/* ==========================================================================
   TANCE — Create & Observe
   Dark Purple Void · Intertwined Neural Threads · Minimal Cyber Art
   ========================================================================== */

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  /* Background layers (deepest → surface) */
  --bg-0: #09090c;
  --bg-1: #0f0f12;
  --bg-2: #14141a;

  /* Accent purple */
  --p-0: #7c3aed;   /* deep */
  --p-1: #8b5cf6;   /* mid */
  --p-2: #a78bfa;   /* soft */

  /* Text */
  --t-0: #ffffff;
  --t-1: #d4d4d8;
  --t-2: #71717a;   /* a quieter grey, used for hints */

  /* Lines */
  --hair: rgba(167, 139, 250, 0.18);
  --hair-strong: rgba(167, 139, 250, 0.45);

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --t: 380ms;

  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "PingFang SC",
    "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", Consolas, Monaco, monospace;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
}

body {
  background: var(--bg-0);
  color: var(--t-1);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.7;
  font-weight: 300;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-weight: 400;
  color: var(--t-0);
  letter-spacing: 0;
}

p { margin: 0; }
ul { margin: 0; padding: 0; list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }
img { max-width: 100%; display: block; }

a {
  color: var(--t-1);
  text-decoration: none;
  transition: color var(--t) var(--ease);
}

a:hover { color: var(--p-2); }

::selection {
  background: var(--p-0);
  color: var(--t-0);
}

/* ---------- Neural net canvas (background) ---------- */
#neural-net {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
  pointer-events: none;
  opacity: 0.85;
}

/* ============================================================
   PAGE: VOID (homepage)
   ============================================================ */
.page-void {
  background:
    radial-gradient(ellipse 80% 60% at 50% 40%, rgba(124, 58, 237, 0.08), transparent 70%),
    var(--bg-0);
}

.void {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  padding: 64px 32px 32px;
}

/* --- Brand (TANCE) --- */
.brand {
  text-align: center;
  flex: 0 0 auto;
  padding: 32px 0 16px;
}

.brand-title {
  font-family: var(--font-sans);
  font-weight: 200;
  font-size: clamp(64px, 13vw, 144px);
  letter-spacing: 0.42em;
  /* shift right by half the letter-spacing so optical center is correct */
  padding-left: 0.42em;
  line-height: 1;
  color: var(--t-0);
  /* faint glow */
  text-shadow: 0 0 32px rgba(167, 139, 250, 0.18);
}

.brand-sub {
  margin-top: 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  font-family: var(--font-mono);
  font-weight: 300;
  font-size: 12px;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--t-2);
}

.brand-sub-en {
  color: var(--p-2);
}

.brand-sub-zh {
  font-family: var(--font-sans);
  letter-spacing: 0.6em;
  padding-left: 0.6em;
  font-size: 11px;
  color: var(--t-2);
}

/* --- The two-card row --- */
.duo {
  flex: 0 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  width: 100%;
  max-width: 880px;
  margin: 48px auto;
}

.duo-card {
  position: relative;
  display: block;
  padding: 36px 32px 32px;
  color: var(--p-2);  /* this drives stroke="currentColor" */
  background: transparent;
  transition: transform var(--t) var(--ease);
  isolation: isolate;
  min-height: 260px;
}

/* SVG frame absolutely fills the card; stroke uses currentColor */
.card-frame {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  overflow: visible;
}

.card-frame-path {
  transition: stroke var(--t) var(--ease), filter var(--t) var(--ease);
  filter: drop-shadow(0 0 0 transparent);
}

/* Solid card background sits under the SVG frame */
.duo-card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--bg-1);
  /* matching asymmetric clip — CREATE: top-right + bottom-left cut */
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 14px 100%, 0 calc(100% - 14px));
  z-index: -2;
  transition: background var(--t) var(--ease);
}

/* OBSERVE mirrors the cuts: top-left + bottom-right */
.duo-card[data-card="observe"]::before {
  clip-path: polygon(14px 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%, 0 14px);
}

/* Body */
.card-body {
  position: relative;
  height: 100%;
  display: flex;
  flex-direction: column;
}

.card-eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--t-2);
  margin-bottom: 18px;
}

.card-title {
  font-family: var(--font-sans);
  font-weight: 300;
  font-size: 30px;
  letter-spacing: 0.18em;
  color: var(--t-0);
  margin-bottom: 8px;
}

.card-line {
  font-size: 13px;
  color: var(--t-1);
  margin-bottom: 24px;
  font-style: italic;
  letter-spacing: 0.02em;
}

.card-list {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  margin-bottom: 28px;
}

.card-list li {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--t-2);
  text-transform: uppercase;
  position: relative;
  transition: color var(--t) var(--ease);
}

