0.05);
    --scroll-thumb: rgba(0, 0, 0, 0.2);
    --scroll-thumb-hover: rgba(0, 0, 0, 0.3);
    --tree-canvas-bg: linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(241, 245, 249, 0.98));
    --tree-node-bg: rgba(255, 255, 255, 0.8);
    --tree-node-border: rgba(0, 0, 0, 0.2);
    --tree-node-text: #1a202c;
    --tree-edge: rgba(0, 0, 0, 0.15);
    --node-label-color: #4a5568;
    --edge-label-bg: rgba(255, 255, 255, 0.8);
    --edge-label-text: #059669;
    --edge-label-border: #ccc;
    --cw-bg: rgba(255, 255, 255, 0.9);
    --cw-text: #d97706;
    --cw-border: #ccc;
    --step-card-bg: rgba(255, 255, 255, 0.75);
    --step-card-border: rgba(0, 0, 0, 0.08);
    --input-bg: rgba(255, 255, 255, 0.96);
    --input-border: rgba(148, 163, 184, 0.62);
    --input-text: #0f172a;
    --input-placeholder: rgba(100, 116, 139, 0.78);
    --status-log-bg: rgba(255, 255, 255, 0.94);
    --status-log-text: #14532d;
    --status-log-border: rgba(148, 163, 184, 0.4);
}

#background-wrapper {
    display: none;
}

.page-container {
    width: 100%;
    max-width: 120rem;
    margin: 0 auto;
    padding: 20px 1rem;
    position: relative;
    z-index: 2;
    flex: 1;
}

.container {
    max-width: 95%;
    margin: 0 auto;
    padding: 20px;
}

.navbar {
    position: sticky;
    top: 0;
    z-index: 50;
    width: 100%;
    align-self: stretch;
    background-color: var(--nav-bg);
    border-bottom: 1px solid var(--nav-border);
    backdrop-filter: blur(12px) saturate(1.2);
    -webkit-backdrop-filter: blur(12px) saturate(1.2);
}

.nav-content {
    max-width: 80rem;
    margin: 0 auto;
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.logo-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
}

.logo-icon {
    width: 2.25rem;
    height: 2.25rem;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
}

.logo-text-desktop {
    font-family: "Righteous", "Microsoft YaHei", sans-serif;
    font-size: 1.125rem;
    font-weight: 900;
    letter-spacing: 0.05em;
    color: hsl(0 0% 95%);
}

body.day-mode .logo-text-desktop {
    color: #1a202c;
    font-weight: 700;
    text-shadow: none;
}

.nav-actions {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 1rem;
    flex: 1;
    flex-wrap: wrap;
}

.nav-btn,
.btn {
    -webkit-tap-highlight-color: transparent;
    cursor: pointer;
    position: relative;
    isolation: isolate;
    color: white;
    background: transparent;
    border: 1px solid transparent;
    border-radius: 12px;
    font-weight: 500;
    transition-property: translate, scale;
    transition-duration: 0.1s;
    transition-timing-function: ease-out;
}

.nav-btn::before,
.nav-btn::after,
.btn::before,
.btn::after {
    content: "";
    position: absolute;
    inset: -1px;
    border-radius: inherit;
    pointer-events: none;
}

.nav-btn::before,
.btn::before {
    z-index: -1;
    background: linear-gradient(
        hsl(0 0% 100% / 0.18),
        hsl(0 0% 4% / 0.7)
    );
    backdrop-filter: saturate(2) contrast(1) blur(10px);
    -webkit-backdrop-filter: saturate(2) contrast(1) blur(10px);
}

.nav-btn::after,
.btn::after {
    box-shadow: 0 0 1px 0.8px hsl(0 0% 100% / 0.8) inset;
    mask: linear-gradient(-35deg, #ffffff80, #ffffff30 30% 60%, #fff);
    -webkit-mask: linear-gradient(-35deg, #ffffff80, #ffffff30 30% 60%, #fff);
}

.nav-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    text-decoration: none;
}

.btn {
    padding: 12px 24px;
    font-size: 1rem;
    flex: 1;
    min-width: 120px;
}

