/* === Base Reset & Custom Properties === */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --library-cream: #f5f0e8;
    --graphite-slate: #2b2d33;
    --theorem-gold: #c9a84c;
    --edge-copper: #b07442;
    --chalk-dust: #d4cfc5;
    --ink-well: #1a1b1f;
    --proof-blue: #5b7a9e;
}

::selection {
    background: rgba(201, 168, 76, 0.25);
    color: #2b2d33;
}

html {
    scroll-behavior: smooth;
    scrollbar-width: thin;
    scrollbar-color: var(--theorem-gold) var(--chalk-dust);
}

::-webkit-scrollbar {
    width: 6px;
}
::-webkit-scrollbar-track {
    background: var(--chalk-dust);
}
::-webkit-scrollbar-thumb {
    background: var(--theorem-gold);
}

body {
    font-family: 'Source Serif 4', Georgia, serif;
    font-size: clamp(1rem, 1.1vw, 1.15rem);
    font-weight: 400;
    line-height: 1.72;
    letter-spacing: 0.005em;
    color: var(--graphite-slate);
    background: var(--library-cream);
    overflow-x: hidden;
}

/* === Bokeh Background === */
#bokeh-container,
#bokeh-container-dark {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    overflow: hidden;
    z-index: 0;
}

.bokeh-circle {
    position: absolute;
    border-radius: 50%;
    opacity: 0;
    transition: opacity 1.5s ease;
}

.bokeh-circle.visible {
    opacity: 1;
}

/* === Act I — The Theorem === */
.act-theorem {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 4rem 8vw;
    overflow: hidden;
}

.act1-content {
    position: relative;
    z-index: 1;
}

.brand {
    font-family: 'IBM Plex Mono', monospace;
    font-size: clamp(1.2rem, 2vw, 1.8rem);
    font-weight: 600;
    letter-spacing: 0.06em;
    color: var(--graphite-slate);
    margin-bottom: 3rem;
}

.brand span {
    display: inline-block;
    opacity: 0;
    transform: translateY(20px);
}

.brand span.visible {
    opacity: 1;
    transform: translateY(0);
    transition: opacity 0.4s ease, transform 0.4s ease;
}

.headline {
    font-family: 'IBM Plex Mono', monospace;
    font-size: clamp(2rem, 5vw, 4.5rem);
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.15;
    color: var(--graphite-slate);
    max-width: 14ch;
    opacity: 0;
    transform: translateY(15px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

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

.subtitle {
    font-family: 'Source Serif 4', Georgia, serif;
    font-size: clamp(1rem, 1.3vw, 1.25rem);
    color: var(--graphite-slate);
    max-width: 50ch;
    margin-top: 1.5rem;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.8s ease 0.2s, transform 0.8s ease 0.2s;
}

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

.act1-divider {
    position: absolute;
    bottom: 0;
    left: 0;
}

/* === Circuit Trace Dividers === */
.circuit-divider {
    width: 100%;
    height: 20px;
    display: block;
}

.wide-divider {
    background: var(--library-cream);
}

/* === Section Labels === */
.section-label {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 0.8rem;
    font-weight: 400;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--edge-copper);
    margin-bottom: 3rem;
}

/* === Act II — The Proof === */
.act-proof {
    padding: 6rem 8vw;
    position: relative;
}

.lemma-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 3rem;
    max-width: 1100px;
}

@media (max-width: 768px) {
    .lemma-grid {
        grid-template-columns: 1fr;
    }
}

/* === Lemma Cards === */
.lemma-card {
    position: relative;
    opacity: 0;
    transform: translateX(-80px);
    transition: opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1), transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

.lemma-card[data-direction="right"] {
    transform: translateX(80px);
}

.lemma-card.revealed {
    opacity: 1;
    transform: translateX(0);
}

.card-trace {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
}

.trace-path {
    transition: stroke-dashoffset 1.2s ease 0.2s;
}

.lemma-card.revealed .trace-path {
    stroke-dashoffset: 0;
}

.lemma-card.revealed .card-trace circle {
    opacity: 1;
    transition: opacity 0.3s ease 1s;
}

.card-inner {
    padding: 2rem;
    position: relative;
    z-index: 0;
}

.graph-diagram {
    width: 120px;
    height: 120px;
    margin-bottom: 1rem;
    cursor: crosshair;
}

.graph-diagram circle[data-node] {
    transition: fill 0.3s ease;
}

.graph-diagram circle[data-node].active {
    fill: var(--theorem-gold);
}

.graph-diagram circle[data-node].active-blue {
    fill: var(--proof-blue);
}

.card-title {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 1.2rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    color: var(--graphite-slate);
    margin-bottom: 0.5rem;
}

.card-desc {
    font-family: 'Source Serif 4', Georgia, serif;
    color: var(--graphite-slate);
    line-height: 1.65;
    margin-bottom: 1rem;
}

.card-label {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 0.8rem;
    font-weight: 400;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--edge-copper);
}

/* === Act III — The Application (Dark) === */
.act-application {
    position: relative;
    background: var(--ink-well);
    padding: 0;
    min-height: 200vh;
}

.sticky-title {
    position: sticky;
    top: 0;
    z-index: 2;
    font-family: 'IBM Plex Mono', monospace;
    font-size: clamp(2rem, 4vw, 3.5rem);
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--library-cream);
    padding: 4rem 8vw 2rem;
    background: linear-gradient(to bottom, var(--ink-well) 60%, transparent);
}

.dark-cards {
    position: relative;
    z-index: 1;
    padding: 2rem 8vw 6rem;
    display: flex;
    flex-direction: column;
    gap: 3rem;
    max-width: 800px;
}

.dark-card {
    background: rgba(43, 45, 51, 0.8);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    padding: 2.5rem;
    border-left: 2px solid var(--edge-copper);
    opacity: 0;
    transform: translateX(-80px);
    transition: opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1), transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

.dark-card[data-direction="right"] {
    transform: translateX(80px);
}

.dark-card.revealed {
    opacity: 1;
    transform: translateX(0);
}

.dark-card h3 {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--theorem-gold);
    margin-bottom: 0.75rem;
}

.dark-card p {
    font-family: 'Source Serif 4', Georgia, serif;
    color: var(--library-cream);
    line-height: 1.72;
}

/* === Act IV — Q.E.D. === */
.act-qed {
    background: var(--library-cream);
    padding: 8rem 8vw;
    text-align: right;
}

.qed-content {
    max-width: 700px;
    margin-left: auto;
}

.qed-divider {
    margin-bottom: 3rem;
}

.qed-headline {
    font-family: 'IBM Plex Mono', monospace;
    font-size: clamp(2.5rem, 5vw, 5rem);
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--graphite-slate);
    margin-bottom: 1.5rem;
}

.qed-text {
    font-family: 'Source Serif 4', Georgia, serif;
    color: var(--graphite-slate);
    line-height: 1.72;
    margin-bottom: 3rem;
}

.qed-brand {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    color: var(--graphite-slate);
}

.qed-dot {
    color: var(--theorem-gold);
}

/* === Bokeh Keyframes === */
@keyframes drift1 {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(30px, -20px); }
}
@keyframes drift2 {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(-25px, 15px); }
}
@keyframes drift3 {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(15px, 25px); }
}
@keyframes drift4 {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(-20px, -30px); }
}