.card-list li::before {
  content: "·";
  margin-right: 8px;
  color: var(--p-1);
}

.card-go {
  margin-top: auto;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--t-2);
  display: inline-flex;
  align-items: center;
  gap: 12px;
  transition: color var(--t) var(--ease);
}

.arrow {
  display: inline-block;
  font-style: normal;
  color: var(--p-2);
  transition: transform var(--t) var(--ease), color var(--t) var(--ease);
}

/* Hover */
.duo-card:hover {
  transform: translateY(-3px);
  color: var(--t-0); /* brightens the SVG stroke */
}

.duo-card:hover .card-frame-path {
  stroke: var(--p-2);
  filter: drop-shadow(0 0 8px rgba(167, 139, 250, 0.55));
}

.duo-card:hover::before {
  background: var(--bg-2);
}

.duo-card:hover .card-list li {
  color: var(--t-1);
}

.duo-card:hover .card-go {
  color: var(--p-2);
}

.duo-card:hover .arrow {
  transform: translateX(6px);
}

/* --- Void footer --- */
.void-foot {
  flex: 0 0 auto;
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid var(--hair);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--t-2);
  max-width: 880px;
}

.void-foot-line { color: var(--t-2); font-style: italic; text-transform: none; letter-spacing: 0.08em; }
.void-foot-meta a { color: var(--t-2); }
.void-foot-meta a:hover { color: var(--p-2); }
.void-foot-meta .dot { margin: 0 10px; color: var(--p-1); }

/* ============================================================
   SUB-PAGES (Create / Observe / About / Post / Archive)
   shared minimal header + layout
   ============================================================ */

.sub-header {
  position: relative;
  z-index: 2;
  padding: 40px 32px 0;
  max-width: 1080px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sub-logo {
  font-family: var(--font-sans);
  font-weight: 200;
  font-size: 18px;
  letter-spacing: 0.32em;
  padding-left: 0.32em;
  color: var(--t-0);
}

.sub-logo:hover { color: var(--p-2); }

.sub-nav {
  display: flex;
  gap: 28px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
}

.sub-nav a {
  color: var(--t-2);
  position: relative;
  padding-bottom: 4px;
}

.sub-nav a.is-current {
  color: var(--p-2);
}

.sub-nav a.is-current::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 1px;
  background: var(--p-2);
  box-shadow: 0 0 6px var(--p-2);
}

.sub-shell {
  position: relative;
  z-index: 1;
  max-width: 1080px;
  margin: 0 auto;
  padding: 56px 32px 96px;
}

.sub-head {
  margin-bottom: 56px;
  max-width: 720px;
}

.sub-eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--p-2);
  display: inline-block;
  margin-bottom: 16px;
  padding-left: 18px;
  position: relative;
}

.sub-eyebrow::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 10px;
  height: 1px;
  background: var(--p-2);
}

.sub-title {
  font-family: var(--font-sans);
  font-weight: 200;
  font-size: clamp(38px, 5vw, 64px);
  letter-spacing: 0.08em;
  color: var(--t-0);
  margin-bottom: 14px;
  line-height: 1.1;
}

.sub-line {
  color: var(--t-1);
  font-style: italic;
  font-size: 14px;
  letter-spacing: 0.04em;
  max-width: 560px;
}

/* --- List of entries (used in /create, /observe) --- */
.entry-list {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--hair);
}

.entry {
  display: grid;
  grid-template-columns: 100px 1fr auto;
  gap: 28px;
  align-items: baseline;
  padding: 28px 0;
  border-bottom: 1px solid var(--hair);
  color: var(--t-1);
  transition: background var(--t) var(--ease), padding var(--t) var(--ease);
}

.entry:hover {
  background: linear-gradient(90deg, rgba(124, 58, 237, 0.06), transparent 70%);
  padding-left: 14px;
}

.entry-date {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--t-2);
}

.entry-body { min-width: 0; }

.entry-title {
  font-family: var(--font-sans);
  font-weight: 400;
  font-size: 17px;
  color: var(--t-0);
  margin-bottom: 6px;
  letter-spacing: 0.01em;
  transition: color var(--t) var(--ease);
}

.entry:hover .entry-title { color: var(--p-2); }

.entry-line {
  font-size: 13px;
  color: var(--t-2);
  line-height: 1.65;
  max-width: 620px;
}

.entry-meta {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--t-2);
  white-space: nowrap;
}

.entry-meta .dot { color: var(--p-1); margin: 0 6px; }

/* --- Post detail --- */
.post-shell {
  max-width: 720px;
  margin: 0 auto;
  padding: 56px 32px 96px;
  position: relative;
  z-index: 1;
}

.post-eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--p-2);
  margin-bottom: 22px;
  display: block;
}