.nav-btn:hover:not(:disabled),
.btn:hover:not(:disabled) {
    scale: 1.02;
}

.nav-btn:active:not(:disabled),
.btn:active:not(:disabled) {
    scale: 0.98;
    translate: 0 1px;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

body.day-mode .nav-btn,
body.day-mode .btn {
    background: #ffffff;
    color: #1a202c;
    border: 2px solid #cbd5e0;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

body.day-mode .nav-btn::before,
body.day-mode .btn::before {
    background: none;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
}

body.day-mode .nav-btn::after {
    display: none;
}

body.day-mode .nav-btn:hover:not(:disabled),
body.day-mode .btn:hover:not(:disabled) {
    background: #f7fafc;
    border-color: #a0aec0;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

header {
    text-align: center;
    margin-bottom: 40px;
}

header h1 {
    display: inline-block;
    position: relative;
    margin-bottom: 1rem;
    line-height: 1.2;
    font-family: "Righteous", "Microsoft YaHei", serif;
    font-size: 3.5em;
    color: var(--page-title);
    text-shadow: 0.03em 0.03em 0 hsla(230, 40%, 50%, 1);
}

header h1::after {
    content: attr(data-shadow);
    position: absolute;
    top: 0.06em;
    left: 0.06em;
    width: 100%;
    height: 100%;
    z-index: -1;
    display: flex;
    justify-content: center;
    align-items: center;
    white-space: nowrap;
    text-shadow: none;
    background-image: linear-gradient(
        45deg,
        transparent 45%,
        hsla(48, 20%, 90%, 1) 45%,
        hsla(48, 20%, 90%, 1) 55%,
        transparent 0
    );
    background-size: 0.05em 0.05em;
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: shad-anim 60s linear infinite;
}

body.day-mode header h1 {
    text-shadow: 0.03em 0.03em 0 hsla(200, 60%, 60%, 1);
}

@keyframes shad-anim {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: 100% -100%;
    }
}

.description {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1rem;
    color: var(--description-color);
}

.main-container {
    display: flex;
    flex-direction: column;
    gap: 30px;
    margin-bottom: 40px;
}

.input-section,
.output-section {
    width: 100%;
}

.input-card,
.output-card,
.explanation {
    background: var(--surface-bg);
    border: 1px solid var(--surface-border);
    border-radius: 16px;
    box-shadow: var(--surface-shadow);
    backdrop-filter: blur(20px) saturate(1.2);
    -webkit-backdrop-filter: blur(20px) saturate(1.2);
}

.input-card,
.output-card {
    padding: 25px;
}

.input-card h2,
.output-header h2,
.explanation h2 {
    color: var(--panel-title);
}

.input-card h2,
.output-header h2 {
    margin-bottom: 20px;
    font-size: 1.5rem;
}

.output-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.output-section {
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.output-card--visualizer {
    overflow: hidden;
    height: clamp(600px, 76vh, 760px);
}

.output-card--formula {
    min-height: 260px;
}

.online-stage {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.tree-stage-view,
.tree-stage-grid {
    flex: 1 1 auto;
    min-height: 0;
}

.tree-stage-view {
    overflow: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    touch-action: pan-x pan-y;
}

.tree-stage-grid {
    overflow: hidden;
}

.party-stage {
    flex: 1 1 320px;
    min-width: 0;
    min-height: 0;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.party-stage__viewport {
    flex: 1 1 auto;
    min-height: 0;
    overflow: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    touch-action: pan-x pan-y;
}

.party-stage__title,
.party-stage > h3 {
    margin-bottom: 5px;
    text-align: center;
    font-size: 1rem;
}

.party-stage__title--p0,
.party-stage:first-child > h3 {
    color: var(--party0-accent);
}

.party-stage__title--p1,
.party-stage:last-child > h3 {
    color: var(--party1-accent);
}

.output-header--panel {
    margin-bottom: 10px;
}

.panel-intro {
    margin-bottom: 12px;
    color: var(--panel-subtext);
    font-size: 0.84rem;
    line-height: 1.45;
}

.formula-window__body,
.result-window__body {
    padding: 0;
    overflow-y: auto;
    overflow-x: hidden;
}

.formula-window__body {
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-height: 520px;
}

