:root {
    --bg: #0a0e1a;
    --surface: #111827;
    --surface2: #1a2235;
    --border: #1e2d45;
    --accent1: #00d4ff;
    --accent2: #a855f7;
    --accent3: #34d399;
    --accent4: #fbbf24;
    --accent5: #f87171;
    --text: #ffffff;
    --text-muted: #94a3b8;
    --text-dim: #e2e8f0;
    --card-glow1: rgba(0, 212, 255, 0.08);
    --card-glow2: rgba(124, 58, 237, 0.08);
    --card-glow3: rgba(16, 185, 129, 0.08);
    --card-glow4: rgba(245, 158, 11, 0.08);
    --card-glow5: rgba(239, 68, 68, 0.08);
    --accent6: #06b6d4;
    --card-glow6: rgba(6, 182, 212, 0.08);
}

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

body {
    background: var(--bg);
    color: var(--text);
    font-family: 'Noto Sans Sinhala', sans-serif;
    overflow-x: hidden;
    min-height: 100vh;
}

/* Animated background grid */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(rgba(0, 212, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 212, 255, 0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
}

/* Floating orbs */
.orb {
    position: fixed;
    border-radius: 50%;
    filter: blur(80px);
    pointer-events: none;
    z-index: 0;
    animation: orbFloat 20s ease-in-out infinite;
}

.orb1 {
    width: 400px;
    height: 400px;
    background: rgba(0, 212, 255, 0.06);
    top: -100px;
    left: -100px;
    animation-delay: 0s;
}

.orb2 {
    width: 300px;
    height: 300px;
    background: rgba(124, 58, 237, 0.06);
    bottom: 20%;
    right: -80px;
    animation-delay: -7s;
}

.orb3 {
    width: 250px;
    height: 250px;
    background: rgba(16, 185, 129, 0.05);
    top: 50%;
    left: 40%;
    animation-delay: -14s;
}

@keyframes orbFloat {

    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }

    33% {
        transform: translate(30px, -30px) scale(1.1);
    }

    66% {
        transform: translate(-20px, 20px) scale(0.95);
    }
}

/* Header */
header {
    position: relative;
    z-index: 10;
    text-align: center;
    padding: 70px 20px 50px;
    overflow: hidden;
}

.header-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(0, 212, 255, 0.1);
    border: 1px solid rgba(0, 212, 255, 0.3);
    border-radius: 50px;
    padding: 6px 18px;
    font-size: 0.78rem;
    color: var(--accent1);
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 24px;
    animation: fadeDown 0.8s ease both;
}

.header-badge span {
    width: 6px;
    height: 6px;
    background: var(--accent1);
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
        transform: scale(1);
    }

    50% {
        opacity: 0.5;
        transform: scale(1.5);
    }
}

h1 {
    font-family: 'Syne', sans-serif;
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    line-height: 1.1;
    animation: fadeDown 0.8s 0.1s ease both;
    background: linear-gradient(135deg, #fff 30%, var(--accent1));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-dim);
    animation: fadeDown 0.8s 0.2s ease both;
    margin-bottom: 16px;
}

.java-tag {
    display: inline-block;
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-family: 'JetBrains Mono', monospace;
    font-size: 1rem;
    font-weight: 600;
    animation: fadeDown 0.8s 0.3s ease both;
}

@keyframes fadeDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Nav Pills */
.nav-pills {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    padding: 0 20px 50px;
    position: relative;
    z-index: 10;
    animation: fadeUp 0.8s 0.4s ease both;
}

.nav-pill {
    cursor: pointer;
    padding: 10px 22px;
    border-radius: 50px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text-dim);
    font-size: 0.85rem;
    font-family: 'Noto Sans Sinhala', sans-serif;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-pill:hover {
    border-color: var(--accent1);
    color: var(--accent1);
    transform: translateY(-2px);
}

.nav-pill.active {
    background: var(--accent1);
    border-color: var(--accent1);
    color: #000;
    font-weight: 600;
}

.pill-num {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    font-weight: 700;
    font-family: 'JetBrains Mono', monospace;
}

