/* ==========================================================================
   How Paper Becomes Packaging — kraft/paper visual theme
   ========================================================================== */

:root {
  --paper: #f7f2e8;
  --paper-deep: #efe7d6;
  --card: #fffdf7;
  --ink: #2e2a23;
  --ink-soft: #5c5347;
  --kraft: #b08d57;
  --kraft-deep: #8a6a3d;
  /* Brand accents — forest & lime green (Bel brand palette) */
  --forest: #1f4d2c;
  --forest-deep: #143620;
  --lime: #8dc63f;
  --lime-deep: #5f8f26;
  --lime-soft: #eef6da;
  --green: #1f4d2c;
  --green-soft: #dfead9;
  --terracotta: #c26d4b;
  --terracotta-soft: #f4e2d8;
  --line: #e2d8c2;
  --bad: #a8442e;
  --good: #1f4d2c;
  --radius: 14px;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

/* ---------- Paper texture (seamless grain over the whole site) ----------
   A self-contained fractal-noise tile (stitchTiles="stitch" => seams-free)
   overlaid on everything and repeated horizontally + vertically. */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='200' height='200'><filter id='pt'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/><feColorMatrix type='saturate' values='0'/></filter><rect width='100%25' height='100%25' filter='url(%23pt)'/></svg>");
  background-repeat: repeat;
  background-size: 200px 200px;
  mix-blend-mode: overlay;
  opacity: 0.55;
}
@media print { body::after { display: none; } }

html { scroll-behavior: smooth; scroll-padding-top: 76px; }

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.65;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    radial-gradient(circle at 15% 20%, rgba(176, 141, 87, 0.05), transparent 40%),
    radial-gradient(circle at 85% 70%, rgba(31, 77, 44, 0.045), transparent 45%),
    radial-gradient(circle at 50% 100%, rgba(141, 198, 63, 0.04), transparent 50%);
}

h1, h2, h3, h4 { font-family: var(--serif); line-height: 1.25; color: var(--ink); }
h2 { font-size: 1.9rem; margin: 0 0 0.4rem; }
h3 { font-size: 1.25rem; margin: 1.6rem 0 0.5rem; }
p { margin: 0.6rem 0 1rem; }
a { color: var(--green); }

.small { font-size: 0.88rem; color: var(--ink-soft); }
.center { text-align: center; }

/* ---------- Nav ---------- */

.topnav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(247, 242, 232, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.topnav-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0.55rem 1rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* ---------- Language slider ---------- */

.lang-switch {
  flex-shrink: 0;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: 0;
  border: none;
  background: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.ls-track {
  position: relative;
  width: 62px;
  height: 28px;
  border-radius: 999px;
  overflow: hidden;
  border: 1px solid #b9b4a7;
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.28);
  background: #d7d2c6;
}
/* Both flags live in the track, each filling one half — always visible. */
.ls-half {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 50%;
  overflow: hidden;
  opacity: 0.5;
  filter: saturate(0.85);
}
.ls-half-en { left: 0; }
.ls-half-fr { right: 0; }
.ls-half svg { width: 100%; height: 100%; display: block; }
/* The uncovered (target) flag reads brighter; the covered one dims behind the knob. */
.lang-switch.is-en .ls-half-fr,
.lang-switch.is-fr .ls-half-en { opacity: 0.9; filter: none; }

/* Sliding knob carries the active flag. */
.ls-knob {
  position: absolute;
  top: 2px;
  left: 2px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  overflow: hidden;
  border: 2px solid #fff;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.4), inset 0 1px 1px rgba(255, 255, 255, 0.5);
  transition: left 0.25s cubic-bezier(0.4, 0.1, 0.2, 1);
  background: #eee;
}
.lang-switch.is-fr .ls-knob { left: calc(100% - 26px); }
.ls-knob-flag { position: absolute; inset: 0; }
.ls-knob-flag svg { width: 100%; height: 100%; display: block; }
.lang-switch.is-en .ls-knob-fr,
.lang-switch.is-fr .ls-knob-en { display: none; }