.calc-empty {
    padding: 18px 14px;
    border: 1px dashed rgba(255, 255, 255, 0.16);
    border-radius: 12px;
    color: var(--panel-subtext);
    text-align: center;
    font-size: 0.92rem;
}

body.day-mode .calc-empty {
    border-color: rgba(0, 0, 0, 0.12);
}

.calc-section {
    margin-top: 4px;
    padding: 6px 4px 2px;
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--cw-text);
}

.calc-step {
    display: grid;
    grid-template-columns: minmax(0, 1.25fr) minmax(120px, 0.95fr);
    gap: 10px;
    padding: 12px;
    border: 1px solid var(--step-card-border);
    border-radius: 12px;
    background: var(--step-card-bg);
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.28s ease, transform 0.28s ease, border-color 0.28s ease;
}

.calc-step.visible {
    opacity: 1;
    transform: translateY(0);
}

.calc-step--p0 {
    border-left: 4px solid var(--party0-accent);
}

.calc-step--p1 {
    border-left: 4px solid var(--party1-accent);
}

.calc-step--cw {
    border-left: 4px solid var(--result-accent);
}

.calc-step--result {
    border-left: 4px solid var(--active-accent);
}

.calc-step__meta {
    grid-column: 1 / -1;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 8px;
}

.calc-step__badge {
    padding: 2px 8px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.08);
    color: hsl(0 0% 96%);
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

body.day-mode .calc-step__badge {
    background: rgba(0, 0, 0, 0.06);
    color: #1a202c;
}

.calc-step__title {
    margin: 0;
    flex: 1 1 auto;
    min-width: 0;
    color: var(--panel-title);
    font-size: 0.94rem;
    line-height: 1.4;
}

.calc-step__panel {
    min-width: 0;
}

.calc-step__panel--rhs {
    padding-left: 10px;
    border-left: 1px solid rgba(255, 255, 255, 0.08);
}

body.day-mode .calc-step__panel--rhs {
    border-left-color: rgba(0, 0, 0, 0.08);
}

.calc-step__label {
    margin-bottom: 4px;
    color: var(--panel-subtext);
    font-size: 0.74rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.calc-step__content {
    display: flex;
    flex-direction: column;
    gap: 5px;
    color: var(--copy-color);
    font-size: 0.9rem;
}

.calc-step__content .katex {
    color: inherit;
    font-size: 1em;
}

.calc-step__content .katex-display {
    margin: 0.15em 0;
    overflow-x: auto;
    overflow-y: hidden;
}

.result-card__formula .katex-display {
    margin: 0.15em 0;
    overflow-x: auto;
    overflow-y: hidden;
}

.result-window__body {
    display: grid;
    gap: 10px;
}

.result-card {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 12px;
    align-items: center;
    padding: 12px;
    border: 1px solid var(--step-card-border);
    border-radius: 12px;
    background: var(--step-card-bg);
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.28s ease, transform 0.28s ease, border-color 0.28s ease;
}

.result-card.visible {
    opacity: 1;
    transform: translateY(0);
}

.result-card--one {
    border-color: rgba(78, 205, 196, 0.55);
    box-shadow: 0 0 0 1px rgba(78, 205, 196, 0.18) inset;
}

.result-card__index {
    min-width: 44px;
    text-align: center;
    padding: 6px 10px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--panel-title);
    font-weight: 700;
}

body.day-mode .result-card__index {
    background: rgba(0, 0, 0, 0.06);
}

.result-card__formula {
    min-width: 0;
    color: var(--copy-color);
}

.result-card__formula .katex {
    color: inherit;
}

.result-card__value {
    min-width: 54px;
    text-align: center;
    padding: 6px 10px;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 800;
    color: #fff;
    background: rgba(148, 163, 184, 0.32);
}

.result-card--one .result-card__value {
    background: rgba(78, 205, 196, 0.85);
}

.result-card--zero .result-card__value {
    background: rgba(100, 116, 139, 0.55);
}

.format-options {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 15px;
    padding: 15px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 8px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-label {
    color: var(--panel-title);
    font-weight: 700;
    font-size: 0.96rem;
}

.control-input {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--input-border);
    border-radius: 10px;
    background: var(--input-bg);
    color: var(--input-text);
    font-size: 1.05rem;
}