.nav-pill.active .pill-num {
    background: rgba(0, 0, 0, 0.2);
}

@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Main content */
main {
    position: relative;
    z-index: 10;
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px 80px;
}

/* Concept Cards */
.concept-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 24px;
    margin-bottom: 40px;
    overflow: hidden;
    transition: all 0.5s ease;
    animation: cardIn 0.6s ease both;
    position: relative;
}

.concept-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 24px;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
}

.concept-card:hover::before {
    opacity: 1;
}

.concept-card:hover {
    transform: translateY(-4px);
    border-color: rgba(255, 255, 255, 0.1);
}

.c1::before {
    background: var(--card-glow1);
}

.c2::before {
    background: var(--card-glow2);
}

.c3::before {
    background: var(--card-glow3);
}

.c4::before {
    background: var(--card-glow4);
}

.c5::before {
    background: var(--card-glow5);
}

.c6::before {
    background: var(--card-glow6);
}

.c1 {
    --accent: var(--accent1);
}

.c2 {
    --accent: var(--accent2);
}

.c3 {
    --accent: var(--accent3);
}

.c4 {
    --accent: var(--accent4);
}

.c5 {
    --accent: var(--accent5);
}

.c6 {
    --accent: var(--accent6);
}

@keyframes cardIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Card Header */
.card-header {
    padding: 30px 36px 24px;
    display: flex;
    align-items: flex-start;
    gap: 20px;
    border-bottom: 1px solid var(--border);
    position: relative;
    overflow: hidden;
}

.card-header::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), transparent);
}

.concept-icon {
    width: 56px;
    height: 56px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    flex-shrink: 0;
    border: 1px solid rgba(255, 255, 255, 0.1);
    animation: iconPop 0.5s 0.3s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

@keyframes iconPop {
    from {
        opacity: 0;
        transform: scale(0.5) rotate(-15deg);
    }

    to {
        opacity: 1;
        transform: scale(1) rotate(0);
    }
}

.c1 .concept-icon {
    background: rgba(0, 212, 255, 0.1);
    border-color: rgba(0, 212, 255, 0.3);
}

.c2 .concept-icon {
    background: rgba(124, 58, 237, 0.1);
    border-color: rgba(124, 58, 237, 0.3);
}

.c3 .concept-icon {
    background: rgba(16, 185, 129, 0.1);
    border-color: rgba(16, 185, 129, 0.3);
}

.c4 .concept-icon {
    background: rgba(245, 158, 11, 0.1);
    border-color: rgba(245, 158, 11, 0.3);
}

.c6 .concept-icon {
    background: rgba(6, 182, 212, 0.1);
    border-color: rgba(6, 182, 212, 0.3);
}

/* Interface vs Abstract comparison table */
.compare-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: 14px;
    overflow: hidden;
    margin-bottom: 28px;
    font-size: 0.82rem;
}

.compare-table th {
    padding: 12px 16px;
    text-align: left;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.72rem;
    letter-spacing: 1px;
    text-transform: uppercase;
    background: var(--surface2);
    border-bottom: 1px solid var(--border);
}

.compare-table th:first-child {
    color: var(--accent6);
}

.compare-table th:nth-child(2) {
    color: #a78bfa;
}

.compare-table th:nth-child(3) {
    color: #f87171;
}

.compare-table td {
    padding: 11px 16px;
    border-bottom: 1px solid rgba(30, 45, 69, 0.6);
    color: var(--text-dim);
    background: rgba(26, 34, 53, 0.5);
    vertical-align: top;
}

.compare-table tr:last-child td {
    border-bottom: none;
}

.compare-table tr:hover td {
    background: rgba(6, 182, 212, 0.04);
}

.yes-badge {
    color: #4ade80;
    font-weight: 600;
}

.no-badge {
    color: #f87171;
    font-weight: 600;
}

/* Interface diagram */
.interface-diagram {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
}

.iface-box {
    background: linear-gradient(135deg, rgba(6, 182, 212, 0.15), rgba(6, 182, 212, 0.05));
    border: 2px dashed rgba(6, 182, 212, 0.5);
    border-radius: 14px;
    padding: 16px 28px;
    text-align: center;
    min-width: 260px;
}

