/* ============================================================
   PSU AI for Admin Workshop — Site Stylesheet
   Faculty of Technology and Environment · PSU Phuket
   ------------------------------------------------------------
   Design system ported from the ESSM website and tuned to
   Impeccable standards: respect tokens, avoid AI slop,
   serve the workshop's real context.
   ============================================================ */

:root {
  /* PRIMARY — FACULTY PURPLE (สีม่วงคราม) */
  --purple-deep:  #2C2A6E;
  --purple:       #353583;
  --purple-light: #4B4BB0;
  --sritrang:     #B6B8DC;

  /* SECONDARY — PSU INSTITUTIONAL BLUES */
  --psu-deep:     #003C71;
  --psu-blue:     #0061A8;
  --psu-sky:      #009CDE;
  --psu-river:    #59CBE8;
  --psu-river-light: #7AD9F0;

  /* INK & NEUTRALS */
  --ink:          #0E1726;
  --slate:        #586172;
  --line:         #D8DEE7;
  --mist:         #EEF2F7;
  --sand:         #F5F2EC;
  --sand-dark:    #d8d0bf;
  --paper:        #FFFFFF;
  --night:        #0B1020;

  /* TYPOGRAPHY */
  --font-display: "Kanit", "Noto Sans Thai", sans-serif;
  --font-body:    "Sarabun", "Noto Sans Thai", sans-serif;

  --t-mega:  clamp(52px, 11vw, 140px);
  --t-h1:    clamp(38px, 5.5vw, 80px);
  --t-h2:    clamp(28px, 3.2vw, 44px);
  --t-h3:    24px;
  --t-h4:    19px;
  --t-body:  17px;
  --t-small: 15px;
  --t-tag:   12px;

  --lh-display: 0.94;
  --lh-head:    1.08;
  --lh-body:    1.65;

  /* SPACING (8px base) */
  --s-1: 4px;  --s-2: 8px;  --s-3: 12px; --s-4: 16px; --s-5: 24px;
  --s-6: 32px; --s-7: 48px; --s-8: 64px; --s-9: 96px; --s-10: 128px;

  /* RADII */
  --r-sm: 6px; --r-md: 12px; --r-lg: 20px; --r-pill: 999px;

  /* ELEVATION */
  --shadow-sm: 0 1px 3px rgba(14,23,38,.08);
  --shadow-md: 0 8px 28px rgba(14,23,38,.12);
  --shadow-lg: 0 24px 60px rgba(14,23,38,.18);

  /* LAYOUT */
  --maxw: 1200px;
  --gutter: clamp(20px, 5vw, 64px);
}

/* ---- reset ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  font-size: var(--t-body);
  line-height: var(--lh-body);
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}
img, svg { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
::selection { background: var(--psu-river); color: var(--ink); }

/* ---- focus ---- */
a:focus-visible, button:focus-visible, [tabindex]:not([tabindex="-1"]):focus-visible {
  outline: 2px solid var(--psu-river);
  outline-offset: 2px;
}
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--purple-deep);
  color: var(--paper);
  padding: 8px 16px;
  z-index: 100;
  transition: top .2s;
}
.skip-link:focus { top: 0; }

/* ---- layout ---- */
.container { max-width: var(--maxw); margin: 0 auto; padding-left: var(--gutter); padding-right: var(--gutter); }
.section { padding: clamp(56px, 7vw, 104px) 0; }
.section--mist { background: var(--mist); }
.section--sand { background: var(--sand); }
.section--ink  { background: var(--ink); color: var(--paper); }
.section--purple { background: var(--purple-deep); color: var(--paper); }

/* ---- typography ---- */
h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; letter-spacing: -.025em; }
h1 { font-size: var(--t-h1); line-height: var(--lh-head); }
h2 { font-size: var(--t-h2); line-height: var(--lh-head); }
h3 { font-size: var(--t-h3); line-height: 1.18; }
h4 { font-size: var(--t-h4); line-height: 1.22; }
.display { font-family: var(--font-display); font-weight: 700; line-height: var(--lh-display); letter-spacing: -.03em; }
.lead { font-size: clamp(16px, 1.3vw, 19px); line-height: 1.65; color: var(--slate); max-width: 56ch; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--font-display); font-weight: 500;
  font-size: var(--t-tag); letter-spacing: .14em; text-transform: uppercase;
  color: var(--slate);
}
.eyebrow .route-line { width: 26px; height: 1.5px; background: var(--line); }
.eyebrow .route-dot  { width: 6px; height: 6px; border-radius: 50%; background: var(--purple); }

