:root {
    --bg: #04131a;
    --bg-deep: #081d25;
    --panel: rgba(12, 31, 38, 0.82);
    --panel-strong: rgba(14, 41, 50, 0.94);
    --panel-soft: rgba(14, 33, 40, 0.72);
    --stroke: rgba(255, 255, 255, 0.09);
    --text: #f7f1e5;
    --muted: #9eb2b6;
    --sand: #f4c873;
    --teal: #63c7b0;
    --sky: #8eb4ff;
    --coral: #ff8b73;
    --cream: #efe5d0;
    --shadow: 0 30px 80px rgba(0, 0, 0, 0.32);
    --radius-xl: 30px;
    --radius-lg: 22px;
    --radius-md: 16px;
    --transition: 220ms ease;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    background:
        radial-gradient(circle at 20% 15%, rgba(99, 199, 176, 0.15), transparent 26%),
        radial-gradient(circle at 80% 10%, rgba(244, 200, 115, 0.16), transparent 23%),
        linear-gradient(180deg, #04131a 0%, #071820 38%, #0a2228 100%);
    color: var(--text);
    font-family: "Plus Jakarta Sans", sans-serif;
}

body::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 48px 48px;
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.45), transparent 95%);
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input,
textarea {
    font: inherit;
}

button {
    cursor: pointer;
}

.site-shell {
    width: min(1440px, calc(100% - 40px));
    margin: 0 auto;
    padding-bottom: 40px;
}

.topbar {
    position: sticky;
    top: 16px;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    padding: 16px 22px;
    margin-top: 18px;
    border: 1px solid var(--stroke);
    border-radius: 999px;
    background: rgba(6, 18, 24, 0.72);
    backdrop-filter: blur(18px);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.18);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    min-width: 0;
}

.brand-mark {
    display: grid;
    place-items: center;
    width: 46px;
    height: 46px;
    border-radius: 14px;
    background: linear-gradient(135deg, var(--sand), var(--teal));
    color: #062028;
    font-family: "Space Grotesk", sans-serif;
    font-weight: 700;
}

.brand strong,
.topnav a,
.primary-link,
.button-primary,
.button-secondary,
.panel-head h3,
.section-heading h2,
.hero h1,
.preview-card h2,
.inspector h3 {
    font-family: "Space Grotesk", sans-serif;
}

.brand small {
    display: block;
    color: var(--muted);
    font-size: 0.82rem;
}

.topnav {
    display: flex;
    align-items: center;
    gap: 22px;
    color: var(--muted);
}

.topnav a:hover,
.primary-link:hover {
    color: var(--text);
}

.primary-link {
    padding: 12px 18px;
    border-radius: 999px;
    border: 1px solid var(--stroke);
    background: rgba(255, 255, 255, 0.04);
    transition: var(--transition);
}

.hero {
    display: grid;
    grid-template-columns: minmax(0, 1.08fr) minmax(320px, 0.92fr);
    gap: 24px;
    padding: 44px 0 28px;
}

.hero-copy,
.preview-card,
.panel {
    border: 1px solid var(--stroke);
    background: var(--panel);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow);
}

.hero-copy {
    padding: 42px;
    border-radius: 36px;
}

.eyebrow,
.panel-kicker,
.preview-label,
.stage-label {
    margin: 0 0 12px;
    text-transform: uppercase;
    letter-spacing: 0.16em;
    font-size: 0.72rem;
    color: var(--muted);
}

.hero h1 {
    margin: 0;
    font-size: clamp(2.6rem, 5vw, 4.8rem);
    line-height: 0.96;
}

.hero-text {
    max-width: 62ch;
    margin: 20px 0 0;
    color: #d7dfde;
    line-height: 1.7;
    font-size: 1.03rem;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-top: 32px;
}

.button-primary,
.button-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 54px;
    padding: 0 22px;
    border-radius: 999px;
    transition: transform var(--transition), background var(--transition), color var(--transition);
}

.button-primary {
    background: linear-gradient(135deg, var(--sand), #f9df9b);
    color: #082028;
}

.button-secondary {
    border: 1px solid var(--stroke);
    background: rgba(255, 255, 255, 0.04);
}

.button-primary:hover,
.button-secondary:hover,
.system-card:hover,
.module-card:hover,
.bookmark-card:hover,
.hotspot:hover {
    transform: translateY(-2px);
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
    margin-top: 30px;
}

.hero-stats article {
    padding: 18px;
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.hero-stats strong {
    display: block;
    font-size: 1.8rem;
    font-family: "Space Grotesk", sans-serif;
}

