/* concurrengine.com - monochrome geometric specification */

*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    border-radius: 0 !important;
}

html {
    scroll-behavior: smooth;
    background: #FAFAFA;
}

body {
    background: #FAFAFA;
    color: #3A3A3A;
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 1.0625rem;
    line-height: 1.75;
    overflow-x: hidden;
    position: relative;
    min-height: 100vh;
}

::selection {
    background: #0A0A0A;
    color: #FAFAFA;
}

/* Progress track */
.progress-track {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: #C0C0C0;
    z-index: 100;
    cursor: pointer;
    transition: height 200ms cubic-bezier(0.25, 0, 0.1, 1);
}
.progress-track:hover {
    height: 3px;
}
.progress-fill {
    height: 100%;
    width: 0;
    background: #0A0A0A;
    transition: width 80ms linear;
    transform-origin: left center;
}

/* Margin rules */
.margin-rule {
    position: fixed;
    top: 0;
    bottom: 0;
    width: 1px;
    background: #D0D0D0;
    z-index: 5;
    pointer-events: none;
}
.margin-left {
    left: calc(50% - 440px);
}
.margin-right {
    right: calc(50% - 440px);
}

/* Content column */
.content-column {
    width: 100%;
    max-width: 720px;
    margin: 0 auto;
    padding: 0 32px;
    position: relative;
    z-index: 3;
}

/* Sections */
.section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 96px 0;
}

/* Eyebrow / labels */
.eyebrow {
    display: inline-block;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 0.75rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: #909090;
    margin-bottom: 32px;
}

/* Hero */
.section-hero {
    overflow: hidden;
}
.hero-converge {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    pointer-events: none;
}
.hero-line {
    stroke-dasharray: 1600;
    stroke-dashoffset: 1600;
    animation: drawLine 1.6s cubic-bezier(0.25, 0, 0.1, 1) 0.2s forwards;
}
.hero-line-right {
    animation-delay: 0.4s;
}

.hero-column {
    text-align: center;
    position: relative;
    z-index: 3;
}
.hero-eyebrow {
    opacity: 0;
    animation: fadeIn 600ms cubic-bezier(0.25, 0, 0.1, 1) 1.0s forwards;
}
.hero-title {
    font-family: 'Outfit', sans-serif;
    font-weight: 300;
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    letter-spacing: -0.04em;
    line-height: 1.05;
    color: #0A0A0A;
    margin-bottom: 24px;
    opacity: 0;
    animation: fadeIn 600ms cubic-bezier(0.25, 0, 0.1, 1) 1.4s forwards;
}
.hero-title .emph {
    font-weight: 600;
}
.hero-sub {
    font-family: 'Inter', sans-serif;
    font-size: 1.0625rem;
    line-height: 1.75;
    color: #3A3A3A;
    max-width: 520px;
    margin: 0 auto 40px;
    opacity: 0;
    animation: fadeIn 600ms cubic-bezier(0.25, 0, 0.1, 1) 1.8s forwards;
}
.hero-meta {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 0.75rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: #909090;
    opacity: 0;
    animation: fadeIn 600ms cubic-bezier(0.25, 0, 0.1, 1) 2.2s forwards;
}

@keyframes drawLine {
    to { stroke-dashoffset: 0; }
}
@keyframes fadeIn {
    to { opacity: 1; }
}

/* Section titles */
.section-title {
    font-family: 'Outfit', sans-serif;
    font-weight: 300;
    font-size: clamp(2rem, 4vw, 3.25rem);
    letter-spacing: -0.04em;
    line-height: 1.05;
    color: #0A0A0A;
    margin-bottom: 40px;
}
.section-title .emph {
    font-weight: 600;
}

/* Body paragraphs */
.body-paragraph {
    font-family: 'Inter', sans-serif;
    font-size: 1.0625rem;
    line-height: 1.75;
    color: #3A3A3A;
    margin-bottom: 24px;
}
.body-paragraph.subtle {
    color: #909090;
    font-size: 0.95rem;
}

/* Section content reveal */
.section .content-column {
    opacity: 0;
    transition: opacity 300ms cubic-bezier(0.25, 0, 0.1, 1);
}
#hero .content-column {
    opacity: 1;
    transition: none;
}
.section.is-visible .content-column {
    opacity: 1;
}

