/* SPARK-AI student experience v2
   Loaded after spark-base.css so existing application logic and DOM IDs remain intact. */

:root {
  --spark-radius-xl: 30px;
  --spark-radius-lg: 22px;
  --spark-radius-md: 16px;
  --spark-header-height: 76px;
  --spark-content: 1380px;
}

body.spark-student-page {
  overflow-x: hidden;
}

body.spark-student-page > header {
  min-height: var(--spark-header-height);
  padding: 10px max(20px, calc((100vw - var(--spark-content)) / 2));
  gap: 18px;
  border-bottom: 1px solid color-mix(in srgb, var(--spark-border) 78%, transparent);
  background: color-mix(in srgb, var(--spark-surface-solid) 86%, transparent);
  box-shadow: 0 10px 35px color-mix(in srgb, var(--spark-text) 7%, transparent);
  backdrop-filter: blur(18px) saturate(140%);
}

body.spark-student-page > header .logo-container,
body.spark-forum > header .brand-lockup {
  display: flex;
  min-width: 0;
  align-items: center;
  gap: 13px;
}

body.spark-student-page > header img {
  width: 52px;
  height: 52px;
  flex: 0 0 auto;
  object-fit: contain;
  border: 1px solid var(--spark-border);
  border-radius: 16px;
  background: #fff;
  box-shadow: 0 9px 24px rgba(25, 45, 80, .12);
}

body.spark-student-page .main-title,
body.spark-student-page .activity-title,
body.spark-forum header .brand-title {
  overflow: hidden;
  color: var(--spark-text);
  font-size: clamp(1rem, 2vw, 1.18rem);
  font-weight: 800;
  letter-spacing: -.02em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.brand-kicker {
  display: block;
  margin-bottom: 1px;
  color: var(--spark-accent);
  font-size: .68rem;
  font-weight: 800;
  letter-spacing: .14em;
  line-height: 1.2;
  text-transform: uppercase;
}

.student-nav-actions,
body.spark-activity .auth {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
}

.student-nav-link,
.student-nav-button {
  display: inline-flex;
  min-height: 40px;
  padding: 8px 13px;
  align-items: center;
  justify-content: center;
  gap: 7px;
  border: 1px solid var(--spark-border);
  border-radius: 999px;
  color: var(--spark-text) !important;
  background: var(--spark-surface-solid);
  cursor: pointer;
  text-decoration: none;
  font-size: .82rem;
  font-weight: 700;
  line-height: 1;
}

.student-nav-link:hover,
.student-nav-button:hover {
  color: var(--spark-accent) !important;
  border-color: var(--spark-accent);
  background: var(--spark-accent-soft);
}

.student-nav-button.is-danger,
body.spark-activity #signoutBtn {
  color: var(--spark-danger) !important;
}

.student-nav-actions span {
  color: inherit !important;
  font: inherit !important;
  letter-spacing: inherit !important;
}

.spark-theme-toggle {
  top: auto;
  right: 18px;
  bottom: 18px;
  background: color-mix(in srgb, var(--spark-surface-solid) 92%, transparent);
}

/* ---------------- Home / discovery landing ---------------- */

body.spark-home > header {
  position: sticky;
  top: 0;
}

body.spark-home .rightBox {
  max-width: 720px;
  margin-left: auto;
  padding-right: 0;
}

body.spark-home .meta {
  display: none;
}

body.spark-home main {
  display: block;
  width: min(var(--spark-content), calc(100% - 36px));
  margin: 26px auto 64px;
}

.home-hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(310px, .8fr);
  min-height: 450px;
  overflow: hidden;
  border: 1px solid color-mix(in srgb, var(--spark-accent) 20%, var(--spark-border));
  border-radius: var(--spark-radius-xl);
  color: #fff;
  background:
    radial-gradient(circle at 78% 22%, rgba(98, 232, 213, .28), transparent 18rem),
    radial-gradient(circle at 96% 100%, rgba(128, 166, 255, .32), transparent 23rem),
    linear-gradient(128deg, #081735 0%, #153f87 62%, #147fa0 120%);
  box-shadow: 0 28px 75px rgba(25, 60, 118, .22);
}

.home-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  opacity: .18;
  background-image:
    linear-gradient(rgba(255,255,255,.18) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.18) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: linear-gradient(90deg, transparent, #000 62%);
  pointer-events: none;
}