.post-h1 {
  font-family: var(--font-sans);
  font-weight: 200;
  font-size: clamp(30px, 4vw, 44px);
  line-height: 1.2;
  letter-spacing: 0.02em;
  color: var(--t-0);
  margin-bottom: 18px;
}

.post-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 18px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--t-2);
  padding-bottom: 28px;
  margin-bottom: 36px;
  border-bottom: 1px solid var(--hair);
}

.post-meta .sep { color: var(--p-1); }

.post-body {
  color: var(--t-1);
  font-size: 16px;
  line-height: 1.85;
}

.post-body p { margin: 0 0 20px; }

.post-body h2 {
  font-family: var(--font-sans);
  font-weight: 300;
  font-size: 22px;
  letter-spacing: 0.05em;
  color: var(--t-0);
  margin: 48px 0 18px;
  padding-left: 18px;
  position: relative;
}

.post-body h2::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 10px;
  height: 1px;
  background: var(--p-2);
  box-shadow: 0 0 6px var(--p-2);
}

.post-body h3 {
  font-family: var(--font-sans);
  font-weight: 400;
  font-size: 16px;
  letter-spacing: 0.04em;
  color: var(--p-2);
  margin: 32px 0 12px;
}

.post-body ul {
  margin: 0 0 20px 0;
  padding-left: 0;
}

.post-body ul li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 8px;
  color: var(--t-1);
}

.post-body ul li::before {
  content: "·";
  position: absolute;
  left: 6px;
  color: var(--p-1);
  font-size: 18px;
}

.post-body strong { color: var(--t-0); font-weight: 500; }

.post-body a { color: var(--p-2); border-bottom: 1px solid var(--hair); transition: border-color var(--t) var(--ease); }
.post-body a:hover { border-bottom-color: var(--p-2); }

.post-body blockquote {
  margin: 22px 0;
  padding: 4px 0 4px 22px;
  border-left: 1px solid var(--p-2);
  color: var(--t-1);
  font-style: italic;
}

.post-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--bg-1);
  border: 1px solid var(--hair);
  padding: 1px 6px;
  border-radius: 3px;
  color: var(--p-2);
}

.post-body pre {
  position: relative;
  background: var(--bg-1);
  border: 1px solid var(--hair);
  border-radius: 4px;
  padding: 18px 20px;
  overflow-x: auto;
  margin: 22px 0;
}

.post-body pre::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 28px;
  height: 1px;
  background: var(--p-2);
  box-shadow: 0 0 8px var(--p-2);
}

.post-body pre code {
  background: none;
  border: none;
  padding: 0;
  color: var(--t-1);
  font-size: 13px;
  line-height: 1.75;
}

.post-foot {
  margin-top: 64px;
  padding-top: 28px;
  border-top: 1px solid var(--hair);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

.post-foot a { color: var(--t-2); }
.post-foot a:hover { color: var(--p-2); }

/* --- About page --- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 48px;
  max-width: 720px;
}

.about-section {
  border-top: 1px solid var(--hair);
  padding-top: 28px;
}

.about-section:first-child { border-top: none; padding-top: 0; }

.about-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--p-2);
  margin-bottom: 18px;
}

.about-body { color: var(--t-1); font-size: 15px; line-height: 1.85; }
.about-body p { margin: 0 0 14px; }
.about-body strong { color: var(--t-0); font-weight: 500; }

.about-rows { display: flex; flex-direction: column; gap: 14px; }

.about-row {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--t-1);
}

.about-row dt {
  color: var(--t-2);
  text-transform: uppercase;
  font-size: 10px;
  letter-spacing: 0.22em;
  padding-top: 2px;
}

.about-row dd { margin: 0; }
.about-row a { color: var(--t-1); border-bottom: 1px solid var(--hair); }
.about-row a:hover { color: var(--p-2); border-bottom-color: var(--p-2); }

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 760px) {
  .void { padding: 32px 20px 24px; }
  .brand { padding: 12px 0 8px; }
  .duo { grid-template-columns: 1fr; gap: 18px; margin: 32px auto; }
  .duo-card { min-height: 220px; padding: 28px 24px; }
  .void-foot {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
  .sub-header { padding: 28px 20px 0; }
  .sub-shell { padding: 40px 20px 64px; }
  .entry {
    grid-template-columns: 1fr;
    gap: 6px;
  }
  .entry-date { margin-bottom: 2px; }
  .post-shell { padding: 40px 20px 64px; }
  .about-row { grid-template-columns: 1fr; gap: 4px; }
}

/* prefers-reduced-motion: stop the canvas animation visually by hiding canvas */
@media (prefers-reduced-motion: reduce) {
  #neural-net { display: none; }
  *, *::before, *::after {
    transition: none !important;
    animation: none !important;
  }
}