:root {
    --bg: #0a1018;
    --bg-elev: #101826;
    --bg-panel: #141e2e;
    --line: #1e2a3d;
    --line-strong: #2c3d56;
    --text: #e8eef7;
    --text-dim: #9aadc4;
    --text-mute: #6b7f99;
    --accent: #5aa2ff;
    --accent-2: #3d7fd9;
    --accent-ink: #0a1018;
    --accent-soft: rgba(90, 162, 255, 0.14);
    --ok: #5fd08a;
    --danger: #ef6b6b;
    --warn: #f0a35e;
    --font-display: "Newsreader", "Iowan Old Style", Georgia, serif;
    --font-body: "Inter", system-ui, -apple-system, sans-serif;
    --font-mono: "JetBrains Mono", ui-monospace, Menlo, monospace;
    --radius: 4px;
    --maxw: 1180px;
    --gutter: 28px;
    --section-pad: 64px;
}

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

html,
body {
    margin: 0;
    padding: 0;
}

body.surf-site {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    border-bottom: 1px solid var(--accent);
}

.wrap {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 var(--gutter);
}

/* Top bar */
.topbar {
    position: sticky;
    top: 0;
    z-index: 40;
    backdrop-filter: blur(12px);
    background: color-mix(in oklab, var(--bg) 88%, transparent);
    border-bottom: 1px solid var(--line);
}

.topbar-inner {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 14px var(--gutter);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.brand {
    display: flex;
    align-items: baseline;
    gap: 0.65rem;
}

.brand-name {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text);
}

.brand-sub {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--text-mute);
    letter-spacing: 0.04em;
}

.back-link {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--text-dim);
    letter-spacing: 0.04em;
    border-bottom: 1px solid transparent;
}

.back-link:hover {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

/* Hero */
.hero {
    padding: 56px 0 44px;
    border-bottom: 1px solid var(--line);
}

.hero h1 {
    font-family: var(--font-display);
    font-weight: 500;
    font-size: clamp(1.35rem, 2.55vw, 2.35rem);
    line-height: 1.25;
    letter-spacing: -0.02em;
    margin: 0 0 1.1rem;
    max-width: none;
    width: auto;
}

.hero-title-line {
    display: block;
    white-space: nowrap;
}

@media (max-width: 720px) {
    .hero-title-line {
        white-space: normal;
    }
}

.hero h1 .name-mark {
    font-family: var(--font-display);
    font-style: italic;
    font-weight: 500;
    color: var(--accent);
}

.hero h1 u {
    text-decoration: underline;
    text-underline-offset: 0.12em;
    text-decoration-thickness: 1.5px;
    color: inherit;
    font-style: inherit;
}

.authors {
    color: var(--text-dim);
    font-size: 0.98rem;
    font-family: var(--font-body);
    font-weight: 400;
    margin-bottom: 0.35rem;
}

.hero-venue {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.4rem 0.55rem;
    margin: 0 0 1.45rem;
    color: var(--text-dim);
    font-size: 0.9rem;
    line-height: 1.45;
}

.hero-venue i {
    font-style: italic;
    color: #ff9a3c;
}

.hero-venue-place {
    color: #ff9a3c;
}

.hero-venue .dot {
    display: inline-block;
    width: 5px;
    height: 5px;
    border-radius: 999px;
    background: #ff9a3c;
    flex-shrink: 0;
}

.hero-venue .badge-acceptance {
    display: inline-flex;
    align-items: center;
    gap: 0.35em;
    padding: 0.28em 0.7em;
    border-radius: 999px;
    background: linear-gradient(145deg, #c41e4a 0%, #9b1538 100%);
    color: #fff;
    font-family: var(--font-body);
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    box-shadow: 0 1px 4px rgba(155, 21, 56, 0.35);
}

.hero-venue .badge-acceptance-star {
    color: #ffd56a;
    font-size: 0.82em;
    line-height: 1;
    filter: drop-shadow(0 0 3px rgba(255, 213, 106, 0.7));
}

.authors a,
.authors a:hover,
.authors a:visited,
.authors strong,
.authors span,
.authors .text-body {
    color: inherit !important;
    font-family: inherit !important;
    font-weight: 400 !important;
    font-style: normal !important;
    text-decoration: none !important;
    border-bottom: none !important;
}

