/* ============================================================
   gunsul.studio — Concrete Construction Archive
   Palette: Pure monochrome (#000000 to #FFFFFF)
   Fonts: Bebas Neue, Inter, IBM Plex Mono
   Layout: Fixed 720px single column on black void
   No gradients. No transparency. No box-shadows. No blur.
   Every color boundary is a hard edge.
   ============================================================ */

/* --- RESET & BASE --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: auto;
    overflow-x: hidden;
}

body {
    background: #000000;
    color: #1A1A1A;
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 16px;
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* --- BACKGROUND GRID LINES ---
   Thin 1px lines at 120px vertical intervals across entire viewport.
   Independent coordinate system -- does not align with content.
   Opacity 0.15 on light backgrounds, pulses to 0.30 on scroll stop. */
#grid-lines-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
    background-image: repeating-linear-gradient(
        to bottom,
        transparent,
        transparent 119px,
        #B0B0B0 119px,
        #B0B0B0 120px
    );
    opacity: 0.15;
    transition: opacity 800ms ease;
}

#grid-lines-overlay.pulse {
    opacity: 0.30;
}

#grid-lines-overlay.dimmed {
    opacity: 0.08;
}

/* --- INTRO SCREEN ---
   Pure black screen. Line draws left-to-right.
   Titles appear instantly (no fade). Then screen scrolls away. */
#intro-screen {
    position: relative;
    width: 100%;
    height: 100vh;
    background: #000000;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
}

#intro-line {
    width: 100%;
    height: 1px;
    background: #FFFFFF;
    transform: scaleX(0);
    transform-origin: left;
    position: absolute;
    top: 50%;
    left: 0;
}

#intro-line.animate {
    animation: drawLine 1200ms cubic-bezier(0.25, 0.0, 0.0, 1.0) forwards;
}

@keyframes drawLine {
    from { transform: scaleX(0); }
    to { transform: scaleX(1); }
}

#intro-title-top,
#intro-title-bottom {
    font-family: 'Bebas Neue', sans-serif;
    font-weight: 400;
    color: #FFFFFF;
    letter-spacing: 0.12em;
    line-height: 0.95;
    font-size: clamp(5rem, 18vw, 14rem);
    text-align: center;
    opacity: 0;
    position: absolute;
    width: 100%;
}

#intro-title-top {
    bottom: 50%;
    margin-bottom: 4px;
}

#intro-title-bottom {
    top: 50%;
    margin-top: 4px;
}

#intro-title-top.visible,
#intro-title-bottom.visible {
    opacity: 1;
}

/* --- CONTENT COLUMN ---
   Exactly 720px wide -- a concrete pillar.
   Flanked by pure black gutters to viewport edges.
   On narrow screens, 16px side margins. */
#content-column {
    width: 720px;
    max-width: calc(100% - 32px);
    margin: 0 auto;
    padding: 0 0 200px 0;
    position: relative;
    z-index: 2;
    background: #F5F5F5;
    transition: background-color 600ms ease;
}

@media (max-width: 752px) {
    #content-column {
        width: auto;
        margin: 0 16px;
    }
}

/* --- FORMWORK SEAM LINES ---
   Vertical lines at golden ratio subdivisions (38.2%, 61.8%).
   1px #D0D0D0 running full height of text blocks. */
.formwork-seams {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

.formwork-seams::before,
.formwork-seams::after {
    content: '';
    position: absolute;
    top: 0;
    height: 100%;
    width: 1px;
    background: #D0D0D0;
    opacity: 0.12;
}

.formwork-seams::before {
    left: 38.2%;
}

.formwork-seams::after {
    left: 61.8%;
}

/* --- CONTENT BLOCKS ---
   Discrete rectangular units.
   Entry animation: translateY(24px) + opacity:0 -> final position.
   400ms cubic-bezier(0.25, 0.0, 0.0, 1.0) -- gravitational settle. */
.content-block {
    position: relative;
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 400ms cubic-bezier(0.25, 0.0, 0.0, 1.0),
                transform 400ms cubic-bezier(0.25, 0.0, 0.0, 1.0);
}

.content-block.visible {
    opacity: 1;
    transform: translateY(0) translateX(0);
}

/* Every third block offsets 48px left -- staggered precast panels. */
.offset-block {
    margin-left: -48px;
    transform: translateX(-48px);
}

.offset-block.visible {
    margin-left: -48px;
    transform: translateY(0) translateX(0);
}

@media (max-width: 752px) {
    .offset-block {
        margin-left: -24px;
        transform: translateX(-24px);
    }

    .offset-block.visible {
        margin-left: -24px;
        transform: translateY(0) translateX(0);
    }
}

/* --- BLOCK NUMBER STAMPS ---
   IBM Plex Mono 11px, #B0B0B0. Sequential: 001, 002, 003.
   Like panel numbers stamped on precast concrete. */
.block-number {
    font-family: 'IBM Plex Mono', monospace;
    font-weight: 400;
    font-size: 11px;
    color: #B0B0B0;
    letter-spacing: 0.05em;
    padding: 12px 0 4px 0;
    position: relative;
    z-index: 1;
}