/* ---- header ---- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.92); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--mist);
}
.nav__container {
  max-width: var(--maxw); margin: 0 auto;
  padding: 14px var(--gutter);
  display: flex; align-items: center; justify-content: space-between; gap: 20px;
}
.nav__brand {
  font-family: var(--font-display); font-weight: 600; font-size: 18px;
  color: var(--purple-deep); letter-spacing: -.01em;
}
.nav__links {
  display: flex; align-items: center; gap: clamp(16px, 1.8vw, 28px);
  list-style: none; flex-wrap: wrap;
}
.nav__links a {
  font-family: var(--font-display); font-weight: 400; font-size: 14.5px;
  color: var(--ink); transition: color .15s ease;
}
.nav__links a:hover { color: var(--purple); }
.nav__links a[aria-current="page"] { color: var(--purple-deep); font-weight: 500; }

/* ---- buttons ---- */
.button, .hero__cta {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: var(--font-display); font-weight: 500; font-size: 15px;
  padding: 13px 26px; border-radius: var(--r-pill);
  cursor: pointer; border: 1.5px solid transparent;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease, border-color .18s ease;
}
.button:focus-visible, .hero__cta:focus-visible { outline: none; box-shadow: 0 0 0 3px rgba(89,203,232,.55); }
.button {
  background: var(--purple); color: var(--paper);
}
.button:hover { background: var(--purple-light); transform: translateY(-2px); box-shadow: 0 10px 24px rgba(53,53,131,.35); }
.button--river {
  background: var(--psu-river); color: var(--ink);
}
.button--river:hover { background: var(--psu-river-light); box-shadow: 0 10px 24px rgba(89,203,232,.45); }
.button--ghost {
  background: transparent; color: var(--purple-deep); border-color: var(--purple-deep);
}
.button--ghost:hover { background: var(--mist); }

/* ---- hero ---- */
.hero {
  position: relative;
  background: var(--night);
  color: var(--paper);
  padding: clamp(80px, 14vh, 160px) 0 clamp(100px, 16vh, 180px);
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse 60% 70% at 74% 26%, rgba(89,203,232,.32), transparent 60%),
    radial-gradient(ellipse 50% 60% at 82% 40%, rgba(182,184,220,.22), transparent 55%),
    linear-gradient(125deg, rgba(44,42,110,.78) 0%, rgba(53,53,131,.58) 45%, rgba(0,60,113,.52) 100%);
}
.hero::after {
  content: "";
  position: absolute; inset: 0; opacity: .35;
  background: repeating-linear-gradient(122deg, transparent 0 26px, rgba(255,255,255,.04) 26px 27px);
}
.hero .container { position: relative; z-index: 2; }
.hero__eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--font-display); font-weight: 500;
  font-size: var(--t-tag); letter-spacing: .14em; text-transform: uppercase;
  color: var(--psu-river); margin-bottom: var(--s-5);
}
.hero__eyebrow::before {
  content: "";
  width: 26px; height: 1.5px; background: var(--psu-river);
}
.hero h1 {
  font-size: var(--t-h1);
  line-height: var(--lh-display);
  color: var(--paper);
  max-width: 14ch;
}
.hero h1 span { font-weight: 300; }
.hero__meta {
  font-size: clamp(16px, 1.4vw, 19px);
  line-height: 1.6;
  color: rgba(255,255,255,.72);
  max-width: 56ch;
  margin-top: var(--s-5);
}
.hero__cta {
  background: var(--psu-river); color: var(--ink);
  margin-top: var(--s-6);
}
.hero__cta:hover { background: var(--psu-river-light); transform: translateY(-2px); box-shadow: 0 10px 24px rgba(89,203,232,.45); }
.hero__cta--ghost {
  background: transparent; color: var(--paper); border-color: var(--paper); border-width: 1.5px;
  margin-top: var(--s-6); margin-left: var(--s-3);
}
.hero__cta--ghost:hover { background: rgba(255,255,255,.12); box-shadow: 0 10px 24px rgba(255,255,255,.12); }

/* ---- cards ---- */
.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: clamp(24px, 3vw, 40px);
  box-shadow: var(--shadow-sm);
}
.card h2 { color: var(--purple-deep); margin-bottom: var(--s-4); }
.card h3 { color: var(--purple-deep); margin-bottom: var(--s-3); }

/* ---- resource grid ---- */
.resource-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--s-5);
}
.resource-card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: var(--s-6);
  box-shadow: var(--shadow-sm);
  transition: transform .18s ease, box-shadow .18s ease;
  display: flex; flex-direction: column;
}
.resource-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.resource-card h3 { color: var(--purple-deep); font-size: 21px; margin-bottom: var(--s-3); }
.resource-card p { color: var(--slate); margin-bottom: var(--s-5); flex: 1; }

/* ---- timeline ---- */
.timeline { list-style: none; }
.timeline__item {
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: var(--s-5);
  padding: var(--s-5) 0;
  border-bottom: 1px solid var(--line);
}
.timeline__item:last-child { border-bottom: none; }
.timeline__time {
  font-family: var(--font-display); font-weight: 500;
  font-size: 14px; letter-spacing: .04em;
  color: var(--purple); text-transform: uppercase;
}
.timeline__content { color: var(--ink); }