/* Dividers */
.divider {
    width: 100%;
    max-width: 720px;
    margin: 0 auto;
    padding: 0 32px;
}
.divider svg {
    width: 100%;
    height: auto;
    display: block;
}
.divider .d-line {
    stroke-dasharray: 800;
    stroke-dashoffset: 800;
    transition: stroke-dashoffset 1.2s cubic-bezier(0.25, 0, 0.1, 1);
}
.divider.is-visible .d-line {
    stroke-dashoffset: 0;
}
.divider .d-line:nth-child(1) { transition-delay: 0ms; }
.divider .d-line:nth-child(2) { transition-delay: 80ms; }
.divider .d-line:nth-child(3) { transition-delay: 150ms; }
.divider .d-line:nth-child(4) { transition-delay: 230ms; }
.divider .d-line:nth-child(5) { transition-delay: 300ms; }
.divider .d-line:nth-child(6) { transition-delay: 380ms; }
.divider .d-line:nth-child(7) { transition-delay: 450ms; }
.divider .d-line:nth-child(8) { transition-delay: 530ms; }
.divider .d-line:nth-child(9) { transition-delay: 600ms; }
.divider .d-line:nth-child(10) { transition-delay: 680ms; }

/* Bullet list */
.bullet-list {
    list-style: none;
    margin-top: 16px;
}
.bullet-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    padding: 16px 0;
    border-bottom: 1px solid #F0F0F0;
    color: #3A3A3A;
    transition: color 200ms cubic-bezier(0.25, 0, 0.1, 1);
}
.bullet-item:last-child {
    border-bottom: none;
}
.bullet-mark {
    flex-shrink: 0;
    width: 18px;
    height: 12px;
    margin-top: 8px;
    color: #909090;
    transform-origin: center;
    transition: transform 200ms cubic-bezier(0.25, 0, 0.1, 1), color 200ms cubic-bezier(0.25, 0, 0.1, 1);
}
.bullet-mark svg {
    width: 100%;
    height: 100%;
    overflow: visible;
}
.bullet-item:hover .bullet-mark {
    transform: scale(1.4);
    color: #000000;
}
.bullet-item:hover {
    color: #000000;
}
.bullet-text {
    font-family: 'Inter', sans-serif;
    font-size: 1.0625rem;
    line-height: 1.6;
}

/* Callout */
.callout {
    background: #F0F0F0;
    padding: 28px 32px;
    margin: 32px 0;
    border-left: 1px solid #D0D0D0;
}
.callout-tag {
    display: inline-block;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 0.7rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: #909090;
    margin-bottom: 12px;
}
.callout-code {
    display: block;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 1.05rem;
    color: #0A0A0A;
    letter-spacing: 0.02em;
    margin-bottom: 12px;
}
.callout-note {
    font-family: 'Inter', sans-serif;
    font-size: 0.9rem;
    line-height: 1.65;
    color: #3A3A3A;
}

/* Spec table */
.spec-table {
    margin: 32px 0;
    border-top: 1px solid #D0D0D0;
}
.spec-row {
    display: flex;
    align-items: baseline;
    gap: 16px;
    padding: 18px 0;
    border-bottom: 1px solid #F0F0F0;
    transition: color 200ms cubic-bezier(0.25, 0, 0.1, 1);
}
.spec-row:hover {
    color: #000000;
}
.spec-key {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 0.78rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: #909090;
    flex-shrink: 0;
    width: 220px;
}
.spec-divider-line {
    flex: 1;
    height: 1px;
    background: #F0F0F0;
    transform: translateY(-2px);
}
.spec-value {
    font-family: 'Outfit', sans-serif;
    font-weight: 600;
    font-size: 1rem;
    color: #0A0A0A;
    letter-spacing: -0.01em;
    flex-shrink: 0;
    text-align: right;
}

/* Diagram */
.section-diagram .content-column {
    max-width: 760px;
}
.diagram-frame {
    width: 100%;
    margin: 32px 0;
    background: #FAFAFA;
    border-top: 1px solid #D0D0D0;
    border-bottom: 1px solid #D0D0D0;
    padding: 28px 0;
}
.diagram-svg {
    width: 100%;
    height: auto;
    display: block;
}
.diagram-svg .lane {
    stroke-dasharray: 720;
    stroke-dashoffset: 720;
    transition: stroke-dashoffset 1.4s cubic-bezier(0.25, 0, 0.1, 1);
}
.diagram-frame.is-visible .lane-1 { transition-delay: 0ms; stroke-dashoffset: 0; }
.diagram-frame.is-visible .lane-2 { transition-delay: 200ms; stroke-dashoffset: 0; }
.diagram-frame.is-visible .lane-3 { transition-delay: 400ms; stroke-dashoffset: 0; }
.diagram-frame.is-visible .lane-4 { transition-delay: 600ms; stroke-dashoffset: 0; }
.diagram-frame.is-visible .lane-5 { transition-delay: 800ms; stroke-dashoffset: 0; }
.diagram-frame.is-visible .lane-6 { transition-delay: 1000ms; stroke-dashoffset: 0; }
.diagram-svg .barrier {
    stroke-dasharray: 320;
    stroke-dashoffset: 320;
    transition: stroke-dashoffset 800ms cubic-bezier(0.25, 0, 0.1, 1);
}
.diagram-frame.is-visible .barrier {
    stroke-dashoffset: 0;
}
.diagram-frame.is-visible .barrier:nth-child(1) { transition-delay: 1300ms; }
.diagram-frame.is-visible .barrier:nth-child(2) { transition-delay: 1500ms; }
.diagram-frame.is-visible .barrier:nth-child(3) { transition-delay: 1700ms; }
.diag-label {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 9px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    fill: #909090;
}