.control-input::placeholder {
    color: var(--input-placeholder);
}

.control-input:focus {
    outline: none;
    border-color: rgba(78, 205, 196, 0.72);
    box-shadow: 0 0 0 3px rgba(78, 205, 196, 0.18);
}

.control-input:disabled {
    opacity: 0.75;
    cursor: not-allowed;
}

body.day-mode .control-input {
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.35);
}

.status-log {
    color: var(--status-log-text);
    background: var(--status-log-bg);
    border: 1px solid var(--status-log-border);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.upload-hint {
    font-size: 0.9rem;
    color: var(--hint-color);
}

.output-buttons {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: 20px;
}

.explanation {
    padding: 30px;
}

.explanation h2 {
    margin-bottom: 25px;
    text-align: center;
    font-size: 1.8rem;
}

.explanation-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.explanation-item {
    padding: 20px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 10px;
}

.explanation-item h3 {
    margin-bottom: 10px;
    font-size: 1.2rem;
    color: var(--section-title);
}

.explanation-item p {
    color: var(--copy-color);
    line-height: 1.6;
}

body.day-mode .explanation h2,
body.day-mode .explanation-item h3 {
    font-weight: 600;
}

body.day-mode .explanation-item p {
    font-weight: 500;
}

.explanation [data-latex-scope] .katex {
    color: inherit;
}

.explanation [data-latex-scope] .katex-display {
    margin: 0.35em 0;
    overflow-x: auto;
    overflow-y: hidden;
}

.theme-toggle-container {
    width: 60px;
    height: 34px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.theme-toggle {
    --theme-toggle-scale: 0.45;
    position: relative;
    z-index: 1;
    user-select: none;
    transform: scale(var(--theme-toggle-scale));
    transform-origin: center;
}

.theme-toggle__checkbox {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    clip-path: inset(50%);
    white-space: nowrap;
    border: 0;
}

.theme-toggle__btn {
    display: block;
    position: relative;
    width: 125px;
    height: 70px;
    border-radius: 70px;
    border: 5px solid #1c1c1c;
    background-color: #3c4145;
    cursor: pointer;
    transition: all 350ms ease-in;
}

.theme-toggle__checkbox:focus-visible + .theme-toggle__btn {
    outline: 3px solid rgba(255, 255, 255, 0.8);
    outline-offset: 4px;
}

body.day-mode .theme-toggle__checkbox:focus-visible + .theme-toggle__btn {
    outline-color: rgba(0, 0, 0, 0.55);
}

.theme-toggle__btn::before {
    content: "";
    position: absolute;
    top: 2px;
    left: 2px;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    background-color: #fff;
    border: 5px solid #e3e3c7;
    transition: all 250ms ease-in;
}

.theme-toggle__btn::after {
    content: "";
    position: absolute;
    top: 62%;
    left: 39px;
    z-index: 10;
    width: 9.2px;
    height: 9.2px;
    opacity: 0;
    background-color: #fff;
    border-radius: 50%;
    box-shadow:
        #fff 0 0,
        #fff 2.5px 0,
        #fff 5px 0,
        #fff 7.5px 0,
        #fff 9px 0,
        #fff 11.5px 0,
        #fff 13px 0,
        #fff 17px -1px 0 1px,
        #fff 13px -6px 0 -2px,
        #fff 6px -6px 0 1px,
        #d3d3d3 0 0 0 3.5px,
        #d3d3d3 5px 0 0 3.5px,
        #d3d3d3 9px 0 0 3.5px,
        #d3d3d3 13px 0 0 3.5px,
        #d3d3d3 17px -1px 0 4.5px,
        #d3d3d3 13px -6px 0 1px,
        #d3d3d3 6px -6px 0 4.5px;
    transition: opacity 100ms ease-in;
}

.theme-toggle__feature {
    display: block;
    position: absolute;
    top: 9px;
    left: 52.5%;
    z-index: 20;
    width: 4px;
    height: 4px;
    border-radius: 50%;
    background-color: #fff;
    box-shadow:
        rgba(255, 255, 255, 0.1) 30px -3px 0 0,
        rgba(255, 255, 255, 0.1) 12px 10px 0 -1px,
        #fff 38px 18px 0 1px,
        rgba(255, 255, 255, 0.1) 32px 34px 0 0,
        #fff 20px 24px 0 -1.5px,
        rgba(255, 255, 255, 0.1) 5px 38px 0 1px;
    animation: starry-star 5s ease-in-out infinite;
}