.home-hero__copy {
  position: relative;
  z-index: 2;
  display: flex;
  padding: clamp(34px, 5vw, 70px);
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
}

.home-eyebrow,
.section-eyebrow,
.forum-eyebrow,
.ai-eyebrow {
  display: inline-flex;
  margin: 0 0 14px;
  align-items: center;
  gap: 8px;
  color: #9ee9f5;
  font-size: .76rem;
  font-weight: 800;
  letter-spacing: .16em;
  text-transform: uppercase;
}

.home-eyebrow::before,
.section-eyebrow::before,
.forum-eyebrow::before,
.ai-eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  border-radius: 10px;
  background: currentColor;
}

.home-hero h1 {
  max-width: 760px;
  margin: 0;
  font-size: clamp(2.3rem, 6vw, 5.3rem);
  font-weight: 800;
  letter-spacing: -.055em;
  line-height: 1.04;
}

.home-hero h1 span {
  display: block;
  color: #72e1d2;
}

.home-hero__lead {
  max-width: 650px;
  margin: 24px 0 28px;
  color: #dceaff;
  font-size: clamp(1rem, 2vw, 1.16rem);
  line-height: 1.8;
}

.home-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.hero-action {
  display: inline-flex;
  min-height: 50px;
  padding: 11px 18px;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(255,255,255,.3);
  border-radius: 14px;
  color: #fff !important;
  background: rgba(255,255,255,.10);
  text-decoration: none;
  font-weight: 800;
}

.hero-action.primary {
  color: #073c42 !important;
  border-color: #72e1d2;
  background: #72e1d2;
}

.hero-action:hover { transform: translateY(-2px); background: rgba(255,255,255,.17); }
.hero-action.primary:hover { background: #93eee2; }

.home-hero__visual {
  position: relative;
  z-index: 2;
  display: grid;
  min-height: 430px;
  place-items: center;
}

.science-orbit {
  position: relative;
  width: min(360px, 80%);
  aspect-ratio: 1;
}

.science-orbit__core {
  position: absolute;
  z-index: 3;
  inset: 25%;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255,255,255,.28);
  border-radius: 34%;
  background: linear-gradient(145deg, rgba(255,255,255,.2), rgba(255,255,255,.07));
  box-shadow: inset 0 0 35px rgba(255,255,255,.12), 0 24px 55px rgba(0,0,0,.22);
  backdrop-filter: blur(12px);
  font-size: clamp(2.3rem, 6vw, 4.2rem);
  font-weight: 900;
  letter-spacing: -.08em;
}

.science-orbit__ring {
  position: absolute;
  inset: 9%;
  border: 1px solid rgba(255,255,255,.26);
  border-radius: 50%;
  animation: spark-spin 28s linear infinite;
}

.science-orbit__ring.ring-two {
  inset: 20% 1%;
  transform: rotate(58deg);
  animation-duration: 36s;
  animation-direction: reverse;
}

.science-orbit__node {
  position: absolute;
  display: grid;
  width: 58px;
  height: 58px;
  place-items: center;
  border: 1px solid rgba(255,255,255,.3);
  border-radius: 18px;
  background: rgba(6, 25, 56, .65);
  box-shadow: 0 14px 34px rgba(0,0,0,.22);
  backdrop-filter: blur(8px);
  font-size: 1.25rem;
  font-weight: 900;
}

.science-orbit__node.n1 { top: 1%; left: 43%; }
.science-orbit__node.n2 { top: 44%; right: -1%; }
.science-orbit__node.n3 { right: 17%; bottom: 4%; }
.science-orbit__node.n4 { bottom: 8%; left: 10%; }
.science-orbit__node.n5 { top: 35%; left: -2%; }

@keyframes spark-spin { to { transform: rotate(360deg); } }

.home-section-heading {
  display: flex;
  margin: 48px 0 18px;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
}

.home-section-heading h2 {
  margin: 0;
  color: var(--spark-text);
  font-size: clamp(1.7rem, 3.5vw, 2.6rem);
  letter-spacing: -.035em;
}