.hero-stats span {
    color: var(--muted);
}

.hero-preview {
    display: grid;
    gap: 20px;
}

.preview-card {
    position: relative;
    overflow: hidden;
    border-radius: 32px;
    padding: 30px;
}

.preview-card::before {
    content: "";
    position: absolute;
    inset: auto -60px -70px auto;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(244, 200, 115, 0.28), transparent 70%);
}

.preview-card-main {
    min-height: 260px;
    background:
        linear-gradient(140deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02)),
        radial-gradient(circle at top left, rgba(99, 199, 176, 0.18), transparent 35%),
        var(--panel-strong);
}

.preview-card-small {
    background:
        linear-gradient(140deg, rgba(255, 255, 255, 0.04), rgba(255, 255, 255, 0.015)),
        radial-gradient(circle at top right, rgba(142, 180, 255, 0.14), transparent 30%),
        var(--panel-soft);
}

.preview-card h2 {
    margin: 0 0 12px;
    font-size: clamp(1.9rem, 4vw, 2.8rem);
}

.preview-card p:not(.preview-label) {
    color: #e4e8e2;
    line-height: 1.6;
}

.preview-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 22px;
}

.preview-tags span,
.panel-pill,
.inspector-badge,
.inspector-layer,
.stat-chip,
.layer-chip,
.stage-pill,
.bookmark-chip,
.module-meta span {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    background: rgba(255, 255, 255, 0.05);
    color: var(--text);
    font-size: 0.88rem;
}

.meter-row,
.preview-stack,
.panel-head,
.section-heading,
.viewer-toolbar,
.viewer-main,
.inspector-top,
.block-head,
.module-footer,
.quiz-footer,
.bookmark-card,
.bookmark-head,
.footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.meter-row span,
.preview-stack small,
.mini-dashboard span,
.stack-item p,
.module-card p,
.bookmark-card p,
.quiz-support,
.footer p {
    color: var(--muted);
}

.meter-bar {
    height: 10px;
    margin: 14px 0 18px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.07);
    overflow: hidden;
}

.meter-bar span {
    display: block;
    width: 0;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, var(--sand), var(--teal));
    transition: width 260ms ease;
}

.preview-stack {
    justify-content: flex-start;
    gap: 26px;
}

.preview-stack strong {
    display: block;
    margin-top: 6px;
    font-size: 1.35rem;
}

.workspace-section {
    padding: 10px 0 22px;
}

.section-heading {
    align-items: end;
    margin-bottom: 20px;
}

.section-heading h2 {
    margin: 0;
    font-size: clamp(1.8rem, 3vw, 2.8rem);
}

.workspace-controls {
    display: flex;
    align-items: center;
    gap: 14px;
    flex-wrap: wrap;
}

.search-field {
    display: grid;
    gap: 8px;
    min-width: min(100%, 320px);
    color: var(--muted);
    font-size: 0.84rem;
}

.search-field input {
    min-width: 300px;
    padding: 14px 18px;
    border-radius: 999px;
    border: 1px solid var(--stroke);
    background: rgba(255, 255, 255, 0.04);
    color: var(--text);
}

.view-toggle {
    display: inline-flex;
    padding: 6px;
    border-radius: 999px;
    border: 1px solid var(--stroke);
    background: rgba(255, 255, 255, 0.04);
}

.view-toggle button,
.layer-controls button,
.bookmark-button,
.quiz-choice,
.quiz-action,
.module-toggle {
    border: 0;
    transition: var(--transition);
}

.view-toggle button,
.layer-controls button {
    min-height: 42px;
    padding: 0 16px;
    border-radius: 999px;
    color: var(--muted);
    background: transparent;
}

.view-toggle button.is-active,
.layer-controls button.is-active {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text);
}

.workspace-grid,
.lower-grid {
    display: grid;
    gap: 20px;
}

.workspace-grid {
    grid-template-columns: minmax(280px, 0.9fr) minmax(0, 1.6fr);
}

.lower-grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.95fr) minmax(280px, 0.85fr);
    padding-top: 10px;
}

.panel {
    padding: 26px;
    border-radius: var(--radius-xl);
}

.systems-panel {
    display: grid;
    gap: 18px;
    align-content: start;
}

.system-grid,
.module-grid,
.bookmark-list {
    display: grid;
    gap: 12px;
}

.system-card,
.module-card,
.bookmark-card,
.stack-item,
.lesson-card,
.quiz-choice {
    border: 1px solid rgba(255, 255, 255, 0.08);
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-lg);
}

.system-card {
    display: grid;
    gap: 10px;
    padding: 18px;
    text-align: left;
}