.theme-toggle__feature::before {
    content: "";
    position: absolute;
    top: -2px;
    left: -25px;
    width: 15px;
    height: 15px;
    background-color: #fff;
    border: 4px solid #e3e3c7;
    border-radius: 50%;
    box-shadow:
        #e3e3c7 -28px 0 0 -3px,
        #e3e3c7 -8px 24px 0 -2px;
    transform-origin: -6px 130%;
    transition: all 250ms ease-in;
}

@keyframes starry-star {
    50% {
        background-color: rgba(255, 255, 255, 0.1);
        box-shadow:
            #fff 30px -3px 0 0,
            #fff 12px 10px 0 -1px,
            rgba(255, 255, 255, 0.1) 38px 18px 0 1px,
            #fff 32px 34px 0 0,
            rgba(255, 255, 255, 0.1) 20px 24px 0 -1.5px,
            #fff 5px 38px 0 1px;
    }
}

@keyframes bounce-in {
    0% {
        opacity: 0;
        transform: scale(0.3);
    }

    50%,
    55% {
        opacity: 1;
        transform: scale(1.1);
    }

    75% {
        transform: scale(0.9);
    }

    100% {
        opacity: 1;
        transform: scale(1);
    }
}

.theme-toggle__checkbox:checked + .theme-toggle__btn {
    background-color: #9ee3fb;
    border-color: #86c3d7;
}

.theme-toggle__checkbox:checked + .theme-toggle__btn::before {
    left: 57px;
    background-color: #ffdf6d;
    border-color: #e1c348;
}

.theme-toggle__checkbox:checked + .theme-toggle__btn::after {
    opacity: 1;
    animation-name: bounce-in;
    animation-duration: 0.6s;
    animation-delay: 0.1s;
    animation-fill-mode: backwards;
    animation-timing-function: ease-in-out;
}

.theme-toggle__checkbox:checked + .theme-toggle__btn .theme-toggle__feature {
    opacity: 0;
    box-shadow:
        rgba(255, 255, 255, 0.1) 30px -3px 0 -4px,
        rgba(255, 255, 255, 0.1) 12px 10px 0 -5px,
        #fff 38px 18px 0 -3px,
        rgba(255, 255, 255, 0.1) 32px 34px 0 -4px,
        #fff 20px 24px 0 -5.5px,
        rgba(255, 255, 255, 0.1) 5px 38px 0 -3px;
    animation: none;
}

.theme-toggle__checkbox:checked + .theme-toggle__btn .theme-toggle__feature::before {
    left: 25px;
    transform: rotate(70deg);
}

.tree-canvas {
    position: relative;
    width: max-content;
    min-width: 100%;
    flex: 1;
    background: var(--tree-canvas-bg);
    border: 1px solid var(--surface-border);
    border-radius: 8px;
    overflow: visible;
    scroll-behavior: smooth;
}

.tree-node {
    position: absolute;
    width: 88px;
    height: 56px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: var(--tree-node-bg);
    border: 1px solid var(--tree-node-border);
    border-radius: 6px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    transform: translate(-50%, -50%);
    transition: all 0.5s ease;
    z-index: 10;
    opacity: 0;
    color: var(--tree-node-text);
    font-size: 0.78rem;
    line-height: 1.18;
    text-align: center;
}

.tree-node.offline-node {
    width: 112px;
    height: 76px;
    font-size: 0.74rem;
}

.tree-node.visible {
    opacity: 1;
}

.tree-node.active-path {
    border: 2px solid var(--active-accent);
    box-shadow: 0 0 15px rgba(78, 205, 196, 0.6);
}

.tree-node.eval-p0 {
    background: rgba(59, 130, 246, 0.3);
    border-color: #3b82f6;
}

.tree-node.eval-p1 {
    background: rgba(239, 68, 68, 0.3);
    border-color: #ef4444;
}