.lang-switch:hover .ls-track { border-color: var(--forest); }
.lang-switch:focus-visible { outline: none; }
.lang-switch:focus-visible .ls-track { outline: 2px solid var(--forest); outline-offset: 2px; }

.ls-labels {
  display: flex;
  justify-content: space-between;
  width: 62px;
  font-size: 0.56rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--ink-soft);
  line-height: 1;
}
.lang-switch.is-en .ls-lbl-en,
.lang-switch.is-fr .ls-lbl-fr { color: var(--forest); }
.lang-switch.is-en .ls-lbl-fr,
.lang-switch.is-fr .ls-lbl-en { opacity: 0.5; }
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.02rem;
  color: var(--forest);
  text-decoration: none;
  white-space: nowrap;
}
.brand-icon {
  width: 2rem;
  height: 2rem;
  flex: 0 0 auto;
  border-radius: 50%;
  object-fit: cover;
}
.navlinks {
  display: flex;
  gap: 0.15rem;
  flex: 1;
  min-width: 0;
  overflow-x: auto;
  scrollbar-width: none;
}
.navlinks::-webkit-scrollbar { display: none; }
.navlinks a {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 0.86rem;
  padding: 0.35rem 0.6rem;
  border-radius: 999px;
  white-space: nowrap;
}
.navlinks a:hover { background: var(--paper-deep); color: var(--ink); }
.navlinks a.active { background: var(--green); color: #fff; }

@media (max-width: 640px) {
  html { scroll-padding-top: 7rem; }
  .topnav-inner {
    flex-wrap: wrap;
    gap: 0.35rem 0.75rem;
    padding: 0.5rem 1.25rem;
  }
  .navlinks {
    order: 3;
    flex: 0 0 100%;
  }
}

/* ---------- Layout ---------- */

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 1rem; }

@media (max-width: 640px) {
  .wrap { padding-left: 1.25rem; padding-right: 1.25rem; }
  .hero .kicker,
  .hero .lede {
    max-width: calc(100% - 1rem);
    margin-left: auto;
    margin-right: auto;
  }
  .hero .kicker {
    display: block;
    overflow-wrap: anywhere;
  }
}

section.block { padding: 3.2rem 0 1.4rem; }
section.block + section.block { border-top: 1px dashed var(--line); }

.kicker {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--lime-deep);
  margin-bottom: 0.35rem;
}
.lede { font-size: 1.08rem; color: var(--ink-soft); max-width: 46rem; }

/* ---------- Hero ---------- */

.hero { padding: 4.2rem 0 2.6rem; text-align: center; }
.hero h1 {
  font-size: clamp(2.1rem, 5.5vw, 3.4rem);
  margin: 0.4rem 0 0.8rem;
}
.hero h1 em { color: var(--forest); font-style: italic; }
.hero .lede { margin: 0 auto 1.4rem; }
.hero-chips { display: flex; flex-wrap: wrap; gap: 0.5rem; justify-content: center; }
.hero-chips a {
  text-decoration: none;
  font-size: 0.85rem;
  padding: 0.42rem 0.9rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--card);
  color: var(--ink-soft);
}
.hero-chips a:hover { border-color: var(--lime-deep); color: var(--forest); }

/* ---------- Cards & grids ---------- */

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.15rem 1.3rem;
  box-shadow: 0 1px 3px rgba(80, 62, 30, 0.05);
}
.grid { display: grid; gap: 1rem; margin: 1.2rem 0; }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 820px) {
  .grid.cols-3 { grid-template-columns: 1fr; }
  .grid.cols-2 { grid-template-columns: 1fr; }
}

.card h3 { margin-top: 0.2rem; }
.card .icon { font-size: 1.6rem; }

.callout {
  border-left: 4px solid var(--forest);
  background: var(--card);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 0.9rem 1.2rem;
  margin: 1.2rem 0;
}
.callout.green { border-left-color: var(--lime-deep); }
.callout.terra { border-left-color: var(--terracotta); }
.callout strong:first-child { color: var(--forest); }