.iface-box .cls-type {
    font-size: 0.68rem;
    color: var(--accent6);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
}

.iface-box .cls-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: #fff;
    margin: 4px 0;
}

.iface-box .cls-methods {
    font-size: 0.78rem;
    color: var(--text-muted);
    line-height: 1.7;
}

.impl-arrow-row {
    display: flex;
    gap: 60px;
    align-items: flex-start;
    position: relative;
    margin-top: 0;
}

.impl-arrow-row::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 220px;
    height: 2px;
    background: rgba(6, 182, 212, 0.35);
}

.impl-branch {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.impl-line {
    width: 2px;
    height: 28px;
    background: rgba(6, 182, 212, 0.35);
}

.impl-class {
    background: var(--surface2);
    border: 1px solid rgba(6, 182, 212, 0.3);
    border-radius: 12px;
    padding: 14px 18px;
    text-align: center;
    min-width: 155px;
    transition: all 0.3s;
}

.impl-class:hover {
    border-color: var(--accent6);
    transform: translateY(3px);
}

.impl-class .cls-type {
    font-size: 0.65rem;
    color: rgba(6, 182, 212, 0.7);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
}

.impl-class .cls-name {
    font-size: 0.95rem;
    font-weight: 700;
    color: #fff;
    margin: 3px 0;
}

.impl-class .cls-methods {
    font-size: 0.75rem;
    color: var(--accent6);
}

.impl-class .impl-note {
    font-size: 0.72rem;
    color: var(--text-muted);
    font-style: italic;
    margin-top: 3px;
}

.impl-keyword {
    font-size: 0.68rem;
    color: var(--accent6);
    font-family: 'JetBrains Mono', monospace;
    background: rgba(6, 182, 212, 0.1);
    border-radius: 4px;
    padding: 2px 7px;
    margin: 5px 0 0;
    display: inline-block;
}

.s6 {
    background: rgba(6, 182, 212, 0.05);
}

.s6:hover {
    background: rgba(6, 182, 212, 0.12);
    border-color: rgba(6, 182, 212, 0.4);
}

.header-text {
    flex: 1;
}

.concept-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.72rem;
    color: var(--accent);
    letter-spacing: 3px;
    text-transform: uppercase;
    margin-bottom: 6px;
    display: block;
}

.concept-title {
    font-family: 'Syne', sans-serif;
    font-size: 1.6rem;
    font-weight: 800;
    color: #fff;
    margin-bottom: 4px;
}

.concept-sinhala {
    font-size: 0.95rem;
    color: var(--accent);
    opacity: 0.85;
}

/* Card Body */
.card-body {
    padding: 30px 36px;
}

/* Definition Box */
.definition-box {
    background: var(--surface2);
    border-left: 3px solid var(--accent);
    border-radius: 0 12px 12px 0;
    padding: 18px 22px;
    margin-bottom: 28px;
    font-size: 0.95rem;
    line-height: 1.8;
    color: var(--text-dim);
}

.definition-box strong {
    color: var(--accent);
}

/* Example Box */
.example-box {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 20px 22px;
    margin-bottom: 28px;
    position: relative;
    overflow: hidden;
}

.example-label {
    font-size: 0.7rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent);
    font-family: 'JetBrains Mono', monospace;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.example-label::before {
    content: '';
    width: 16px;
    height: 1px;
    background: var(--accent);
}

.example-text {
    font-size: 0.93rem;
    line-height: 1.85;
    color: var(--text-dim);
}

/* Visual Diagram */
.diagram-area {
    margin-bottom: 28px;
}

.diagram-title {
    font-size: 0.75rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--text-muted);
    font-family: 'JetBrains Mono', monospace;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.diagram-title::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
}

/* Blueprint diagram for Class/Object */
.blueprint-diagram {
    display: grid;
    grid-template-columns: 1fr auto 1fr 1fr;
    gap: 16px;
    align-items: center;
}

.blueprint-box {
    background: var(--surface2);
    border: 2px dashed var(--accent1);
    border-radius: 12px;
    padding: 16px;
    text-align: center;
}