.tree-node .katex {
    color: inherit;
    font-size: 1.02em;
}

.tree-node .katex-display {
    margin: 0;
}

.node-label {
    position: absolute;
    top: -28px;
    font-size: 0.84rem;
    font-weight: 600;
    color: var(--node-label-color);
    white-space: nowrap;
}

.node-value {
    width: 100%;
    padding: 0 4px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
}

.tree-edge {
    position: absolute;
    height: 2px;
    background: var(--tree-edge);
    transform-origin: 0 50%;
    transition: all 0.5s ease;
    z-index: 5;
    opacity: 0;
}

.tree-edge.visible {
    opacity: 1;
}

.tree-edge.active-path {
    height: 3px;
    background: var(--active-accent);
    box-shadow: 0 0 8px rgba(78, 205, 196, 0.5);
}

.edge-label {
    position: absolute;
    z-index: 6;
    opacity: 0;
    transform: translate(-50%, -50%);
    transition: opacity 0.5s ease;
    padding: 2px 6px;
    border: 1px solid var(--edge-label-border);
    border-radius: 4px;
    background: var(--edge-label-bg);
    color: var(--edge-label-text);
    font-size: 0.78rem;
    font-weight: 700;
}

.edge-label.visible {
    opacity: 1;
}

.cw-label {
    position: absolute;
    left: 16px;
    width: 160px;
    padding: 8px;
    z-index: 20;
    opacity: 0;
    transform: translateY(-50%);
    transition: opacity 0.5s ease;
    border: 1px solid var(--cw-border);
    border-radius: 6px;
    background: var(--cw-bg);
    color: var(--cw-text);
    font-family: monospace;
    font-size: 0.78rem;
    text-align: center;
}

.cw-label.visible {
    opacity: 1;
}

.cw-label .katex {
    color: inherit;
    font-size: 1em;
}

.cw-label .katex-display {
    margin: 0.2em 0;
}

.footer {
    width: 100%;
    margin-top: 3rem;
    padding: 2rem 1rem;
    position: relative;
    z-index: 1;
    text-align: center;
    border-top: 1px solid var(--footer-border);
}

.footer p {
    margin: 0;
    line-height: 1.8;
    font-size: 0.85rem;
    color: var(--footer-text);
    transition: color 300ms ease-out;
}

::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--scroll-track);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: var(--scroll-thumb);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--scroll-thumb-hover);
}

@media (max-width: 768px) {
    .page-container {
        padding: 10px 1rem;
    }

    header h1 {
        font-size: 2rem;
    }

    .main-container {
        gap: 20px;
    }

    .output-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .output-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .explanation-content {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .theme-toggle {
        --theme-toggle-scale: 0.42;
    }

    .footer {
        padding: 1.5rem 1rem;
    }

    .footer p {
        font-size: 0.75rem;
    }
}

@media (max-width: 639px) {
    .nav-content {
        flex-direction: column;
        align-items: center;
        gap: 0.75rem;
        padding: 0.75rem 1rem;
    }

    .logo-wrapper {
        width: 100%;
        justify-content: center;
    }

    .nav-actions {
        width: 100%;
        justify-content: center;
        gap: 0.75rem;
    }
}

@media (max-width: 480px) {
    .container,
    .input-card,
    .output-card,
    .explanation {
        padding: 15px;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .tree-node {
        width: 80px;
        height: 52px;
        font-size: 0.72rem;
    }

    .tree-node.offline-node {
        width: 102px;
        height: 72px;
        font-size: 0.7rem;
    }

    .node-label {
        top: -24px;
        font-size: 0.78rem;
    }

    .edge-label,
    .cw-label {
        font-size: 0.72rem;
    }

    .calc-step,
    .result-card {
        grid-template-columns: 1fr;
    }

    .calc-step__panel--rhs {
        padding-left: 0;
        border-left: 0;
        border-top: 1px solid rgba(255, 255, 255, 0.08);
        padding-top: 10px;
    }

    body.day-mode .calc-step__panel--rhs {
        border-top-color: rgba(0, 0, 0, 0.08);
    }

    .result-card__value,
    .result-card__index {
        justify-self: start;
    }

    .cw-label {
        width: 150px;
    }
}