/* ---- lists ---- */
ul:not(.nav__links):not(.timeline):not(.rules), ol {
  padding-left: 1.4em;
}
ul:not(.nav__links):not(.timeline):not(.rules) li, ol li {
  margin-bottom: var(--s-3);
}

/* ---- notices ---- */
.notice {
  border-left: 3px solid var(--psu-river);
  background: var(--mist);
  padding: var(--s-5);
  border-radius: 0 var(--r-md) var(--r-md) 0;
  margin: var(--s-6) 0;
}
.notice--warning { border-left-color: var(--psu-sky); background: #e8f6fc; }
.notice--info { border-left-color: var(--psu-river); background: var(--mist); }

/* ---- exercises ---- */
.exercise {
  padding: var(--s-8) 0;
  border-bottom: 1px solid var(--line);
}
.exercise:first-of-type { padding-top: 0; }
.exercise:last-child { border-bottom: none; }
.exercise__header {
  display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between;
  gap: var(--s-3); margin-bottom: var(--s-4);
}
.exercise__title { color: var(--purple-deep); font-size: var(--t-h2); }
.exercise__time {
  font-family: var(--font-display); font-weight: 500;
  font-size: 14px; letter-spacing: .06em; text-transform: uppercase;
  color: var(--purple);
}
.exercise__tool {
  display: inline-block;
  font-family: var(--font-display); font-size: 13px;
  color: var(--slate); margin-bottom: var(--s-5);
}
.exercise h3 { color: var(--purple-deep); margin: var(--s-6) 0 var(--s-3); }
.exercise ol.steps { padding-left: 1.4em; }
.exercise ol.steps li { margin-bottom: var(--s-3); }

.prompt-box {
  position: relative;
  background: var(--sand);
  border: 1px solid var(--sand-dark);
  border-radius: var(--r-md);
  padding: var(--s-5);
  font-family: var(--font-body);
  font-size: 15.5px;
  line-height: 1.7;
  white-space: pre-wrap;
  margin: var(--s-5) 0;
}

.copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: var(--purple-deep);
  color: #fff;
  border: none;
  border-radius: 999px;
  padding: 0.35rem 0.9rem;
  font-family: var(--font-display);
  font-size: 0.8rem;
  cursor: pointer;
  opacity: 0.9;
  transition: opacity 0.2s ease, background 0.2s ease;
}
.copy-btn:hover { opacity: 1; background: var(--purple-mid); }
.copy-btn:active { transform: translateY(1px); }

.exercise details {
  background: var(--mist);
  border-radius: var(--r-md);
  padding: var(--s-5);
  margin: var(--s-6) 0;
}
.exercise details summary {
  font-family: var(--font-display); font-weight: 600;
  color: var(--purple-deep); cursor: pointer;
}
.exercise details[open] summary { margin-bottom: var(--s-4); }

.exercise table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--s-5) 0;
  font-size: 15px;
}
.exercise table th, .exercise table td {
  padding: var(--s-3) var(--s-4);
  border: 1px solid var(--line);
  text-align: left;
}
.exercise table th { background: var(--mist); font-family: var(--font-display); font-weight: 600; color: var(--purple-deep); }

/* ---- rules / troubleshooting ---- */
.rules {
  list-style: none; padding: 0;
}
.rules li {
  padding: var(--s-3) 0 var(--s-3) 28px;
  position: relative;
  border-bottom: 1px solid var(--line);
}
.rules li:last-child { border-bottom: none; }
.rules li::before {
  content: "✓";
  position: absolute; left: 0; top: var(--s-3);
  color: var(--purple); font-weight: 700;
}

/* ---- footer ---- */
.footer {
  background: var(--night);
  color: rgba(255,255,255,.6);
  padding: var(--s-7) 0;
  font-size: 14px;
}
.footer__version {
  margin-top: var(--s-3);
  font-size: 12px;
  color: rgba(255,255,255,.4);
}

/* ---- materials page ---- */
.materials-list {
  list-style: none; padding: 0;
}
.materials-list li {
  border-bottom: 1px solid var(--line);
  padding: var(--s-5) 0;
}
.materials-list li:last-child { border-bottom: none; }
.materials-list a {
  font-family: var(--font-display); font-weight: 600;
  font-size: 18px; color: var(--purple-deep);
}
.materials-list a:hover { color: var(--purple); }
.materials-list p { color: var(--slate); margin-top: var(--s-2); }

