/* ==========================================================================
   tanso.biz - Muji-Inspired Carbon Measurement Consultancy
   Palette: Ocean-Deep | Layout: Broken-Grid | Tone: Elegant-Sophisticated
   ========================================================================== */

/* --- CSS Custom Properties --- */
:root {
    --abyssal-navy: #0B2434;
    --trench-blue: #0B3D5B;
    --bioluminescent-teal: #2EC4B6;
    --phosphor-aqua: #5DE5D5;
    --bleached-coral: #E8E4DF;
    --drift-gray: #9BAFB8;
    --kelp-shadow: #132F3E;
    --deep-current: #1A5276;
    --thermal-vent: #E07A5F;
    --deepest: #0F1A24;

    --font-headline: 'Cormorant Garamond', 'Georgia', serif;
    --font-body: 'Karla', 'Helvetica Neue', sans-serif;
    --font-mono: 'IBM Plex Mono', 'Courier New', monospace;

    --base-unit: 32px;
    --golden: 1.618;
    --spacing-1: var(--base-unit);                /* 32px */
    --spacing-2: calc(var(--base-unit) * 1.618);  /* ~52px */
    --spacing-3: calc(var(--base-unit) * 2.618);  /* ~84px */
    --spacing-4: calc(var(--base-unit) * 4.236);  /* ~136px */
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-body);
    color: var(--bleached-coral);
    background: linear-gradient(180deg, var(--abyssal-navy) 0%, var(--kelp-shadow) 50%, var(--deepest) 100%);
    background-attachment: fixed;
    overflow-x: hidden;
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Paper texture overlay */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9998;
    opacity: 0.05;
    mix-blend-mode: soft-light;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='256' height='256'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='256' height='256' filter='url(%23n)' opacity='0.5'/%3E%3C/svg%3E");
    background-size: 256px 256px;
}

/* Film grain overlay */
body::after {
    content: '';
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    pointer-events: none;
    z-index: 9999;
    opacity: 0.03;
    background-image:
        radial-gradient(circle at 20% 30%, var(--bleached-coral) 0.5px, transparent 0.5px),
        radial-gradient(circle at 80% 70%, var(--bleached-coral) 0.3px, transparent 0.3px),
        radial-gradient(circle at 50% 10%, var(--bleached-coral) 0.4px, transparent 0.4px),
        radial-gradient(circle at 10% 90%, var(--bleached-coral) 0.5px, transparent 0.5px);
    background-size: 150px 120px, 170px 140px, 130px 160px, 190px 110px;
    animation: grain 0.125s steps(1) infinite;
}

@keyframes grain {
    0% { transform: translate(0, 0); }
    12.5% { transform: translate(-5px, -3px); }
    25% { transform: translate(3px, 5px); }
    37.5% { transform: translate(-3px, 2px); }
    50% { transform: translate(5px, -5px); }
    62.5% { transform: translate(-2px, 4px); }
    75% { transform: translate(4px, -2px); }
    87.5% { transform: translate(-4px, -4px); }
    100% { transform: translate(0, 0); }
}

/* --- Typography --- */
.section-heading {
    font-family: var(--font-headline);
    font-weight: 300;
    font-size: clamp(1.8rem, 5vw + 0.5rem, 4.2rem);
    letter-spacing: 0.06em;
    line-height: 1.2;
    color: var(--bleached-coral);
    margin-bottom: var(--spacing-1);
}

.body-text {
    font-family: var(--font-body);
    font-weight: 400;
    font-size: clamp(0.95rem, 1.2vw + 0.4rem, 1.15rem);
    line-height: 1.75;
    color: var(--bleached-coral);
}

.body-text-large {
    font-size: 1.1rem;
    line-height: 1.85;
}

/* --- Vertical Navigation --- */
#vertical-nav {
    position: fixed;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 12px 0;
}

.nav-item {
    display: flex;
    align-items: center;
    width: 48px;
    height: 48px;
    overflow: hidden;
    white-space: nowrap;
    text-decoration: none;
    color: var(--drift-gray);
    transition: width 400ms cubic-bezier(0.25, 0.46, 0.45, 0.94),
                background-color 300ms ease;
    background: rgba(11, 36, 52, 0.85);
    border-radius: 0 4px 4px 0;
}