.home-section-heading p { max-width: 560px; margin: 0; color: var(--spark-text-soft); text-align: right; }
.section-eyebrow { margin-bottom: 6px; color: var(--spark-accent); }

body.spark-home #activityGrid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 18px;
}

body.spark-home #activityGrid .card {
  grid-column: span 4;
  min-height: 390px;
  border: 1px solid var(--spark-border);
  border-radius: 24px;
  background: var(--spark-surface-solid);
  box-shadow: var(--spark-shadow-soft);
}

body.spark-home #activityGrid .card:nth-child(1),
body.spark-home #activityGrid .card:nth-child(5n) {
  grid-column: span 6;
}

body.spark-home #activityGrid .card:hover {
  transform: translateY(-7px);
  box-shadow: var(--spark-shadow);
}

.activity-card-media {
  position: relative;
  height: 238px;
  overflow: hidden;
}

body.spark-home .card img {
  height: 100%;
  border: 0;
  transition: transform .45s ease;
}

body.spark-home .card:hover img { transform: scale(1.045); }

.activity-kind {
  position: absolute;
  top: 15px;
  left: 15px;
  padding: 6px 10px;
  border: 1px solid rgba(255,255,255,.35);
  border-radius: 999px;
  color: #fff;
  background: rgba(6, 22, 48, .72);
  backdrop-filter: blur(9px);
  font-size: .72rem;
  font-weight: 800;
}

body.spark-home .card-content {
  display: grid;
  min-height: 150px;
  padding: 22px;
  align-content: space-between;
  gap: 12px;
}

body.spark-home .card-content h2 {
  margin: 0;
  color: var(--spark-text);
  font-size: 1.3rem;
  line-height: 1.45;
  text-align: left;
}

.activity-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--spark-text-soft);
  font-size: .8rem;
}

.activity-card-footer strong { color: var(--spark-accent); }

body.spark-home .info {
  margin: 22px 0 0;
  padding: 0;
  border-radius: 18px;
  background: color-mix(in srgb, var(--spark-surface-solid) 82%, transparent);
  box-shadow: none;
}

body.spark-home .info::before { content: none; }
body.spark-home .info summary { padding: 15px 18px; color: var(--spark-text); cursor: pointer; font-weight: 800; }
body.spark-home .info-body { padding: 0 18px 18px; color: var(--spark-text-soft); }

body.spark-home footer {
  border-top: 1px solid var(--spark-border);
  background: var(--spark-surface-solid);
}

/* ---------------- Activity / mission workspace ---------------- */

body.spark-activity > header { position: sticky; top: 0; }
body.spark-activity .auth { margin-left: auto; padding-right: 0; }
body.spark-activity #authStat { max-width: 280px; overflow: hidden; color: var(--spark-text-soft); font-size: .78rem; text-overflow: ellipsis; white-space: nowrap; }

body.spark-activity .intro-container {
  display: grid;
  grid-template-columns: minmax(320px, 1.05fr) minmax(340px, .95fr);
  width: min(1180px, calc(100% - 36px));
  max-width: none;
  min-height: 560px;
  margin: 34px auto 64px;
  padding: 0;
  overflow: hidden;
  border-radius: 30px;
  text-align: left;
}

.activity-intro-media { position: relative; min-height: 500px; overflow: hidden; background: var(--spark-surface-soft); }
body.spark-activity .intro-container .activity-intro-media img { width: 100%; height: 100%; margin: 0; border-radius: 0; object-fit: cover; box-shadow: none; }
.activity-intro-media::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 45%, rgba(4, 16, 37, .62)); }
.activity-intro-label { position: absolute; z-index: 2; left: 24px; bottom: 22px; padding: 7px 11px; border: 1px solid rgba(255,255,255,.3); border-radius: 999px; color: #fff; background: rgba(4,16,37,.56); backdrop-filter: blur(8px); font-size: .76rem; font-weight: 800; }
.activity-intro-copy { display: flex; padding: clamp(32px, 5vw, 64px); flex-direction: column; align-items: flex-start; justify-content: center; }
body.spark-activity .intro-container h1 { margin: 0 0 18px; color: var(--spark-text); font-size: clamp(2rem, 5vw, 3.7rem); letter-spacing: -.045em; line-height: 1.12; }
body.spark-activity .intro-container p { margin: 0 0 30px; color: var(--spark-text-soft); font-size: 1rem; line-height: 1.85; }
.activity-intro-actions { display: flex; flex-wrap: wrap; gap: 10px; }