/* ---- display page ---- */
.display-page {
  display: grid;
  grid-template-rows: auto 1fr auto;
  min-height: 100vh;
  background: var(--night);
  color: var(--paper);
}
.display-page header {
  display: flex; justify-content: space-between; align-items: center;
  padding: var(--s-5) var(--gutter);
  border-bottom: 1px solid rgba(255,255,255,.12);
}
.display-page header h1 {
  font-size: clamp(22px, 3vw, 34px);
  color: var(--paper);
}
.display-page .status { color: rgba(255,255,255,.7); font-size: clamp(14px, 2vw, 18px); }
.display-page main {
  display: grid; grid-template-columns: 2fr 1fr; gap: var(--s-6);
  padding: var(--s-6) var(--gutter);
  align-items: start;
}
.countdown-box {
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.14);
  border-radius: var(--r-lg);
  padding: var(--s-7) var(--s-6);
  text-align: center;
}
.countdown-label {
  font-family: var(--font-display); font-weight: 500;
  font-size: clamp(18px, 2.5vw, 28px);
  color: rgba(255,255,255,.75);
  margin-bottom: var(--s-5);
}
.countdown-time {
  font-family: var(--font-display); font-weight: 700;
  font-size: clamp(64px, 14vw, 160px);
  line-height: .9;
  color: var(--psu-river);
  font-variant-numeric: tabular-nums;
}
.current-exercise {
  margin-top: var(--s-6);
  padding: var(--s-4) var(--s-5);
  background: var(--psu-river);
  color: var(--ink);
  border-radius: var(--r-md);
  font-family: var(--font-display); font-weight: 700;
  font-size: clamp(16px, 2vw, 24px);
}
.display-side {
  display: flex; flex-direction: column; gap: var(--s-5);
}
.display-card {
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.14);
  border-radius: var(--r-lg);
  padding: var(--s-5);
}
.display-card h2 {
  color: var(--psu-river);
  font-size: 18px;
  margin-bottom: var(--s-4);
}
.display-schedule {
  width: 100%; border-collapse: collapse;
  font-size: clamp(14px, 1.5vw, 17px);
}
.display-schedule td {
  padding: var(--s-3) 0;
  border-bottom: 1px solid rgba(255,255,255,.1);
  vertical-align: top;
}
.display-schedule tr:last-child td { border-bottom: none; }
.display-schedule .time { white-space: nowrap; font-weight: 600; width: 38%; color: rgba(255,255,255,.75); }
.display-schedule .active { background: var(--psu-river); color: var(--ink); font-weight: 700; border-radius: var(--r-sm); }
.display-schedule .active .time { color: var(--ink); }
.display-rules { list-style: none; padding: 0; font-size: clamp(14px, 1.5vw, 17px); }
.display-rules li {
  padding: var(--s-3) 0 var(--s-3) 26px;
  position: relative;
}
.display-rules li::before {
  content: "✓";
  position: absolute; left: 0;
  color: var(--psu-river); font-weight: 700;
}
.display-links { font-size: clamp(14px, 1.5vw, 17px); line-height: 1.55; }
.display-links a { color: var(--psu-river); word-break: break-all; }
.display-page footer {
  text-align: center;
  padding: var(--s-4) var(--gutter);
  border-top: 1px solid rgba(255,255,255,.12);
  color: rgba(255,255,255,.55);
}
.display-page footer .footer__version {
  color: rgba(255,255,255,.35);
  font-size: 12px;
  margin-left: 4px;
}

/* ---- responsive ---- */
@media (max-width: 900px) {
  .hero h1 { max-width: 100%; }
  .timeline__item { grid-template-columns: 1fr; gap: var(--s-2); }
  .display-page main { grid-template-columns: 1fr; }
  .display-page header { flex-direction: column; align-items: flex-start; gap: var(--s-3); }
}

@media (max-width: 640px) {
  .nav__container { flex-wrap: wrap; }
  .nav__links { gap: 14px; }
  .resource-grid { grid-template-columns: 1fr; }
  .hero { padding: 64px 0 80px; }
}

/* ---- kbd ---- */
kbd {
  display: inline-block;
  background: var(--night);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 0.85em;
  padding: 0.15em 0.55em;
  border-radius: var(--r-sm);
  box-shadow: 0 2px 0 rgba(0,0,0,.2);
}

/* ---- print ---- */
@media print {
  .nav, .footer, .hero__cta, .skip-link, .copy-btn { display: none !important; }
  body { font-size: 11pt; color: #000; background: #fff; }
  a { color: #000; text-decoration: underline; }
  a[href]::after { content: " (" attr(href) ")"; font-size: 0.8em; word-break: break-all; }
  .hero { padding: 20px 0; }
  .section { padding: 18px 0; }
  .prompt-box { background: #f5f5f5; border: 1px solid #ddd; }
  details { display: block; }
  details summary { font-weight: 700; }
  .prompt-box, .exercise details, .card, .resource-card { page-break-inside: avoid; }
  h2, h3 { page-break-after: avoid; }
  .exercise { page-break-before: auto; }
}