.blueprint-box .box-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    color: var(--accent1);
    letter-spacing: 1px;
    margin-bottom: 8px;
    text-transform: uppercase;
}

.blueprint-box .box-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: #fff;
    margin-bottom: 6px;
}

.blueprint-box .box-attrs {
    font-size: 0.78rem;
    color: var(--text-muted);
    line-height: 1.6;
}

.arrow-connector {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    color: var(--accent1);
}

.arrow-line {
    width: 2px;
    height: 40px;
    background: var(--accent1);
    position: relative;
}

.arrow-line::after {
    content: '▶';
    position: absolute;
    bottom: -14px;
    left: -6px;
    font-size: 12px;
}

.object-box {
    background: var(--surface2);
    border: 1px solid rgba(0, 212, 255, 0.3);
    border-radius: 12px;
    padding: 14px;
    text-align: center;
    transition: all 0.3s;
}

.object-box:hover {
    border-color: var(--accent1);
    transform: scale(1.03);
}

.object-box .obj-label {
    font-size: 0.68rem;
    color: var(--accent1);
    opacity: 0.7;
    letter-spacing: 1px;
    text-transform: uppercase;
    margin-bottom: 4px;
    font-family: 'JetBrains Mono', monospace;
}

.object-box .obj-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: #fff;
    margin-bottom: 4px;
}

.object-box .obj-vals {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Encapsulation diagram */
.encap-diagram {
    display: flex;
    gap: 16px;
    align-items: stretch;
    flex-wrap: wrap;
}

.shield-outer {
    flex: 1;
    min-width: 200px;
    background: var(--surface2);
    border: 1px solid rgba(124, 58, 237, 0.4);
    border-radius: 16px;
    padding: 20px;
    position: relative;
    overflow: hidden;
}

.shield-outer::before {
    content: '🔒';
    position: absolute;
    top: 10px;
    right: 14px;
    font-size: 1.2rem;
    opacity: 0.4;
}

.shield-label {
    font-size: 0.7rem;
    letter-spacing: 1px;
    color: #7c3aed;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
    margin-bottom: 10px;
}

.private-field {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: 8px;
    padding: 8px 12px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.78rem;
    color: #ef4444;
    margin-bottom: 8px;
}

.private-field span {
    color: var(--text-muted);
}

.methods-box {
    flex: 1;
    min-width: 200px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.method-pill {
    background: rgba(124, 58, 237, 0.1);
    border: 1px solid rgba(124, 58, 237, 0.3);
    border-radius: 10px;
    padding: 12px 16px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    color: #a78bfa;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s;
    cursor: default;
}

.method-pill:hover {
    background: rgba(124, 58, 237, 0.2);
    transform: translateX(4px);
}

.method-tag {
    font-size: 0.65rem;
    background: rgba(16, 185, 129, 0.2);
    color: var(--accent3);
    padding: 2px 8px;
    border-radius: 4px;
}

/* Inheritance diagram */
.inherit-diagram {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
}

.parent-class {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.15), rgba(16, 185, 129, 0.05));
    border: 1px solid rgba(16, 185, 129, 0.4);
    border-radius: 14px;
    padding: 16px 28px;
    text-align: center;
    width: fit-content;
    min-width: 220px;
}

.parent-class .cls-type {
    font-size: 0.68rem;
    color: var(--accent3);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
}

.parent-class .cls-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: #fff;
    margin: 4px 0;
}

.parent-class .cls-methods {
    font-size: 0.78rem;
    color: var(--text-muted);
}

.inherit-arrow {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 6px 0;
}

.inherit-line {
    width: 2px;
    height: 30px;
    background: linear-gradient(to bottom, var(--accent3), transparent);
}

.inherit-split {
    display: flex;
    gap: 80px;
    align-items: flex-start;
    position: relative;
}

.inherit-split::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 180px;
    height: 2px;
    background: rgba(16, 185, 129, 0.4);
}

.child-branch {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.child-line {
    width: 2px;
    height: 30px;
    background: rgba(16, 185, 129, 0.4);
}