.system-card.is-active {
    background: linear-gradient(140deg, rgba(255, 255, 255, 0.1), rgba(255, 255, 255, 0.04));
    border-color: rgba(255, 255, 255, 0.18);
}

.system-card small {
    color: var(--muted);
    line-height: 1.45;
}

.system-card strong,
.module-card h4,
.bookmark-card h4,
.quiz-question,
.stack-item strong,
.lesson-card strong {
    font-size: 1rem;
    font-weight: 700;
}

.mini-dashboard {
    display: grid;
    gap: 10px;
}

.mini-dashboard article {
    padding: 16px 18px;
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.06);
}

.mini-dashboard strong {
    display: block;
    margin-top: 6px;
    font-family: "Space Grotesk", sans-serif;
    font-size: 1.35rem;
}

.viewer-panel {
    display: grid;
    gap: 18px;
}

.viewer-toolbar {
    flex-wrap: wrap;
}

.layer-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.layer-controls button,
.bookmark-button,
.module-toggle,
.quiz-action {
    padding: 12px 18px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.04);
    color: var(--text);
}

.bookmark-button {
    border: 1px solid rgba(255, 255, 255, 0.08);
    margin-left: auto;
}

.bookmark-button.is-active {
    background: linear-gradient(135deg, rgba(244, 200, 115, 0.2), rgba(99, 199, 176, 0.2));
}

.viewer-main {
    align-items: stretch;
    gap: 18px;
}

.body-stage {
    position: relative;
    flex: 1 1 0;
    min-height: 760px;
    padding: 26px;
    border-radius: 30px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.04), rgba(255, 255, 255, 0.015)),
        rgba(6, 18, 23, 0.75);
    overflow: hidden;
}

.body-stage::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 50% 22%, var(--layer-glow), transparent 48%);
    pointer-events: none;
    transition: opacity 240ms ease;
}

.body-stage[data-layer="skeletal"] {
    --layer-glow: rgba(244, 200, 115, 0.22);
    --layer-accent: var(--sand);
}

.body-stage[data-layer="muscular"] {
    --layer-glow: rgba(255, 139, 115, 0.24);
    --layer-accent: var(--coral);
}

.body-stage[data-layer="nervous"] {
    --layer-glow: rgba(142, 180, 255, 0.24);
    --layer-accent: var(--sky);
}

.body-stage[data-layer="circulatory"] {
    --layer-glow: rgba(99, 199, 176, 0.26);
    --layer-accent: var(--teal);
}

.ambient-grid {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
    background-size: 32px 32px;
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.6), transparent 96%);
}

.figure-shell {
    position: relative;
    z-index: 1;
    height: 660px;
}

.figure-svg,
.hotspot-layer {
    position: absolute;
    inset: 0;
}

.figure-svg {
    width: 100%;
    height: 100%;
    opacity: 0;
    transform: scale(0.98);
    transition: opacity 260ms ease, transform 260ms ease;
}

.body-stage[data-view="front"] .figure-front,
.body-stage[data-view="back"] .figure-back {
    opacity: 1;
    transform: scale(1);
}

.silhouette {
    filter: drop-shadow(0 30px 60px rgba(0, 0, 0, 0.35));
}

.overlay {
    fill: none;
    stroke-width: 6px;
    stroke-linecap: round;
    stroke-linejoin: round;
    opacity: 0;
    transition: opacity 220ms ease;
    filter: drop-shadow(0 0 12px rgba(255, 255, 255, 0.08));
}

.body-stage[data-layer="skeletal"] .overlay-skeletal {
    opacity: 1;
    stroke: var(--sand);
}

.body-stage[data-layer="muscular"] .overlay-muscular {
    opacity: 1;
    stroke: var(--coral);
}

.body-stage[data-layer="nervous"] .overlay-nervous {
    opacity: 1;
    stroke: var(--sky);
}

.body-stage[data-layer="circulatory"] .overlay-circulatory {
    opacity: 1;
    stroke: var(--teal);
}

.hotspot-layer {
    pointer-events: none;
}

.hotspot {
    position: absolute;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 999px;
    background: rgba(8, 24, 30, 0.82);
    color: var(--text);
    transform: translate(-50%, -50%);
    pointer-events: auto;
}

.hotspot::before {
    content: "";
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--layer-accent);
    box-shadow: 0 0 0 7px color-mix(in srgb, var(--layer-accent) 16%, transparent);
}

.hotspot.is-selected {
    background: color-mix(in srgb, var(--layer-accent) 18%, rgba(8, 24, 30, 0.94));
    border-color: color-mix(in srgb, var(--layer-accent) 60%, white 8%);
}