.nav-item:hover {
    width: 180px;
    background: rgba(19, 47, 62, 0.95);
}

.nav-item.active {
    background: rgba(26, 82, 118, 0.7);
}

.nav-glyph {
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 48px;
    height: 48px;
    font-family: var(--font-headline);
    font-size: 1.2rem;
    color: var(--bioluminescent-teal);
}

.nav-label {
    font-family: var(--font-mono);
    font-weight: 300;
    font-size: 0.75rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--drift-gray);
    padding-right: 16px;
}

/* --- Depth Markers --- */
#depth-markers {
    position: fixed;
    left: 6px;
    top: 0;
    width: 1px;
    height: 100vh;
    z-index: 500;
    pointer-events: none;
}

.depth-marker {
    position: absolute;
    left: 0;
    width: 1px;
    height: 24px;
    background: var(--phosphor-aqua);
    opacity: 0.4;
    transition: opacity 300ms ease;
}

/* --- Sections Common --- */
.section {
    position: relative;
    min-height: 100vh;
    padding: 0 8vw;
}

/* --- Washi Tape Strips --- */
.washi-strip {
    width: 120px;
    height: 3px;
    background: var(--bioluminescent-teal);
    opacity: 0.35;
    margin-bottom: 24px;
    border-radius: 1px;
    filter: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='t'%3E%3CfeTurbulence baseFrequency='0.04' numOctaves='2' type='turbulence'/%3E%3CfeDisplacementMap in='SourceGraphic' scale='2'/%3E%3C/filter%3E%3C/svg%3E#t");
}

.washi-divider {
    margin-top: var(--spacing-2);
    margin-bottom: var(--spacing-1);
}

/* --- Diagonal Section Dividers --- */
.section::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--trench-blue);
    opacity: 0.3;
    transform: rotate(-2deg);
    transform-origin: left center;
}

.section-hadal::after {
    display: none;
}

/* --- Section 1: Surface (Hero) --- */
.section-surface {
    height: 100vh;
    display: flex;
    align-items: flex-end;
    justify-content: flex-end;
    padding-right: 8vw;
    padding-bottom: 12vh;
    overflow: hidden;
}

.enso {
    position: absolute;
    pointer-events: none;
}

.enso-1 {
    top: 8vh;
    left: -40px;
    transform: rotate(5deg);
    opacity: 0.4;
}

.surface-content {
    text-align: right;
    z-index: 10;
}

.surface-tagline {
    font-family: var(--font-mono);
    font-weight: 300;
    font-size: 0.75rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--drift-gray);
    margin-bottom: 16px;
}

.surface-title {
    font-family: var(--font-headline);
    font-weight: 300;
    font-size: clamp(3rem, 8vw, 5rem);
    letter-spacing: 0.06em;
    color: var(--bleached-coral);
    line-height: 1.1;
}

.scroll-indicator {
    position: absolute;
    bottom: 3vh;
    left: 50%;
    transform: translateX(-50%);
    z-index: 10;
}

.scroll-arrow {
    width: 12px;
    height: 12px;
    border-right: 1.5px solid var(--phosphor-aqua);
    border-bottom: 1.5px solid var(--phosphor-aqua);
    transform: rotate(45deg);
    opacity: 0.6;
    animation: pulse-arrow 2.4s ease-in-out infinite;
}

@keyframes pulse-arrow {
    0%, 100% {
        opacity: 0.3;
        transform: rotate(45deg) translateY(0);
    }
    50% {
        opacity: 0.8;
        transform: rotate(45deg) translateY(8px);
    }
}

/* --- Section 2: Thermocline --- */
.section-thermocline {
    padding-top: var(--spacing-4);
    padding-bottom: var(--spacing-4);
    min-height: 150vh;
}

.hex-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    opacity: 0.08;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='80' height='92'%3E%3Cpath d='M40 0 L73 18 L73 54 L40 72 L7 54 L7 18 Z' fill='none' stroke='%232EC4B6' stroke-width='0.5' opacity='0.4'/%3E%3Cpath d='M40 20 L53 28 L53 44 L40 52 L27 44 L27 28 Z' fill='none' stroke='%232EC4B6' stroke-width='0.3' opacity='0.3'/%3E%3Ccircle cx='40' cy='0' r='1.5' fill='%232EC4B6' opacity='0.3'/%3E%3C/svg%3E");
    background-size: 80px 92px;
}