/* ---------- Chips / tags ---------- */

.chip {
  display: inline-block;
  font-size: 0.76rem;
  font-weight: 600;
  padding: 0.14rem 0.6rem;
  border-radius: 999px;
  margin: 0.12rem 0.18rem 0.12rem 0;
  background: var(--green-soft);
  color: var(--green);
}
.chip.warn { background: var(--terracotta-soft); color: var(--bad); }
.chip.neutral { background: var(--paper-deep); color: var(--ink-soft); }

/* ---------- Tabs (grade explorer, chat settings) ---------- */

.tabs { display: flex; flex-wrap: wrap; gap: 0.45rem; margin: 1.1rem 0 0.9rem; }
.tabs button {
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.45rem 1rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink-soft);
  cursor: pointer;
}
.tabs button:hover { border-color: var(--lime-deep); }
.tabs button.active { background: var(--green); border-color: var(--green); color: #fff; }

.panel { display: none; }
.panel.active { display: block; }

/* ---------- Grade explorer ---------- */

.grade-panel { display: grid; grid-template-columns: 300px 1fr; gap: 1.4rem; align-items: start; }
@media (max-width: 820px) { .grade-panel { grid-template-columns: 1fr; } }
.ply-diagram { width: 100%; height: auto; }
.grade-fullname { color: var(--forest); font-style: italic; margin-top: -0.3rem; }

.propbars { margin: 0.9rem 0; }
.propbar { display: grid; grid-template-columns: 11rem 1fr 2.6rem; align-items: center; gap: 0.6rem; margin: 0.32rem 0; font-size: 0.85rem; }
.propbar .track { background: var(--paper-deep); border-radius: 999px; height: 9px; overflow: hidden; }
.propbar .fill { height: 100%; border-radius: 999px; background: linear-gradient(90deg, var(--kraft), var(--kraft-deep)); }
.propbar.green .fill { background: linear-gradient(90deg, var(--lime), var(--forest)); }

/* ---------- Stepper (paper machine) ---------- */

.stepper { display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 1.1rem 0; counter-reset: step; }
.stepper button {
  font: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.4rem 0.75rem;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink-soft);
  cursor: pointer;
}
.stepper button.active { background: var(--lime-deep); border-color: var(--lime-deep); color: #fff; }
.step-detail { min-height: 9rem; }
.step-detail .water-meter { margin-top: 0.8rem; }

.water-meter { font-size: 0.82rem; color: var(--ink-soft); }
.water-meter .track { background: #dde8f0; height: 12px; border-radius: 999px; overflow: hidden; margin-top: 0.25rem; }
.water-meter .fill { height: 100%; background: linear-gradient(90deg, #7aa7c4, #48738f); border-radius: 999px; transition: width 0.4s ease; }

/* ---------- Flute selector ---------- */

.flute-wrap { display: grid; grid-template-columns: 1fr 320px; gap: 1.4rem; align-items: start; }
@media (max-width: 820px) { .flute-wrap { grid-template-columns: 1fr; } }
.flute-svg { width: 100%; height: auto; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); }
table.stats { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
table.stats td { padding: 0.4rem 0.5rem; border-bottom: 1px solid var(--line); }
table.stats td:first-child { color: var(--ink-soft); }
table.stats tr:last-child td { border-bottom: none; }

.table-scroll { overflow-x: auto; }
table.compare { width: 100%; border-collapse: collapse; font-size: 0.88rem; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); }
table.compare th, table.compare td { padding: 0.5rem 0.7rem; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
table.compare th { background: var(--paper-deep); font-family: var(--serif); }

/* ---------- Coating cards ---------- */

.coating-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin: 1.2rem 0; }
@media (max-width: 900px) { .coating-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .coating-grid { grid-template-columns: 1fr; } }
.coating-card { cursor: pointer; transition: transform 0.12s ease, box-shadow 0.12s ease; }
.coating-card:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(80, 62, 30, 0.1); }
.coating-card.open { border-color: var(--forest); }
.coating-card .detail { display: none; margin-top: 0.6rem; border-top: 1px dashed var(--line); padding-top: 0.6rem; }
.coating-card.open .detail { display: block; }

