/* ============================================================
   Youngsoon Seo — Portfolio
   Case-study layout system. Shared across every case study so
   they all read with the same editorial rhythm as the home page.
   ============================================================ */

:root { --cs-read: 720px; --cs-gut: clamp(24px, 5vw, 40px); }

.back-row { padding-top: 40px; }
.back-link {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 15px; color: var(--gray);
}
.back-link .ar { transition: transform .3s cubic-bezier(.2,.7,.2,1); }
.back-link:hover { color: var(--ink); }
.back-link:hover .ar { transform: translateX(-4px); }

/* ---------- hero ---------- */
.cs-hero { padding-block: 56px 8px; }
.cs-eyebrow {
  font-size: 14px; letter-spacing: 0.04em; text-transform: uppercase;
  color: var(--gray-soft); margin: 0 0 24px;
}
.cs-hero h1 {
  margin: 0;
  max-width: 920px;
  font-size: clamp(34px, 5.2vw, 60px);
  line-height: 1.1;
  letter-spacing: -0.025em;
  font-weight: 500;
  color: var(--ink-strong);
  text-wrap: balance;
}

.cs-hero-figure { margin-top: 40px; }
.cs-hero-figure img {
  width: 100%; display: block; border-radius: 8px;
  background: #f4f5f7;
  border: 1px solid var(--line-soft);
  box-shadow: 0 24px 60px -32px rgba(0,0,0,.3);
}

/* ---------- facts + intro ---------- */
.cs-facts {
  margin-top: 56px;
  display: grid;
  grid-template-columns: repeat(3, auto);
  gap: 64px;
  justify-content: start;
  padding-bottom: 48px;
  border-bottom: 1px solid var(--line-soft);
}
.cs-facts dt { font-size: 13px; letter-spacing: 0.06em; text-transform: uppercase; color: var(--gray-soft); margin-bottom: 8px; }
.cs-facts dd { margin: 0; font-size: 17px; color: var(--ink-strong); letter-spacing: -0.01em; }

.cs-intro {
  margin-top: 48px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
}
.cs-intro h2 { margin: 0 0 16px; font-size: 20px; font-weight: 500; letter-spacing: -0.02em; color: var(--ink-strong); }
.cs-intro p { margin: 0; font-size: 16px; line-height: 1.7; color: var(--gray); text-wrap: pretty; }

/* ---------- reading sections ---------- */
.cs-section { width: min(var(--cs-read), 100% - 2 * var(--cs-gut)); margin-inline: auto; padding-top: 96px; }
.cs-section.tight { padding-top: 48px; }
.cs-section h2 {
  margin: 0 0 24px; font-size: 24px; font-weight: 600;
  letter-spacing: -0.02em; color: var(--ink-strong);
}
.cs-section h3 {
  margin: 0 0 16px; font-size: 20px; font-weight: 500;
  letter-spacing: -0.02em; color: var(--ink-strong);
}
.cs-section p { margin: 0 0 18px; font-size: 16px; line-height: 1.75; color: var(--gray); text-wrap: pretty; }
.cs-section p:last-child { margin-bottom: 0; }
.cs-section p strong { color: var(--ink-strong); font-weight: 500; }
.cs-lead { font-size: 18px !important; line-height: 1.6 !important; color: var(--ink-strong) !important; }

.cs-list { margin: 0 0 18px; padding: 0; list-style: none; }
.cs-list li {
  position: relative; padding-left: 22px; margin-bottom: 12px;
  font-size: 16px; line-height: 1.7; color: var(--gray);
}
.cs-list li::before {
  content: ""; position: absolute; left: 2px; top: 12px;
  width: 5px; height: 5px; border-radius: 50%; background: var(--gray-soft);
}
.cs-list li strong { color: var(--ink-strong); font-weight: 500; }