.thermocline-grid {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
}

.content-block {
    background: var(--kelp-shadow);
    padding: var(--spacing-1);
    position: relative;
    margin-bottom: var(--spacing-1);
}

.block-1 {
    margin-left: -3vw;
    z-index: 3;
}

.block-2 {
    margin-top: -40px;
    margin-left: 2vw;
    z-index: 2;
}

.block-3 {
    margin-top: -40px;
    margin-left: -5vw;
    z-index: 1;
}

/* --- Section 3: Mesopelagic (Philosophy) --- */
.section-mesopelagic {
    padding-top: var(--spacing-4);
    padding-bottom: var(--spacing-4);
    min-height: 150vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.enso-2 {
    right: -60px;
    top: 50%;
    transform: translateY(-50%) rotate(10deg);
    opacity: 0.2;
}

.philosophy-column {
    max-width: 680px;
    margin: 0 auto;
    position: relative;
    z-index: 10;
}

/* --- Section 4: Abyssal (Services) --- */
.section-abyssal {
    padding-top: var(--spacing-4);
    padding-bottom: var(--spacing-4);
    min-height: 150vh;
    background: linear-gradient(180deg, transparent 0%, rgba(15, 26, 36, 0.5) 100%);
}

.abyssal-grid {
    max-width: 1000px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2);
}

.service-card {
    background: var(--kelp-shadow);
    padding: var(--spacing-1);
    border-left: 3px solid var(--bioluminescent-teal);
    transition: transform 300ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
    position: relative;
}

.service-card:hover {
    transform: scale(1.03);
}

.card-mon {
    margin-bottom: 16px;
    opacity: 0.8;
}

.card-title {
    font-family: var(--font-headline);
    font-weight: 300;
    font-size: clamp(1.2rem, 2vw + 0.3rem, 1.8rem);
    letter-spacing: 0.06em;
    color: var(--bleached-coral);
    margin-bottom: 12px;
}

.card-text {
    font-family: var(--font-body);
    font-weight: 400;
    font-size: clamp(0.85rem, 1vw + 0.3rem, 1rem);
    line-height: 1.7;
    color: var(--drift-gray);
}

/* --- Section 5: Hadal (Closing) --- */
.section-hadal {
    padding-top: var(--spacing-4);
    padding-bottom: var(--spacing-3);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: var(--deepest);
}

.enso-3 {
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%) rotate(15deg);
    opacity: 0.15;
}

.hadal-content {
    position: relative;
    z-index: 10;
}

.hadal-statement {
    font-family: var(--font-headline);
    font-weight: 300;
    font-size: clamp(2rem, 6vw, 3.5rem);
    letter-spacing: 0.06em;
    color: var(--bleached-coral);
    max-width: 800px;
    margin: 0 auto var(--spacing-3);
    line-height: 1.3;
}

.hadal-contact {
    margin-top: var(--spacing-2);
}

.contact-line {
    font-family: var(--font-mono);
    font-weight: 300;
    font-size: 0.75rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--drift-gray);
    margin-bottom: 8px;
}

/* --- Reveal Animations --- */
.reveal-block {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 600ms ease, transform 600ms ease;
}

.reveal-block.revealed {
    opacity: 1;
    transform: translateY(0);
}

/* --- Scale-Hover Pattern --- */
a, .service-card, .nav-item {
    transition: transform 300ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

a:hover {
    transform: scale(1.03);
}

/* --- Responsive --- */
@media (max-width: 768px) {
    #vertical-nav {
        display: none;
    }

    .section {
        padding: 0 6vw;
    }

    .abyssal-grid {
        grid-template-columns: 1fr;
    }

    .block-1, .block-2, .block-3 {
        margin-left: 0;
    }

    .enso-1 {
        top: 4vh;
        left: -80px;
    }

    .enso-2 {
        right: -100px;
    }
}

@media (max-width: 480px) {
    .surface-title {
        font-size: clamp(2.2rem, 10vw, 3.5rem);
    }

    .hadal-statement {
        font-size: clamp(1.6rem, 5vw, 2.5rem);
    }

    .section {
        padding: 0 5vw;
    }
}