.void-number {
    color: #666666;
}

/* --- METADATA STRIPS ---
   IBM Plex Mono, data stamps on engineering drawings.
   Dates, material specs, structural dimensions. */
.metadata-strip {
    font-family: 'IBM Plex Mono', monospace;
    font-weight: 400;
    font-size: 14px;
    color: #808080;
    letter-spacing: 0.05em;
    padding: 0 0 24px 0;
    position: relative;
    z-index: 1;
}

.meta-sep {
    margin: 0 8px;
    color: #B0B0B0;
}

.meta-spec {
    color: #666666;
}

/* --- TEXT BLOCKS ---
   Left-aligned text on #F5F5F5 (fresh poured concrete). */
.text-block {
    background: #F5F5F5;
    padding: 0 24px 48px 24px;
    position: relative;
}

.block-heading {
    font-family: 'Bebas Neue', sans-serif;
    font-weight: 400;
    font-size: clamp(3rem, 9vw, 7rem);
    letter-spacing: 0.12em;
    line-height: 0.95;
    color: #1A1A1A;
    margin-bottom: 24px;
    position: relative;
    z-index: 1;
}

.block-body {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 16px;
    line-height: 1.7;
    color: #1A1A1A;
    margin-bottom: 24px;
    position: relative;
    z-index: 1;
}

.block-body:last-child {
    margin-bottom: 0;
}

/* Emphasis: weight 600 or UPPERCASE only. Never italic, never color. */
.block-body strong {
    font-weight: 600;
    font-style: normal;
}

/* --- PHOTO BLOCKS ---
   Full-column-width photograph. No padding, no border-radius, no caption overlay.
   Revealed by horizontal wipe: concrete gray overlay contracts left-to-right. */
.photo-block {
    background: #F5F5F5;
    padding: 0;
}

.photo-block .block-number,
.photo-block .metadata-strip {
    padding-left: 24px;
    padding-right: 24px;
}

.photo-container {
    position: relative;
    overflow: hidden;
    width: 100%;
}

.photo-wipe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #B0B0B0;
    z-index: 5;
    clip-path: inset(0 0 0 0);
    transition: clip-path 800ms cubic-bezier(0.25, 0.0, 0.0, 1.0);
}

.photo-container.revealed .photo-wipe {
    clip-path: inset(0 0 0 100%);
}

.photo-surface {
    display: block;
    width: 100%;
}

/* --- VOID BLOCKS ---
   100vh of pure black with a single centered line of Bebas Neue white text.
   Structural pauses -- like crossing an empty floor in a parking garage.
   Text appears 300ms after background transition completes. */
.void-block {
    background: #000000;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    position: relative;
    padding: 24px;
}

.void-block .block-number {
    position: absolute;
    top: 12px;
    left: 24px;
    color: #666666;
}

.void-text {
    font-family: 'Bebas Neue', sans-serif;
    font-weight: 400;
    font-size: clamp(2rem, 6vw, 4rem);
    color: #FFFFFF;
    letter-spacing: 0.12em;
    line-height: 0.95;
    text-align: center;
    opacity: 0;
    transition: opacity 300ms ease;
    transition-delay: 300ms;
}

.void-block.visible .void-text {
    opacity: 1;
}

/* Void block on dark backgrounds -- text uses #E0E0E0 for body if needed */
.void-block .block-body {
    color: #E0E0E0;
}

/* --- BLOCK RULES ---
   2px horizontal dividers in #B0B0B0 (concrete gray).
   Extend exactly to column edges, never beyond. */
.block-rule {
    border: none;
    height: 2px;
    background: #B0B0B0;
    width: 100%;
    margin: 0;
}

/* --- VOID BLOCK LAYOUT OVERRIDES --- */
.content-block.void-block {
    margin-left: 0;
    margin-right: 0;
}

.void-block.offset-block {
    margin-left: -48px;
}

@media (max-width: 752px) {
    .void-block.offset-block {
        margin-left: -24px;
    }
}

/* --- BLOCK COUNTER ---
   Fixed bottom-right. IBM Plex Mono 11px, #666666.
   tabular-nums prevents layout shift.
   The only persistent UI element -- page number on engineering drawing. */
#block-counter {
    position: fixed;
    bottom: 24px;
    right: 24px;
    font-family: 'IBM Plex Mono', monospace;
    font-weight: 400;
    font-size: 11px;
    color: #666666;
    letter-spacing: 0.05em;
    z-index: 100;
    font-variant-numeric: tabular-nums;
    opacity: 0;
    transition: opacity 400ms ease;
}

#block-counter.active {
    opacity: 1;
}

.counter-sep {
    margin: 0 4px;
    color: #808080;
}

/* --- SCROLLBAR ---
   Minimal, monochrome. */
::-webkit-scrollbar {
    width: 4px;
}

::-webkit-scrollbar-track {
    background: #000000;
}

::-webkit-scrollbar-thumb {
    background: #333333;
}

::-webkit-scrollbar-thumb:hover {
    background: #666666;
}

/* --- SELECTION ---
   Dark charcoal background, white text. */
::selection {
    background: #333333;
    color: #FFFFFF;
}

/* --- HOVER STATE ---
   Interactive elements use #333333 on light backgrounds. */
a {
    color: #1A1A1A;
    text-decoration: none;
    transition: color 200ms ease;
}

a:hover {
    color: #333333;
}