/* Closing */
.section-closing {
    min-height: 90vh;
}
.closing-column {
    text-align: center;
}
.closing-converge {
    width: clamp(160px, 30vw, 280px);
    height: auto;
    display: block;
    margin: 0 auto 40px;
}
.closing-converge .hero-line {
    stroke-dasharray: 600;
    stroke-dashoffset: 600;
    transition: stroke-dashoffset 1.4s cubic-bezier(0.25, 0, 0.1, 1);
    animation: none;
}
.section-closing.is-visible .closing-converge .hero-line {
    stroke-dashoffset: 0;
}
.section-closing.is-visible .closing-converge .hero-line:nth-child(2) {
    transition-delay: 200ms;
}
.section-closing.is-visible .closing-converge .hero-line:nth-child(3) {
    transition-delay: 600ms;
}
.closing-line {
    font-family: 'Outfit', sans-serif;
    font-weight: 300;
    font-size: clamp(1.5rem, 2.6vw, 2.25rem);
    letter-spacing: -0.03em;
    line-height: 1.2;
    color: #0A0A0A;
    margin-bottom: 32px;
}
.closing-line .emph {
    font-weight: 600;
}

/* Nav overlay */
.nav-overlay {
    position: fixed;
    inset: 0;
    background: rgba(250, 250, 250, 0.98);
    z-index: 90;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 300ms cubic-bezier(0.25, 0, 0.1, 1);
}
.nav-overlay.is-open {
    opacity: 1;
    pointer-events: auto;
}
.nav-inner {
    width: 100%;
    max-width: 720px;
    padding: 0 32px;
    text-align: left;
}
.nav-eyebrow {
    display: block;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 0.75rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: #909090;
    margin-bottom: 32px;
}
.nav-list {
    list-style: none;
    border-top: 1px solid #D0D0D0;
}
.nav-item {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 22px 0;
    border-bottom: 1px solid #F0F0F0;
    cursor: pointer;
    color: #3A3A3A;
    transition: color 200ms cubic-bezier(0.25, 0, 0.1, 1), transform 200ms cubic-bezier(0.25, 0, 0.1, 1);
    transform-origin: left center;
}
.nav-item:hover {
    color: #000000;
    transform: scale(1.05);
}
.nav-arrow {
    width: 24px;
    height: 16px;
    flex-shrink: 0;
    color: #909090;
    transition: transform 200ms cubic-bezier(0.25, 0, 0.1, 1), color 200ms cubic-bezier(0.25, 0, 0.1, 1);
}
.nav-arrow line {
    stroke: currentColor;
}
.nav-item:hover .nav-arrow {
    transform: scale(1.4);
    color: #000000;
}
.nav-label {
    font-family: 'Outfit', sans-serif;
    font-weight: 300;
    font-size: clamp(1.4rem, 2.4vw, 2rem);
    letter-spacing: -0.02em;
    line-height: 1.2;
}
.nav-close {
    display: inline-block;
    margin-top: 32px;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 500;
    font-size: 0.75rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: #909090;
    cursor: pointer;
    transition: color 200ms cubic-bezier(0.25, 0, 0.1, 1), transform 200ms cubic-bezier(0.25, 0, 0.1, 1);
    transform-origin: left center;
}
.nav-close:hover {
    color: #000000;
    transform: scale(1.05);
}

/* Inline emphasis token */
.emph {
    font-weight: 600;
}

/* Responsive */
@media (max-width: 960px) {
    .margin-rule { display: none; }
    .spec-row {
        flex-wrap: wrap;
        gap: 8px;
    }
    .spec-key {
        width: 100%;
    }
    .spec-divider-line {
        display: none;
    }
    .spec-value {
        text-align: left;
    }
}

@media (max-width: 600px) {
    .content-column { padding: 0 24px; }
    .divider { padding: 0 24px; }
    .section { padding: 80px 0; }
    .callout { padding: 22px 24px; }
    .nav-inner { padding: 0 24px; }
}