.authors .author-note {
    background: transparent;
    color: var(--text-mute) !important;
    font-size: 0.85em;
    font-family: inherit;
    font-weight: 400;
    white-space: nowrap;
}

.affils {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--text-mute);
    margin-bottom: 0.7rem;
}

.btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.7rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.52rem 1.2rem;
    border: 1px solid var(--line-strong);
    border-radius: 999px;
    background: var(--bg-panel);
    color: var(--text);
    font-size: 0.88rem;
    font-weight: 600;
    line-height: 1.2;
}

.btn i {
    font-size: 1.12rem;
    line-height: 1;
}

a.btn:hover {
    border-color: var(--accent);
    border-bottom-color: var(--accent);
    color: var(--accent);
}

.btn.primary {
    background: #e8eef7;
    border-color: #e8eef7;
    color: var(--accent-ink);
}

a.btn.primary:hover {
    background: #fff;
    border-color: #fff;
    border-bottom-color: #fff;
    color: var(--accent-ink);
}

.btn.muted {
    color: var(--text-mute);
    cursor: default;
}

.btn.muted:hover {
    border-color: var(--line-strong);
    color: var(--text-mute);
}

/* Overview animations */
.overview {
    padding: 36px 0 48px;
    border-bottom: 1px solid var(--line);
}

.overview-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.1rem;
}

@media (max-width: 900px) {
    .overview-grid {
        grid-template-columns: 1fr;
    }
}

.viz-card {
    position: relative;
    background: linear-gradient(180deg, #121d2d 0%, var(--bg-elev) 100%);
    border: 1px solid #263751;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 14px 34px rgba(0, 0, 0, 0.18), inset 0 1px 0 rgba(255, 255, 255, 0.025);
    transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.viz-card::before {
    content: "";
    position: absolute;
    inset: 0 0 auto;
    z-index: 1;
    height: 1px;
    background: linear-gradient(90deg, transparent 8%, rgba(112, 174, 250, 0.6), transparent 92%);
    pointer-events: none;
}

@media (hover: hover) {
    .viz-card:hover {
        transform: translateY(-3px);
        border-color: #355176;
        box-shadow: 0 18px 42px rgba(0, 0, 0, 0.26), 0 0 28px rgba(90, 162, 255, 0.045);
    }
}

.viz-stage {
    position: relative;
    width: 100%;
    aspect-ratio: 5 / 4;
    background:
        linear-gradient(rgba(98, 138, 190, 0.025) 1px, transparent 1px),
        linear-gradient(90deg, rgba(98, 138, 190, 0.025) 1px, transparent 1px),
        radial-gradient(ellipse at 50% 0%, rgba(90, 162, 255, 0.14), transparent 58%),
        linear-gradient(180deg, #0e1725 0%, #090f17 100%);
    background-size: 24px 24px, 24px 24px, auto, auto;
}

.viz-stage svg {
    display: block;
    width: 100%;
    height: 100%;
}

#sc-los-packet,
#sc-nlos-packet,
#sc-diff-packet,
#sc-diff-hit,
#sc-hit,
#sc-source,
#nehf-net-packet,
#nehf-query-ground,
#nehf-query-top {
    filter: drop-shadow(0 0 4px currentColor);
}

#nehf-scan,
#ex-point-scan {
    filter: drop-shadow(0 0 3px rgba(120, 184, 255, 0.65));
}

.viz-caption {
    display: flex;
    align-items: baseline;
    gap: 0.55rem;
    padding: 0.78rem 0.95rem 0.82rem;
    border-top: 1px solid var(--line);
    font-size: 0.86rem;
    font-weight: 600;
    color: var(--text);
}

.viz-caption .num {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--accent);
    letter-spacing: 0.08em;
    border: 1px solid rgba(90, 162, 255, 0.28);
    border-radius: 999px;
    padding: 0.08rem 0.38rem;
    background: rgba(90, 162, 255, 0.07);
}

.overview-note {
    margin: 1rem 0 0;
    text-align: center;
    font-size: 0.88rem;
    color: var(--text-mute);
}

/* Sections */
section.block {
    padding: var(--section-pad) 0;
    border-bottom: 1px solid var(--line);
}