.hotspot.is-hidden {
    opacity: 0.18;
}

.stage-footer {
    position: relative;
    z-index: 1;
    margin-top: 4px;
    padding-top: 16px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.inspector {
    width: min(100%, 390px);
    display: grid;
    gap: 16px;
    align-content: start;
    padding: 24px;
    border-radius: 30px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    background: rgba(8, 24, 30, 0.72);
}

.inspector h3 {
    margin: 0;
    font-size: 2rem;
}

.inspector-summary {
    margin: 0;
    color: #d4dcda;
    line-height: 1.68;
}

.stat-chip-row,
.lesson-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.inspector-block {
    display: grid;
    gap: 12px;
}

.block-head h4 {
    margin: 0;
    font-size: 1rem;
}

.stack-list {
    display: grid;
    gap: 10px;
}

.stack-item,
.lesson-card {
    padding: 14px 16px;
}

.stack-item strong,
.lesson-card strong,
.module-card h4,
.bookmark-card h4 {
    display: block;
    margin-bottom: 4px;
}

.stack-item p,
.lesson-card p,
.module-card p,
.bookmark-card p {
    margin: 0;
    line-height: 1.55;
}

.lesson-card {
    min-width: 140px;
}

textarea {
    width: 100%;
    resize: vertical;
    min-height: 120px;
    padding: 16px 18px;
    border-radius: 18px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    background: rgba(255, 255, 255, 0.04);
    color: var(--text);
    line-height: 1.55;
}

.path-panel,
.quiz-panel,
.bookmark-panel {
    display: grid;
    gap: 18px;
}

.module-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.module-card {
    padding: 18px;
    display: grid;
    gap: 12px;
}

.module-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.module-toggle.is-complete {
    background: linear-gradient(135deg, rgba(99, 199, 176, 0.2), rgba(244, 200, 115, 0.2));
}

.quiz-area {
    display: grid;
    gap: 16px;
}

.quiz-card {
    display: grid;
    gap: 16px;
    padding: 22px;
    border-radius: 26px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.quiz-question {
    margin: 0;
    font-size: 1.15rem;
    line-height: 1.5;
}

.quiz-choices {
    display: grid;
    gap: 12px;
}

.quiz-choice {
    width: 100%;
    padding: 14px 16px;
    text-align: left;
    color: var(--text);
}

.quiz-choice:hover {
    background: rgba(255, 255, 255, 0.09);
}

.quiz-choice.is-correct {
    background: rgba(99, 199, 176, 0.16);
}

.quiz-choice.is-wrong {
    background: rgba(255, 139, 115, 0.14);
}

.quiz-action {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.quiz-result {
    padding: 14px 16px;
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.05);
    line-height: 1.6;
}

.bookmark-list {
    align-content: start;
}

.bookmark-card {
    display: grid;
    gap: 12px;
    padding: 18px;
    align-items: start;
}

.bookmark-head {
    justify-content: flex-start;
    flex-wrap: wrap;
}

.bookmark-open {
    margin-top: 4px;
    padding: 12px 16px;
    border: 0;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--text);
}

.empty-state {
    padding: 20px;
    border-radius: 20px;
    border: 1px dashed rgba(255, 255, 255, 0.14);
    color: var(--muted);
    line-height: 1.65;
}

.footer {
    justify-content: center;
    margin-top: 24px;
    padding: 24px;
}

@media (max-width: 1180px) {
    .hero,
    .workspace-grid,
    .lower-grid,
    .viewer-main {
        grid-template-columns: 1fr;
        display: grid;
    }

    .inspector {
        width: 100%;
    }

    .module-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 860px) {
    .site-shell {
        width: min(100%, calc(100% - 24px));
    }

    .topbar {
        flex-wrap: wrap;
        border-radius: 28px;
        justify-content: center;
    }

    .topnav {
        order: 3;
        width: 100%;
        justify-content: center;
    }

    .hero-copy,
    .preview-card,
    .panel {
        padding: 20px;
        border-radius: 24px;
    }

    .hero-stats {
        grid-template-columns: 1fr;
    }

    .section-heading,
    .workspace-controls,
    .viewer-toolbar,
    .panel-head,
    .module-footer,
    .bookmark-head,
    .footer {
        align-items: start;
        flex-direction: column;
    }

    .search-field,
    .search-field input {
        width: 100%;
        min-width: 0;
    }

    .body-stage {
        min-height: 620px;
        padding: 18px;
    }

    .figure-shell {
        height: 500px;
    }

    .hotspot {
        padding: 8px 11px;
        font-size: 0.85rem;
    }
}