.child-class {
    background: var(--surface2);
    border: 1px solid rgba(16, 185, 129, 0.3);
    border-radius: 12px;
    padding: 14px 20px;
    text-align: center;
    min-width: 160px;
    transition: all 0.3s;
}

.child-class:hover {
    border-color: var(--accent3);
    transform: translateY(3px);
}

.child-class .cls-type {
    font-size: 0.65rem;
    color: rgba(16, 185, 129, 0.7);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
}

.child-class .cls-name {
    font-size: 0.95rem;
    font-weight: 700;
    color: #fff;
    margin: 3px 0;
}

.child-class .cls-methods {
    font-size: 0.75rem;
    color: var(--accent3);
}

.child-class .inherited {
    font-size: 0.73rem;
    color: var(--text-muted);
    font-style: italic;
}

/* Polymorphism diagram */
.poly-diagram {
    display: flex;
    gap: 14px;
    align-items: flex-end;
    flex-wrap: wrap;
}

.poly-animal {
    flex: 1;
    min-width: 130px;
    background: var(--surface2);
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-radius: 14px;
    padding: 18px;
    text-align: center;
    transition: all 0.3s;
    cursor: default;
}

.poly-animal:hover {
    border-color: var(--accent4);
    transform: translateY(-6px);
}

.poly-emoji {
    font-size: 2.5rem;
    margin-bottom: 8px;
    display: block;
    animation: sway 3s ease-in-out infinite;
}

.poly-animal:nth-child(2) .poly-emoji {
    animation-delay: -1s;
}

.poly-animal:nth-child(3) .poly-emoji {
    animation-delay: -2s;
}

@keyframes sway {

    0%,
    100% {
        transform: rotate(-5deg);
    }

    50% {
        transform: rotate(5deg);
    }
}

.poly-name {
    font-weight: 700;
    color: #fff;
    margin-bottom: 6px;
    font-size: 0.9rem;
}

.poly-method {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: var(--accent4);
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.2);
    border-radius: 6px;
    padding: 6px 10px;
}

.poly-output {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 8px;
}

/* Abstraction diagram */
.abstract-diagram {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.user-side {
    background: var(--surface2);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: 14px;
    padding: 20px;
}

.user-side .side-label {
    font-size: 0.7rem;
    color: var(--accent5);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
    margin-bottom: 12px;
}

.user-sees {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.user-action {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: 8px;
    padding: 10px 14px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    color: #fca5a5;
}

.hidden-side {
    background: var(--surface2);
    border: 1px solid rgba(100, 116, 139, 0.3);
    border-radius: 14px;
    padding: 20px;
    position: relative;
    overflow: hidden;
}

.hidden-side::after {
    content: '';
    position: absolute;
    inset: 0;
    background: repeating-linear-gradient(45deg, transparent, transparent 10px, rgba(0, 0, 0, 0.1) 10px, rgba(0, 0, 0, 0.1) 20px);
    pointer-events: none;
}

.hidden-side .side-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-family: 'JetBrains Mono', monospace;
    margin-bottom: 12px;
}

.hidden-steps {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.hidden-step {
    font-size: 0.78rem;
    color: var(--text-muted);
    padding: 6px 10px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 6px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.hidden-step::before {
    content: '⚙️';
    font-size: 0.7rem;
}

/* Code Block */
.code-block {
    background: #0d1117;
    border: 1px solid var(--border);
    border-radius: 16px;
    overflow: hidden;
    margin-bottom: 8px;
}

.code-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 18px;
    background: rgba(255, 255, 255, 0.03);
    border-bottom: 1px solid var(--border);
}

.code-dots {
    display: flex;
    gap: 6px;
}

.code-dots span {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.dot-r {
    background: #ef4444;
}

.dot-y {
    background: #f59e0b;
}

.dot-g {
    background: #22c55e;
}

.code-lang {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    color: var(--text-muted);
    letter-spacing: 1px;
}

.copy-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border);
    color: var(--text-muted);
    padding: 4px 12px;
    border-radius: 6px;
    font-size: 0.72rem;
    cursor: pointer;
    font-family: 'JetBrains Mono', monospace;
    transition: all 0.2s;
}

