/* ==========================================================================
   DEPTH & SCROLL-DRAWN CURVES (home page)
   Hero architecture stack, request-path spine, experience rail fill,
   and perspective transforms on cards. Driven by js/depth.js.
   ========================================================================== */

/* ── Hero: isometric architecture stack ── */
.stack {
    position: relative;
    height: 440px;
    display: grid;
    place-items: center;
    perspective: 1600px;
}

.stack__scene {
    --gap: 64px;
    --tilt-x: 0deg;
    --tilt-z: 0deg;
    position: relative;
    width: 290px;
    height: 290px;
    transform-style: preserve-3d;
    transform: translateY(calc(var(--gap) * 1.2)) rotateX(calc(58deg + var(--tilt-x))) rotateZ(calc(-42deg + var(--tilt-z)));
}

.stack__layer {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column-reverse;
    gap: 14px;
    padding: 20px;
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--border-hover);
    box-shadow: 0 40px 50px -30px rgba(20, 23, 28, 0.35);
    transform: translateZ(calc(var(--i) * var(--gap)));
}

.stack__layer--bus {
    background: rgba(239, 243, 253, 0.94);
    border-color: var(--accent-muted);
}

.stack__label {
    font: 500 11px/1 var(--font-mono);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--muted);
}

.stack__layer--bus .stack__label {
    color: var(--accent);
}

.stack__row {
    flex: 1;
    display: flex;
    gap: 10px;
}

.stack__node {
    flex: 1;
    border-radius: 10px;
    border: 1px solid var(--border-hover);
    background:
        linear-gradient(var(--border) 0 0) 12px 14px / 40% 3px no-repeat,
        linear-gradient(var(--border) 0 0) 12px 24px / 25% 3px no-repeat,
        var(--bg);
}

.stack__node--wide {
    flex: 2;
}

.stack__node--db {
    border-radius: 50% / 22%;
    border-color: var(--accent-muted);
}

.stack__partitions {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.stack__partitions span {
    height: 12px;
    border-radius: 3px;
    background: repeating-linear-gradient(90deg, var(--accent-muted) 0 16px, transparent 16px 20px);
    background-size: 20px 100%;
    animation: stack-append 2.4s linear infinite;
}

.stack__partitions span:nth-child(2) { animation-duration: 3.1s; }
.stack__partitions span:nth-child(3) { animation-duration: 2.7s; }
.stack__partitions span:nth-child(4) { animation-duration: 3.6s; }

@keyframes stack-append {
    to { background-position: 20px 0; }
}

/* A wire hangs from the top layer to storage; a request travels down it. */
.stack__wire {
    position: absolute;
    left: var(--x);
    top: var(--y);
    width: 2px;
    height: calc(var(--gap) * 3);
    transform-origin: top center;
    transform: translateZ(calc(var(--gap) * 3)) rotateX(-90deg);
    background: repeating-linear-gradient(var(--accent-muted) 0 4px, transparent 4px 8px);
}

.stack__wire i {
    position: absolute;
    left: -3px;
    top: 0;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light);
    animation: stack-request 3.3s cubic-bezier(0.45, 0, 0.55, 1) var(--d) infinite;
}

@keyframes stack-request {
    0% { top: 0; opacity: 0; }
    10% { opacity: 1; }
    90% { opacity: 1; }
    100% { top: 100%; opacity: 0; }
}

/* ── Three.js version of the stack (js/stack3d.js) ── */
.stack__canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: none;
}

.stack.is-3d .stack__canvas {
    display: block;
}

.stack.is-3d .stack__scene {
    display: none;
}

.stack__tags {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.stack__tag {
    position: absolute;
    top: 0.5rem;
    left: 0;
    display: flex;
    flex-direction: column;
    gap: 3px;
    padding-left: 14px;
    width: 220px;
    opacity: 0;
    transform: translateY(4px);
    transition: opacity 0.35s ease, transform 0.35s ease;
}

.stack__tag::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.45rem;
    width: 8px;
    height: 1px;
    background: var(--accent);
}