/* labeled steps / process items */
.cs-steps { margin: 8px 0 0; padding: 0; list-style: none; counter-reset: step; }
.cs-steps li {
  padding: 24px 0; border-top: 1px solid var(--line-soft);
  display: grid; grid-template-columns: 40px 1fr; gap: 20px;
}
.cs-steps li:last-child { border-bottom: 1px solid var(--line-soft); }
.cs-steps .num { counter-increment: step; font-size: 15px; color: var(--gray-soft); padding-top: 2px; }
.cs-steps .num::before { content: counter(step, decimal-leading-zero); }
.cs-steps .st-title { font-size: 17px; color: var(--ink-strong); letter-spacing: -0.01em; margin: 0 0 6px; font-weight: 500; }
.cs-steps .st-desc { font-size: 16px; line-height: 1.65; color: var(--gray); margin: 0; }
.cs-steps .st-desc + .st-desc { margin-top: 10px; }

.hmw {
  margin: 26px 0; padding: 24px 28px;
  background: var(--placeholder); border-radius: 4px;
  font-size: 19px; line-height: 1.5; letter-spacing: -0.015em;
  color: var(--ink-strong); text-wrap: pretty;
}
.hmw .q { color: var(--gray-soft); display: block; font-size: 13px; letter-spacing: 0.06em; text-transform: uppercase; margin-bottom: 10px; }

/* impact metrics */
.metrics { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; margin: 8px 0 36px; }
.metric .fig { font-size: clamp(34px, 4.4vw, 48px); line-height: 1; letter-spacing: -0.03em; color: var(--ink-strong); }
.metric .cap { margin-top: 12px; font-size: 15px; line-height: 1.5; color: var(--gray); }

/* quotes (interviews / feedback) */
.cs-quotes { display: grid; gap: 14px; margin: 8px 0 0; }
.cs-quote { padding: 26px 30px; background: var(--placeholder); border-radius: 4px; }
.cs-quote.warm { background: #fffdf9; border: 1px solid #efe9dd; }
.cs-quote p { margin: 0; font-size: 18px; line-height: 1.5; letter-spacing: -0.015em; color: var(--ink-strong); text-wrap: pretty; }
.cs-quote cite { display: block; margin-top: 14px; font-style: normal; font-size: 14px; color: var(--gray-soft); letter-spacing: 0.01em; }

/* concept progression */
.cs-progression { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; margin: 8px 0 0; }
.cs-chip { padding: 12px 20px; border: 1px solid var(--line-soft); border-radius: 999px; font-size: 16px; color: var(--gray); }
.cs-chip.active { border-color: var(--ink-strong); color: var(--ink-strong); background: var(--placeholder); }
.cs-progression .sep { color: var(--gray-soft); font-size: 14px; }

/* dimension / feature cards */
.cs-cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin: 8px 0 0; }
.cs-card { padding: 24px; border: 1px solid var(--line-soft); border-radius: 4px; }
.cs-card .ct { font-size: 17px; color: var(--ink-strong); font-weight: 500; margin: 0 0 6px; letter-spacing: -0.01em; }
.cs-card .cd { font-size: 15px; line-height: 1.6; color: var(--gray); margin: 0; }

/* ---------- figures (image slots) ---------- */
.cs-figure { width: min(var(--cs-read), 100% - 2 * var(--cs-gut)); margin: 56px auto 0; }
.cs-figure image-slot { width: 100%; display: block; }
.cs-figure figcaption { margin-top: 14px; font-size: 14px; color: var(--gray-soft); }
.cs-figure.wide { width: min(980px, 100% - 2 * var(--cs-gut)); max-width: none; }

/* before / after comparison */
.cs-ba { width: min(var(--cs-read), 100% - 2 * var(--cs-gut)); margin: 56px auto 0; display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.cs-ba.wide { width: min(980px, 100% - 2 * var(--cs-gut)); }
.cs-ba .col .lbl { font-size: 12px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--gray-soft); margin-bottom: 10px; }
.cs-ba .col image-slot { width: 100%; display: block; }