.section-head {
    margin-bottom: 1.35rem;
}

.section-title {
    font-family: var(--font-mono);
    font-size: clamp(0.95rem, 1.6vw, 1.1rem);
    font-weight: 500;
    letter-spacing: 0.02em;
    text-transform: none;
    line-height: 1.35;
    margin: 0;
    color: var(--accent);
}

.prose {
    color: var(--text-dim);
    max-width: none;
    width: 100%;
}

.prose p {
    margin: 0 0 1rem;
}

.prose p:last-child {
    margin-bottom: 0;
}

.prose strong {
    color: var(--text);
    font-weight: 600;
}

.abstract-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    gap: clamp(1rem, 1.8vw, 1.5rem);
    align-items: center;
}

.abstract-copy {
    position: relative;
    padding-left: 2rem;
    line-height: 1.55;
}

.abstract-copy::before {
    content: "";
    position: absolute;
    top: 0.72rem;
    bottom: 0.72rem;
    left: 0.37rem;
    width: 1px;
    background: linear-gradient(180deg, rgba(90, 162, 255, 0.9), rgba(90, 162, 255, 0.2));
}

.abstract-copy p {
    position: relative;
    margin-bottom: 0.6rem;
}

.abstract-copy p::before {
    content: "";
    position: absolute;
    top: 0.55rem;
    left: calc(-2rem + 0.04rem);
    width: 0.72rem;
    height: 0.72rem;
    border: 2px solid #8bc1ff;
    border-radius: 50%;
    background: var(--bg);
    box-shadow: 0 0 0 4px rgba(90, 162, 255, 0.08), 0 0 10px rgba(90, 162, 255, 0.28);
}

.abstract-copy p:last-child {
    margin-bottom: 0;
}

.abstract-framework {
    min-width: 0;
    margin: 0;
    padding: 0.5rem;
    background: #f7f9fc;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    box-shadow: 0 16px 38px rgba(0, 0, 0, 0.2);
}

.abstract-framework img {
    display: block;
    width: 100%;
    height: auto;
    border-radius: 5px;
}

@media (max-width: 900px) {
    .abstract-layout {
        grid-template-columns: 1fr;
        align-items: start;
    }

    .abstract-framework {
        width: min(100%, 680px);
        margin-inline: auto;
    }
}

/* Split layouts: text left, media right */
.split-row {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 1.5rem;
    align-items: start;
}

@media (max-width: 900px) {
    .split-row {
        grid-template-columns: 1fr;
    }
}

/* Shared light panel around a group of figures */
.fig-panel {
    margin-top: 1.35rem;
    background: #f3f6fa;
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 10px;
    padding: 1rem 1.05rem 0.85rem;
}

.split-row .fig-panel {
    margin-top: 0;
}

/* Figures */
.fig-grid {
    display: grid;
    gap: 0.85rem;
    margin-top: 0;
}

.fig-grid--4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    width: 100%;
    align-items: center;
}

.fig-grid--3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.recon-row {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
    gap: 0.85rem;
    margin-top: 1.35rem;
}

.recon-scene {
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
}

.recon-scene-name {
    text-align: center;
    font-family: var(--font-mono);
    font-size: 0.92rem;
    letter-spacing: 0.01em;
    color: var(--text-mute);
    font-weight: 500;
    line-height: 1.3;
}

.recon-panel {
    margin-top: 0;
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0.45rem;
    padding: 0.55rem;
    align-items: start;
}

.recon-panel .fig {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.recon-panel .fig figcaption {
    margin-top: 0.35rem;
    text-align: center;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.01em;
    color: #5a6570;
    font-weight: 500;
    line-height: 1.25;
}

@media (max-width: 900px) {
    .recon-row {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
}

.fig-panel--brdf {
    width: 68%;
    max-width: 68%;
    margin-left: auto;
    margin-right: auto;
}

.fig-grid--brdf {
    grid-template-columns: minmax(0, 1fr) minmax(0, 3fr);
    align-items: center;
}

@media (max-width: 800px) {
    .fig-panel--brdf {
        width: 100%;
        max-width: 100%;
    }
}

@media (max-width: 800px) {
    .fig-grid--4 {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .fig-grid--3,
    .fig-grid--brdf {
        grid-template-columns: 1fr;
    }
}