.stack__tag.is-active {
    opacity: 1;
    transform: none;
}

.stack__tag-name {
    font: 500 11px/1.2 var(--font-mono);
    letter-spacing: 0.04em;
    text-transform: uppercase;
    color: var(--muted);
    transition: color 0.3s ease;
}

.stack__tag-metric {
    font: 500 13px/1.3 var(--font-sans);
    color: var(--accent);
}

.stack__tag.is-active .stack__tag-name {
    color: var(--text-heading);
}

/* ── Request-path spine drawn as you scroll ── */
.has-depth .main {
    position: relative;
}

.has-depth .main > section {
    position: relative;
    z-index: 1;
}

.spine {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: visible;
    pointer-events: none;
    z-index: 0;
}

.spine__track {
    fill: none;
    stroke: var(--border-hover);
    stroke-width: 1.5;
    stroke-dasharray: 2 6;
    stroke-linecap: round;
}

.spine__path {
    fill: none;
    stroke: var(--accent);
    stroke-width: 2;
    stroke-linecap: round;
}

.spine__node {
    fill: var(--bg);
    stroke: var(--border-hover);
    stroke-width: 1.5;
    transition: fill 0.3s ease, stroke 0.3s ease;
}

.spine__node.is-reached {
    fill: var(--accent);
    stroke: var(--accent);
}

.spine__label {
    font: 500 11px var(--font-mono);
    letter-spacing: 0.04em;
    fill: var(--subtle);
    transition: fill 0.3s ease;
}

.spine__label.is-reached {
    fill: var(--text-heading);
}

.spine__head {
    fill: var(--accent);
}

.spine__halo {
    fill: var(--accent);
    opacity: 0.15;
}

.spine-compact .main {
    padding-left: 2.6rem;
}

/* ── Experience: the rail fills role by role ── */
.has-depth .journey__list::after {
    content: '';
    position: absolute;
    left: 139px;
    top: 8px;
    width: 2px;
    height: calc((100% - 16px) * var(--fill, 0));
    background: var(--accent);
    border-radius: 2px;
}

.has-depth .journey-item__content::before {
    background: var(--bg);
    border: 2px solid var(--border-hover);
    box-shadow: none;
    transition: background 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.has-depth .journey-item.is-reached .journey-item__content::before {
    background: var(--accent);
    border-color: var(--accent);
    box-shadow: 0 0 0 4px var(--accent-light);
}

/* ── Cards and panels get perspective from depth.js ── */
.has-depth .journey-item,
.has-depth .about__copy,
.has-depth .about__aside,
.has-depth .expertise,
.has-depth .contact__panel {
    transform-origin: 50% 100%;
    will-change: transform;
}

.about__portrait {
    margin: 0 0 1.25rem;
    border-radius: var(--radius-md);
    overflow: hidden;
    aspect-ratio: 4 / 5;
    max-height: 340px;
}

.about__portrait img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: 50% 30%;
}

.has-depth .main > section + section {
    margin-top: 12vh;
}

@media (max-width: 900px) {
    .hero__visual {
        order: 0;
        max-width: none;
        margin: 0;
    }

    .stack {
        height: 400px;
    }

    .stack__tag {
        top: auto;
        bottom: 0;
    }

    .stack__scene {
        --gap: 50px;
        width: 220px;
        height: 220px;
    }

    .stack__layer {
        padding: 14px;
        gap: 10px;
    }

    .stack__label {
        font-size: 9px;
    }

    .has-depth .main > section + section {
        margin-top: 8vh;
    }
}

@media (max-width: 640px) {
    .has-depth .journey__list::after {
        left: 5px;
        top: 6px;
        height: calc((100% - 12px) * var(--fill, 0));
    }

    .has-depth .journey-item::before {
        background: var(--bg);
        border: 2px solid var(--border-hover);
        box-shadow: none;
        transition: background 0.3s ease, border-color 0.3s ease;
    }

    .has-depth .journey-item.is-reached::before {
        background: var(--accent);
        border-color: var(--accent);
        box-shadow: 0 0 0 4px var(--accent-light);
    }
}

@media (prefers-reduced-motion: reduce) {
    .stack__partitions span,
    .stack__wire i {
        animation: none;
    }
}