/* scrollable viewport for long full-page screenshots */
.cs-scroll { width: min(var(--cs-read), 100% - 2 * var(--cs-gut)); margin: 56px auto 0; }
.cs-scroll.wide { width: min(980px, 100% - 2 * var(--cs-gut)); }
.cs-scroll .vp {
  height: 560px; overflow-y: auto; border-radius: 4px;
  background: #fff; border: 1px solid var(--line-soft);
  -webkit-overflow-scrolling: touch;
}
.cs-scroll .vp img { width: 100%; display: block; }
.cs-scroll figcaption { margin-top: 14px; font-size: 14px; color: var(--gray-soft); }
.cs-scroll figcaption .hint { color: var(--gray-soft); opacity: .8; }

/* interview quote cards (research voices) */
.cs-voices { width: min(var(--cs-read), 100% - 2 * var(--cs-gut)); margin: 56px auto 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.voice { background: #fffdf9; border: 1px solid #efe9dd; border-radius: 16px; padding: 26px 24px; display: flex; flex-direction: column; }
.voice .badge { align-self: flex-start; background: #b06a4f; color: #fff; font-size: 14px; letter-spacing: -0.01em; padding: 8px 16px; border-radius: 999px; margin-bottom: 24px; }
.voice .vq { margin: 0 0 24px; font-size: 18px; line-height: 1.45; letter-spacing: -0.015em; color: var(--ink-strong); text-wrap: pretty; }
.voice .vmeta { margin: auto 0 0; font-size: 15px; color: var(--gray-soft); letter-spacing: 0.01em; }

@media (max-width: 760px) {
  .cs-voices { grid-template-columns: 1fr; gap: 16px; }
}

/* browser-framed video (e.g. live-site screen recording) */
.cs-browser { width: min(var(--cs-read), 100% - 2 * var(--cs-gut)); margin: 56px auto 0; border-radius: 8px; overflow: hidden; border: 1px solid var(--line-soft); background: #fff; box-shadow: 0 20px 50px -28px rgba(0,0,0,.28); }
.cs-browser.wide { width: min(980px, 100% - 2 * var(--cs-gut)); }
.cs-browser .bar { display: flex; align-items: center; gap: 14px; padding: 12px 16px; background: var(--placeholder); border-bottom: 1px solid var(--line-soft); }
.cs-browser .dots { display: flex; gap: 7px; }
.cs-browser .dots i { width: 11px; height: 11px; border-radius: 50%; background: #d9d4ca; display: block; }
.cs-browser .addr { flex: 1; font-size: 13px; color: var(--gray-soft); background: #fff; border: 1px solid var(--line-soft); border-radius: 999px; padding: 6px 14px; letter-spacing: .01em; }
.cs-browser .stage { position: relative; aspect-ratio: 16 / 10; background: var(--placeholder); }
.cs-browser .stage video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; display: block; }
.cs-browser .ph { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 6px; text-align: center; color: var(--gray-soft); padding: 24px; }
.cs-browser .ph .big { font-size: 15px; color: var(--gray); }
.cs-browser .ph .sub { font-size: 13px; }
.cs-browser video:not([data-empty]) ~ .ph { display: none; }
.cs-browser video[data-empty] { opacity: 0; }

.cs-divider { width: min(var(--cs-read), 100% - 2 * var(--cs-gut)); margin: 96px auto 0; height: 1px; background: var(--line-soft); }

@media (max-width: 760px) {
  .cs-intro { grid-template-columns: 1fr; gap: 32px; }
  .cs-facts { grid-template-columns: 1fr 1fr; gap: 28px 40px; }
  .metrics { grid-template-columns: 1fr; gap: 24px; }
  .cs-cards { grid-template-columns: 1fr; }
  .cs-ba { grid-template-columns: 1fr; gap: 28px; }
  .cs-section { padding-top: 72px; }
}