body.spark-activity .page {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  width: min(1540px, calc(100% - 32px));
  min-height: 0;
  height: auto;
  margin: 20px auto 54px;
  gap: 18px;
  align-items: start;
}

body.spark-activity .page > .card { min-height: 0; border-radius: 24px; }
body.spark-activity .page > .card:nth-child(1) { grid-column: 1 / -1; }
body.spark-activity .page > .card:nth-child(2) { grid-column: span 7; min-height: 780px; }
body.spark-activity .page > .card:nth-child(3) { grid-column: span 5; min-height: 780px; }

body.spark-activity .card .head {
  position: relative;
  padding: 18px 22px 14px;
  border: 0;
  color: var(--spark-text);
  background: transparent;
  font-size: 1rem;
  font-weight: 800;
}

body.spark-activity .card .head::before {
  display: block;
  margin-bottom: 2px;
  color: var(--spark-accent);
  font-size: .66rem;
  font-weight: 800;
  letter-spacing: .14em;
  text-transform: uppercase;
}

body.spark-activity .page > .card:nth-child(1) .head::before { content: "LEARNING PATH"; }
body.spark-activity .page > .card:nth-child(2) .head::before { content: "EVIDENCE & CONTEXT"; }
body.spark-activity .page > .card:nth-child(3) .head::before { content: "YOUR RESPONSE"; }
body.spark-activity .card .body { padding: 8px 22px 24px; overflow: visible; }

body.spark-activity .page > .activity-path-card {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  padding: 8px 10px;
  align-items: center;
  overflow: visible;
}

body.spark-activity .activity-path-card > .head {
  min-width: 130px;
  padding: 10px 16px;
}

.activity-path-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  min-width: 0;
  align-items: center;
  gap: 12px;
}

body.spark-activity .activity-stepper-body {
  min-width: 0;
  padding: 4px 0;
  overflow: hidden;
}

body.spark-activity .stepper {
  display: flex;
  padding: 4px 0 3px;
  flex-direction: row;
  gap: 9px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
}

body.spark-activity .chip {
  display: inline-flex;
  width: auto;
  min-width: 180px;
  min-height: 56px;
  padding: 9px 13px;
  flex: 1 0 180px;
  align-items: center;
  gap: 10px;
  border-radius: 14px;
  scroll-snap-align: start;
}

.activity-quick-tools {
  display: flex;
  padding: 3px 0;
  align-items: stretch;
  gap: 8px;
}

.activity-tool-button {
  display: inline-flex;
  min-width: 132px;
  min-height: 56px;
  padding: 8px 12px;
  align-items: center;
  gap: 9px;
  border: 1px solid var(--spark-border);
  border-radius: 14px;
  color: var(--spark-text);
  background: var(--spark-surface-solid);
  box-shadow: var(--spark-shadow-soft);
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: transform .16s ease, border-color .16s ease, background .16s ease;
}

.activity-tool-button:hover:not(:disabled) { transform: translateY(-2px); border-color: var(--spark-accent); }
.activity-tool-button > span:first-child { display: grid; width: 32px; height: 32px; flex: 0 0 auto; place-items: center; border-radius: 10px; color: var(--spark-accent-contrast); background: var(--spark-accent); font-size: 1rem; }
.activity-tool-button > span:last-child { display: flex; flex-direction: column; line-height: 1.25; }
.activity-tool-button small { color: var(--spark-text-soft); font-size: .61rem; font-weight: 700; }
.activity-tool-button strong { color: var(--spark-text); font-size: .78rem; white-space: nowrap; }
.activity-tool-button.is-ai { background: linear-gradient(145deg, var(--spark-secondary-soft), var(--spark-surface-solid)); }
.activity-tool-button.is-ai > span:first-child { background: var(--spark-secondary); }
.activity-tool-button.is-note { background: linear-gradient(145deg, var(--spark-accent-soft), var(--spark-surface-solid)); }
.activity-tool-button:disabled { opacity: .46; cursor: wait; }