.fig {
    margin: 0;
}

.fig img {
    display: block;
    width: 100%;
    height: auto;
    background: transparent;
}

.fig figcaption {
    margin-top: 0.4rem;
    text-align: center;
    font-size: 0.78rem;
    color: #5a6570;
    line-height: 1.4;
}

.recon .fig-media {
    aspect-ratio: 1 / 1;
    overflow: hidden;
    background: transparent;
}

.recon .fig img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
}

/* Real-world comparison: labels outside, one shared white panel for all images */
.cmp-table {
    margin-top: 1.35rem;
    display: grid;
    gap: 0.65rem;
    overflow-x: auto;
    min-width: 0;
}

.cmp-row,
.cmp-body {
    display: grid;
    grid-template-columns: 7.5rem minmax(0, 1fr);
    gap: 0.65rem;
    align-items: stretch;
    min-width: 720px;
}

.cmp-labels {
    display: grid;
    grid-template-rows: repeat(3, minmax(0, 1fr));
    align-items: center;
}

.cmp-head-cells,
.cmp-panel {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 0.5rem;
    align-items: center;
}

.cmp-head-cells {
    padding: 0 0.55rem;
}

.cmp-panel {
    margin-top: 0;
    padding: 0.55rem;
}

.cmp-head .cmp-cell {
    text-align: center;
    font-family: var(--font-mono);
    font-size: 0.92rem;
    letter-spacing: 0.01em;
    text-transform: none;
    color: var(--text-mute);
    font-weight: 500;
}

.cmp-label {
    font-family: var(--font-mono);
    font-size: 0.92rem;
    letter-spacing: 0.01em;
    text-transform: none;
    color: var(--text-dim);
    font-weight: 500;
    line-height: 1.3;
    padding-right: 0.25rem;
}

.cmp-label--ours,
.cmp-label--ours .cmp-ours {
    color: var(--accent);
}

.cmp-ours {
    display: inline-block;
    margin-top: 0.15rem;
    font-size: 0.86rem;
}

.cmp-cell {
    margin: 0;
    min-width: 0;
}

.realworld .fig-media {
    overflow: hidden;
    border-radius: 4px;
    background: transparent;
}

.realworld .fig img {
    width: 100%;
    height: auto;
    display: block;
}

@media (max-width: 800px) {
    .cmp-row,
    .cmp-body {
        grid-template-columns: 6.2rem minmax(0, 1fr);
    }
}

.tikzjax-wrap {
    width: 100%;
    overflow-x: auto;
    text-align: center;
    min-height: 2rem;
    background: #ffffff;
    border: 1px solid #d5dbe3;
    border-radius: 10px;
    padding: 1rem 1rem 0.75rem;
}

.tikzjax-wrap svg {
    max-width: 100%;
    height: auto;
    filter: none;
}

.fig-note {
    margin: 0.65rem 0 0;
    text-align: center;
    font-size: 0.78rem;
    color: #5a6570;
}

.tikzjax-wrap .fig-note {
    color: #5a6570;
}

/* Citation */
.cite-panel {
    background: var(--bg-elev);
    border: 1px solid var(--line);
    border-radius: 6px;
    overflow: hidden;
}

.cite-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.7rem 0.9rem;
    border-bottom: 1px solid var(--line);
}

.cite-head span {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-mute);
    letter-spacing: 0.06em;
}

.copy-btn {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--accent);
    background: transparent;
    border: 1px solid var(--line-strong);
    border-radius: var(--radius);
    padding: 0.28rem 0.6rem;
    cursor: pointer;
}

.copy-btn:hover {
    border-color: var(--accent);
}

.cite-panel pre {
    margin: 0;
    padding: 1rem 1.1rem;
    overflow-x: auto;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    line-height: 1.55;
    color: var(--text-dim);
    white-space: pre;
}

.page-end {
    padding: 28px 0 48px;
    text-align: center;
}

.page-end a {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-mute);
}

.page-end a:hover {
    color: var(--accent);
}

.star {
    animation: twinkle 3.2s ease-in-out infinite;
}

@keyframes twinkle {
    0%, 100% { opacity: 0.35; }
    50% { opacity: 1; }
}

@media (prefers-reduced-motion: reduce) {
    .viz-card,
    .star {
        animation: none;
        transition: none;
    }
}