.recycle-meter { display: flex; align-items: center; gap: 0.5rem; font-size: 0.8rem; margin-top: 0.5rem; }
.recycle-meter .dots { display: flex; gap: 3px; }
.recycle-meter .dot { width: 11px; height: 11px; border-radius: 50%; background: var(--paper-deep); border: 1px solid var(--line); }
.recycle-meter .dot.on { background: var(--lime); border-color: var(--lime-deep); }

/* ---------- Converter ---------- */

.converter { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
@media (max-width: 820px) { .converter { grid-template-columns: 1fr; } }
.converter label { display: block; font-size: 0.8rem; font-weight: 700; color: var(--ink-soft); margin-bottom: 0.25rem; }
.converter input {
  width: 100%;
  font: inherit;
  padding: 0.5rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  color: var(--ink);
}
.converter input:focus { outline: 2px solid var(--forest); border-color: var(--forest); }
.converter .hint { font-size: 0.78rem; color: var(--ink-soft); margin-top: 0.3rem; }

/* ---------- Quiz ---------- */

.quiz-q { margin-bottom: 1.3rem; }
.quiz-q .qtext { font-weight: 700; margin-bottom: 0.5rem; }
.quiz-q .opts { display: grid; gap: 0.4rem; }
.quiz-q .opts button {
  font: inherit;
  text-align: left;
  padding: 0.55rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--card);
  cursor: pointer;
  color: var(--ink);
}
.quiz-q .opts button:hover:not(:disabled) { border-color: var(--forest); }
.quiz-q .opts button.correct { background: var(--green-soft); border-color: var(--good); }
.quiz-q .opts button.wrong { background: var(--terracotta-soft); border-color: var(--bad); }
.quiz-q .explain { display: none; font-size: 0.88rem; color: var(--ink-soft); margin-top: 0.5rem; }
.quiz-q.answered .explain { display: block; }
#quiz-score { font-weight: 700; }

/* ---------- Glossary ---------- */

details.glossary {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.8rem 1.2rem;
  margin: 1.2rem 0;
}
details.glossary summary { font-family: var(--serif); font-weight: 700; font-size: 1.05rem; cursor: pointer; }
.glossary dl { display: grid; grid-template-columns: 11rem 1fr; gap: 0.35rem 1rem; font-size: 0.9rem; margin-top: 0.8rem; }
@media (max-width: 640px) { .glossary dl { grid-template-columns: 1fr; } }
.glossary dt { font-weight: 700; color: var(--forest); }
.glossary dd { margin: 0; color: var(--ink-soft); }

/* ---------- Chat ---------- */

.chat-shell { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; margin: 1.2rem 0; }
.chat-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--line);
  background: var(--paper-deep);
}
.chat-head .mode { font-size: 0.8rem; color: var(--ink-soft); }
.chat-head button {
  font: inherit;
  font-size: 0.82rem;
  padding: 0.3rem 0.8rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--card);
  cursor: pointer;
  color: var(--ink-soft);
}
.chat-head button:hover { border-color: var(--forest); color: var(--forest); }

.chat-log { max-height: 430px; overflow-y: auto; padding: 1rem; display: flex; flex-direction: column; gap: 0.7rem; }
.msg { max-width: 85%; padding: 0.6rem 0.9rem; border-radius: 14px; font-size: 0.94rem; white-space: pre-wrap; overflow-wrap: break-word; }
.msg.user { align-self: flex-end; background: var(--green); color: #fff; border-bottom-right-radius: 4px; }
.msg.bot { align-self: flex-start; background: var(--paper-deep); border-bottom-left-radius: 4px; }
.msg.bot.error { background: var(--terracotta-soft); color: var(--bad); }
.msg .src { display: block; font-size: 0.72rem; opacity: 0.65; margin-top: 0.35rem; }