.step-number { display: grid; width: 30px; height: 30px; flex: 0 0 auto; place-items: center; border: 1px solid var(--spark-border); border-radius: 10px; background: var(--spark-surface-soft); font-size: .78rem; font-weight: 900; }
.chip.active .step-number { color: var(--spark-accent); border-color: color-mix(in srgb, var(--spark-accent-contrast) 45%, transparent); background: color-mix(in srgb, var(--spark-accent-contrast) 88%, transparent); }
.step-label { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

body.spark-activity .rich-text-content { color: var(--spark-text); font-size: 1.02rem; line-height: 1.9; }
body.spark-activity .rich-text-content img,
body.spark-activity .rich-text-content video { width: 100%; border-radius: 18px; box-shadow: var(--spark-shadow-soft); }
body.spark-activity .question-block { padding: 4px 0 20px; }
body.spark-activity .qtitle { color: var(--spark-text); font-size: 1.1rem; line-height: 1.65; }
body.spark-activity .inputbox textarea { min-height: 150px; padding: 15px; border-radius: 15px; background: var(--spark-surface-solid); }
body.spark-activity .choice-btn,
body.spark-activity .choice-label,
body.spark-activity .ordering-item,
body.spark-activity .matching-item { padding: 13px 15px; border-radius: 14px; }
body.spark-activity .footnav { position: sticky; bottom: 0; z-index: 4; margin: 22px -6px 0; padding: 14px 6px 3px; background: linear-gradient(180deg, transparent, var(--spark-surface-solid) 28%); }
body.spark-activity .iframe-box-fill {
  width: 100%;
  height: clamp(720px, calc(100dvh - 225px), 960px);
  min-height: 720px;
  overflow: hidden;
  border-radius: 16px;
  background: var(--spark-surface-solid);
}
body.spark-activity .iframe-box-fill iframe { display: block; width: 100% !important; height: 100% !important; min-height: 720px; }

/* ---------------- AI learning coach ---------------- */

body.spark-ai {
  display: block;
  height: auto;
  min-height: 100dvh;
  padding: 14px;
}

body.spark-ai .modal {
  display: grid;
  grid-template-columns: minmax(250px, .72fr) minmax(0, 1.65fr);
  grid-template-rows: auto minmax(0, 1fr);
  grid-template-areas: "top top" "character conversation";
  width: min(1220px, 100%);
  height: calc(100dvh - 28px);
  max-height: none;
  padding: 0;
  overflow: hidden;
  gap: 0;
  border-radius: 28px;
}

.ai-topbar {
  grid-area: top;
  display: flex;
  min-height: 72px;
  padding: 11px 18px;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  border-bottom: 1px solid var(--spark-border);
  background: color-mix(in srgb, var(--spark-surface-solid) 92%, transparent);
}

.ai-topbar__title strong { display: block; color: var(--spark-text); font-size: .98rem; }
.ai-topbar__title span { display: block; margin-top: 2px; color: var(--spark-text-soft); font-size: .72rem; }
.ai-topbar .student-nav-actions { margin-left: auto; }

body.spark-ai .left {
  grid-area: character;
  position: relative;
  min-height: 0;
  padding: 32px 20px 22px;
  overflow: hidden;
  border: 0;
  border-right: 1px solid var(--spark-border);
  border-radius: 0;
  background:
    radial-gradient(circle at 50% 22%, var(--spark-glow-b), transparent 14rem),
    linear-gradient(160deg, var(--spark-surface-soft), var(--spark-surface-solid));
}

body.spark-ai .left::before { content: "AI LEARNING COACH"; position: absolute; top: 18px; left: 20px; color: var(--spark-accent); font-size: .65rem; font-weight: 900; letter-spacing: .14em; }
body.spark-ai .left img { width: min(100%, 340px); max-height: min(58dvh, 500px); margin-top: 18px; object-fit: contain; }
body.spark-ai .left h3 { margin: 12px 0 5px; color: var(--spark-text); font-size: 1.5rem; }
.ai-character-placeholder { display: grid; height: 100%; padding: 30px; place-items: center; color: var(--spark-text-soft); text-align: center; }
.ai-character-placeholder__orb { display: grid; width: 120px; height: 120px; margin: 0 auto 18px; place-items: center; border: 1px solid var(--spark-border); border-radius: 38%; color: var(--spark-accent); background: var(--spark-accent-soft); font-size: 2.8rem; box-shadow: var(--spark-shadow-soft); }

body.spark-ai .right {
  grid-area: conversation;
  display: grid;
  grid-template-rows: auto auto minmax(180px, 1fr) auto;
  min-height: 0;
  padding: 22px;
  gap: 13px;
}

