/* tanso.biz — Gold-on-black carbon sketchbook aesthetic */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --gold-primary: #c9a84c;
    --gold-dark: #8a7a4a;
    --gold-light: #e8d48b;
    --parchment: #d4c9a8;
    --black: #0a0a0a;
    --black-deep: #141410;
    --warm-gray: #7a7060;
    --forest-green: #3a5a3a;
}

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--black);
    color: var(--gold-primary);
    font-family: 'DM Sans', sans-serif;
    font-weight: 400;
    overflow-x: hidden;
}

/* Scroll Thread */
.scroll-thread {
    position: fixed;
    right: 24px;
    top: 0;
    bottom: 0;
    width: 1px;
    background: rgba(201, 168, 76, 0.15);
    z-index: 100;
}

.scroll-thread-progress {
    position: absolute;
    top: 0;
    left: 0;
    width: 1px;
    height: 0%;
    background: var(--gold-primary);
    transition: height 0.1s linear;
}

.thread-marker {
    position: absolute;
    left: -4px;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    border: 1px solid var(--gold-primary);
    background: transparent;
    opacity: 0.4;
    transition: opacity 0.5s ease, background 0.5s ease;
}

.thread-marker:nth-child(2) { top: 10%; }
.thread-marker:nth-child(3) { top: 30%; }
.thread-marker:nth-child(4) { top: 50%; }
.thread-marker:nth-child(5) { top: 70%; }
.thread-marker:nth-child(6) { top: 90%; }

.thread-marker.active {
    opacity: 1;
    background: var(--gold-primary);
}

/* Spreads */
.spread {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 4rem 2rem;
}

.spread-content {
    max-width: 800px;
    width: 100%;
    text-align: center;
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 1.2s ease, transform 1.2s ease;
}

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

/* Typography */
.display-title {
    font-family: 'Josefin Sans', sans-serif;
    font-weight: 300;
    font-size: clamp(2.8rem, 6vw, 6rem);
    line-height: 1.05;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--gold-light);
    margin-bottom: 1rem;
}

.section-heading {
    font-family: 'Josefin Sans', sans-serif;
    font-weight: 300;
    font-size: clamp(2rem, 4.5vw, 4.5rem);
    line-height: 1.1;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--gold-primary);
    margin-bottom: 1.5rem;
}

.body-text {
    font-family: 'DM Sans', sans-serif;
    font-weight: 400;
    font-size: clamp(0.95rem, 1.2vw, 1.15rem);
    line-height: 1.7;
    color: var(--warm-gray);
    max-width: 520px;
    margin: 0 auto 1.5rem;
}

.annotation {
    display: block;
    color: var(--gold-dark);
    font-size: clamp(1rem, 1.5vw, 1.4rem);
    margin-top: 0.5rem;
}

.caveat {
    font-family: 'Caveat', cursive;
    font-weight: 400;
}

/* Botanicals */
.botanical {
    display: block;
    margin: 2rem auto;
    max-width: 280px;
    height: auto;
}

.botanical-hero {
    max-width: 180px;
    max-height: 50vh;
}

.botanical-network {
    max-width: 200px;
}

.botanical-branch {
    max-width: 400px;
}

.botanical-seed {
    max-width: 80px;
}

/* Sketch line animation */
.sketch-line {
    stroke-dasharray: 1000;
    stroke-dashoffset: 1000;
    transition: stroke-dashoffset 2.5s ease;
}

.visible .sketch-line {
    stroke-dashoffset: 0;
}

/* Process annotations */
.process-annotations {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.process-annotations .annotation {
    font-size: clamp(1.1rem, 1.8vw, 1.6rem);
    color: var(--warm-gray);
}

/* Particle canvas */
#particle-canvas {
    display: block;
    margin: 2rem auto;
    width: 300px;
    height: 300px;
    opacity: 0.7;
}

/* Spread backgrounds */
.spread-1 {
    background: radial-gradient(ellipse at center, var(--black-deep) 0%, var(--black) 100%);
}

.spread-2, .spread-3, .spread-4, .spread-5 {
    background: var(--black);
}

/* Subtle grain texture via CSS */
.spread::before {
    content: '';
    position: absolute;
    inset: 0;
    opacity: 0.03;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
    pointer-events: none;
}

/* Responsive */
@media (max-width: 600px) {
    .scroll-thread {
        right: 12px;
    }
    .spread {
        padding: 3rem 1.5rem;
    }
}