.copy-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text);
}

.copy-btn.copied {
    color: var(--accent3);
    border-color: var(--accent3);
}

.code-content {
    padding: 20px 22px;
    overflow-x: auto;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    line-height: 1.75;
    color: #c9d1d9;
    tab-size: 4;
    white-space: pre-wrap;
}

/* Syntax highlighting */
.kw {
    color: #ff7b72;
}

/* keywords */
.cls {
    color: #ffa657;
}

/* class names */
.str {
    color: #a5d6ff;
}

/* strings */
.cmt {
    color: #8b949e;
    font-style: italic;
}

/* comments */
.fn {
    color: #d2a8ff;
}

/* functions */
.num {
    color: #79c0ff;
}

/* numbers */
.op {
    color: #ff7b72;
}

/* operators */
.ann {
    color: #3fb950;
}

/* annotations */
.var {
    color: #e6edf3;
}

.type {
    color: #ffa657;
}

/* Output Box */
.output-box {
    background: #0d1117;
    border: 1px solid rgba(34, 197, 94, 0.2);
    border-radius: 12px;
    padding: 14px 18px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    color: #22c55e;
}

.output-label {
    font-size: 0.65rem;
    letter-spacing: 2px;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.output-label::before {
    content: '▶';
    color: #22c55e;
}

.output-line {
    margin-bottom: 2px;
}

/* Summary section */
.summary-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 36px;
    margin-top: 50px;
    position: relative;
    overflow: hidden;
}

.summary-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.04), rgba(124, 58, 237, 0.04));
}

.summary-title {
    font-family: 'Syne', sans-serif;
    font-size: 1.8rem;
    font-weight: 800;
    color: #fff;
    margin-bottom: 30px;
    text-align: center;
    position: relative;
}

.concept-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
    position: relative;
}

.summary-pill {
    border-radius: 16px;
    padding: 20px;
    text-align: center;
    border: 1px solid var(--border);
    transition: all 0.3s;
    cursor: pointer;
}

.summary-pill:hover {
    transform: translateY(-4px) scale(1.02);
}

.summary-pill .s-icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.summary-pill .s-eng {
    font-family: 'Syne', sans-serif;
    font-weight: 800;
    font-size: 0.95rem;
    color: #fff;
    margin-bottom: 4px;
}

.summary-pill .s-sin {
    font-size: 0.82rem;
    color: var(--text-muted);
}

.s1 {
    background: rgba(0, 212, 255, 0.05);
}

.s1:hover {
    background: rgba(0, 212, 255, 0.1);
    border-color: rgba(0, 212, 255, 0.4);
}

.s2 {
    background: rgba(124, 58, 237, 0.05);
}

.s2:hover {
    background: rgba(124, 58, 237, 0.1);
    border-color: rgba(124, 58, 237, 0.4);
}

.s3 {
    background: rgba(16, 185, 129, 0.05);
}

.s3:hover {
    background: rgba(16, 185, 129, 0.1);
    border-color: rgba(16, 185, 129, 0.4);
}

.s4 {
    background: rgba(245, 158, 11, 0.05);
}

.s4:hover {
    background: rgba(245, 158, 11, 0.1);
    border-color: rgba(245, 158, 11, 0.4);
}

.s5 {
    background: rgba(239, 68, 68, 0.05);
}

.s5:hover {
    background: rgba(239, 68, 68, 0.1);
    border-color: rgba(239, 68, 68, 0.4);
}

/* Scroll reveal */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

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

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

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

/* Mobile */
@media (max-width: 600px) {
    .card-header {
        padding: 22px 20px 18px;
    }

    .card-body {
        padding: 22px 20px;
    }

    .blueprint-diagram {
        grid-template-columns: 1fr;
    }

    .abstract-diagram {
        grid-template-columns: 1fr;
    }

    .inherit-split {
        gap: 30px;
    }

    .summary-section {
        padding: 24px 18px;
    }

    .code-content {
        font-size: 0.76rem;
    }
}