.ai-conversation-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 14px; }
.ai-conversation-head h1 { margin: 0; color: var(--spark-text); font-size: clamp(1.35rem, 3vw, 2rem); letter-spacing: -.035em; }
.ai-conversation-head p { margin: 4px 0 0; color: var(--spark-text-soft); font-size: .82rem; }
.ai-eyebrow { margin-bottom: 4px; color: var(--spark-accent); }

body.spark-ai .roles { display: grid; grid-template-columns: repeat(auto-fit, minmax(128px, 1fr)); gap: 9px; }
body.spark-ai .role { min-height: 65px; padding: 10px 12px; border-radius: 15px; text-align: left; }
body.spark-ai .role strong { display: block; color: var(--spark-text); font-size: .9rem; }
body.spark-ai .role.active { border-color: var(--spark-accent); background: var(--spark-accent-soft); box-shadow: inset 4px 0 0 var(--spark-accent); }
body.spark-ai .role .badge { display: inline-flex; margin-top: 5px; }
body.spark-ai .log { min-height: 0; margin: 0; padding: 18px; border-radius: 19px; }
body.spark-ai .msg { padding: 12px 15px; border-radius: 16px; animation: message-in .22s ease both; }
body.spark-ai .msg.user { margin-left: auto; border-bottom-right-radius: 5px; }
body.spark-ai .msg.ai { margin-right: auto; border-bottom-left-radius: 5px; box-shadow: 0 6px 18px color-mix(in srgb, var(--spark-text) 6%, transparent); }
@keyframes message-in { from { opacity: 0; transform: translateY(7px); } }
body.spark-ai .input { display: grid; grid-template-columns: minmax(0,1fr) auto; margin: 0; gap: 9px; }
body.spark-ai textarea { min-height: 72px; padding: 14px 15px; border-radius: 16px; }
body.spark-ai #send { min-width: 82px; border-radius: 16px; font-weight: 800; }
body.spark-ai .spark-theme-toggle { bottom: 20px; }

/* ---------------- Public hearing simulation ---------------- */

body.spark-forum > header {
  position: sticky;
  top: 0;
  justify-content: space-between;
}

body.spark-forum .banner {
  position: relative;
  padding: clamp(38px, 6vw, 72px) max(20px, calc((100vw - var(--spark-content)) / 2));
  overflow: hidden;
  border-bottom: 1px solid var(--spark-border);
  background:
    radial-gradient(circle at 85% 20%, var(--spark-glow-b), transparent 24rem),
    linear-gradient(125deg, color-mix(in srgb, var(--spark-accent-soft) 85%, var(--spark-surface-solid)), var(--spark-surface-soft));
}

body.spark-forum .banner::after { content: "PUBLIC HEARING"; position: absolute; right: 4%; bottom: -25px; color: color-mix(in srgb, var(--spark-accent) 8%, transparent); font-size: clamp(4rem, 10vw, 9rem); font-weight: 900; letter-spacing: -.06em; pointer-events: none; }
.forum-banner-inner { position: relative; z-index: 2; display: grid; grid-template-columns: minmax(0,1fr) minmax(260px,.45fr); width: min(var(--spark-content), 100%); margin: 0 auto; align-items: end; gap: 30px; }
.forum-eyebrow { margin-bottom: 8px; color: var(--spark-accent); }
body.spark-forum .banner h1 { max-width: 850px; margin: 0 0 12px; color: var(--spark-text); font-size: clamp(2rem, 5vw, 4.5rem); line-height: 1.08; }
body.spark-forum .banner p { color: var(--spark-text-soft); }
.forum-brief { padding: 17px 18px; border: 1px solid var(--spark-border); border-radius: 17px; background: color-mix(in srgb, var(--spark-surface-solid) 78%, transparent); box-shadow: var(--spark-shadow-soft); }
.forum-brief strong { display: block; margin-bottom: 5px; color: var(--spark-accent); }
.forum-brief span { color: var(--spark-text-soft); font-size: .82rem; line-height: 1.6; }

body.spark-forum .container {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  grid-template-areas: "roles stage" "roles record";
  width: min(var(--spark-content), calc(100% - 32px));
  margin: 0 auto;
  padding: 24px 0 56px;
  align-items: start;
  gap: 18px;
}