.chat-suggest { display: flex; flex-wrap: wrap; gap: 0.4rem; padding: 0 1rem 0.7rem; }
.chat-suggest button {
  font: inherit;
  font-size: 0.78rem;
  padding: 0.28rem 0.7rem;
  border-radius: 999px;
  border: 1px dashed var(--line);
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
}
.chat-suggest button:hover { border-color: var(--lime-deep); color: var(--forest); }

.chat-input { display: flex; gap: 0.5rem; padding: 0.8rem 1rem; border-top: 1px solid var(--line); }
.chat-input textarea {
  flex: 1;
  font: inherit;
  font-size: 0.94rem;
  padding: 0.55rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  resize: none;
  background: #fff;
  color: var(--ink);
}
.chat-input textarea:focus { outline: 2px solid var(--forest); border-color: var(--forest); }
.chat-input button {
  font: inherit;
  font-weight: 700;
  padding: 0 1.3rem;
  border: none;
  border-radius: 10px;
  background: var(--green);
  color: #fff;
  cursor: pointer;
}
.chat-input button:disabled { opacity: 0.5; cursor: default; }

.chat-settings { display: none; padding: 1rem; border-top: 1px solid var(--line); background: var(--paper); }
.chat-settings.open { display: block; }
.chat-settings h4 { margin: 0 0 0.5rem; }
.chat-settings .field { margin-bottom: 0.8rem; }
.chat-settings label { display: block; font-size: 0.82rem; font-weight: 700; margin-bottom: 0.25rem; color: var(--ink-soft); }
.chat-settings input[type="text"], .chat-settings input[type="password"] {
  width: 100%;
  font: inherit;
  font-size: 0.9rem;
  padding: 0.45rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}
.chat-settings .radio-row { display: flex; flex-direction: column; gap: 0.4rem; margin-bottom: 0.9rem; font-size: 0.9rem; }
.chat-settings .radio-row label { font-weight: 400; display: flex; gap: 0.5rem; align-items: baseline; margin: 0; color: var(--ink); }
.chat-settings .note { font-size: 0.78rem; color: var(--ink-soft); }
.chat-settings .save-row { display: flex; gap: 0.6rem; align-items: center; margin-top: 0.6rem; }
.chat-settings .save-row button {
  font: inherit;
  font-weight: 700;
  font-size: 0.88rem;
  padding: 0.4rem 1.1rem;
  border: none;
  border-radius: 8px;
  background: var(--green);
  color: #fff;
  cursor: pointer;
}
.chat-settings .saved-flash { font-size: 0.82rem; color: var(--good); opacity: 0; transition: opacity 0.3s; }
.chat-settings .saved-flash.show { opacity: 1; }

.typing { display: inline-block; }
.typing span { display: inline-block; width: 6px; height: 6px; margin-right: 3px; border-radius: 50%; background: var(--ink-soft); animation: blink 1.2s infinite; }
.typing span:nth-child(2) { animation-delay: 0.2s; }
.typing span:nth-child(3) { animation-delay: 0.4s; }
@keyframes blink { 0%, 80%, 100% { opacity: 0.25; } 40% { opacity: 1; } }

/* ---------- Footer ---------- */

footer { border-top: 1px solid var(--line); margin-top: 3rem; padding: 1.6rem 0 0.4rem; font-size: 0.85rem; color: var(--ink-soft); }

.footer-signoff {
  max-width: 1080px;
  margin: 0.8rem auto 0;
  padding: 0.6rem 1rem 0.2rem;
  border-top: 1px dashed var(--line);
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 1rem;
  font-size: 0.76rem;
  color: var(--ink-soft);
}
.footer-signoff .footer-left { font-weight: 600; color: #8a8175; }
.footer-signoff .footer-right { text-align: right; color: #8a8175; opacity: 1; }
@media (max-width: 480px) {
  .footer-signoff { flex-direction: column; align-items: flex-start; gap: 0.3rem; padding-left: 1.25rem; padding-right: 1.25rem; }
  .footer-signoff .footer-right { text-align: left; }
}