body.spark-forum .sidebar { grid-area: roles; position: sticky; top: calc(var(--spark-header-height) + 18px); padding: 16px; }
body.spark-forum .sidebar::before { content: "參與角色"; display: block; margin: 2px 2px 13px; color: var(--spark-text); font-size: 1rem; font-weight: 800; }
body.spark-forum .main { grid-area: stage; min-height: 420px; padding: clamp(20px, 3vw, 34px); }
body.spark-forum .log { grid-area: record; min-height: 220px; max-height: none; padding: clamp(20px, 3vw, 30px); overflow: visible; }
body.spark-forum .log > h3 { margin: 0 0 16px; color: var(--spark-text); font-size: 1.18rem; }
body.spark-forum .role-btn { position: relative; min-height: 62px; padding: 12px 13px 12px 45px; border-left: 0; border-radius: 15px; }
body.spark-forum .role-btn::before { content: attr(data-index); position: absolute; left: 11px; top: 50%; display: grid; width: 25px; height: 25px; place-items: center; transform: translateY(-50%); border-radius: 9px; color: var(--spark-accent); background: var(--spark-accent-soft); font-size: .72rem; font-weight: 900; }
body.spark-forum .role-btn.done::after { content: "完成"; display: block; margin-top: 2px; color: var(--spark-secondary); font-size: .68rem; }
body.spark-forum .avatar { align-items: center; margin-bottom: 18px; }
body.spark-forum .avatar h3 { margin: 0; color: var(--spark-text); font-size: 1.45rem; }
body.spark-forum .avatar-art { width: 64px; height: 64px; }
.forum-empty { display: flex; min-height: 350px; padding: 30px; flex-direction: column; align-items: center; justify-content: center; color: var(--spark-text-soft); text-align: center; }
.forum-empty__icon { display: grid; width: 74px; height: 74px; margin-bottom: 18px; place-items: center; border: 1px solid var(--spark-border); border-radius: 24px; color: var(--spark-accent); background: var(--spark-accent-soft); box-shadow: var(--spark-shadow-soft); font-size: 1.6rem; font-weight: 900; }
.forum-empty .section-eyebrow { margin-bottom: 5px; }
.forum-empty h2 { margin: 0 0 8px; color: var(--spark-text); font-size: clamp(1.5rem, 3vw, 2.25rem); }
.forum-empty p { max-width: 560px; }
.forum-complete .forum-empty__icon { color: var(--spark-secondary); background: var(--spark-secondary-soft); }
body.spark-forum .utterance { padding: 15px 17px; border-radius: 15px; line-height: 1.85; }
body.spark-forum .utterance::after { content: "點選此段提出質詢"; display: block; margin-top: 7px; color: var(--spark-accent); font-size: .7rem; font-weight: 800; opacity: 0; transition: opacity .16s; }
body.spark-forum .utterance:hover::after { opacity: 1; }
body.spark-forum .arg-btn,
body.spark-forum .action { min-height: 43px; padding: 9px 14px; border-radius: 13px; }
body.spark-forum blockquote { padding: 15px 17px; border-radius: 13px; color: var(--spark-text); background: var(--spark-accent-soft); }
body.spark-forum textarea { min-height: 140px; height: auto; padding: 14px; border-radius: 15px; }
body.spark-forum .log-item { padding: 17px; border: 1px solid var(--spark-border); border-radius: 16px; background: var(--spark-surface-solid); }
body.spark-forum .log-item h4 { color: var(--spark-accent); }
body.spark-forum .log-item [id^="reply-"] > div { color: var(--spark-text-soft) !important; }

/* ---------------- AI records / learning portfolio ---------------- */

body.spark-records > header {
  position: sticky;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.records-title {
  display: flex;
  align-items: center;
  gap: 12px;
}

.records-title strong { display: block; color: var(--spark-text); font-size: 1.05rem; }
.records-icon { display: grid; width: 44px; height: 44px; place-items: center; border-radius: 14px; color: var(--spark-accent-contrast); background: linear-gradient(145deg, var(--spark-accent), var(--spark-secondary)); font-size: 1.25rem; }
.records-auth-stat { max-width: 180px; overflow: hidden; color: var(--spark-text-soft); font-size: .78rem; text-overflow: ellipsis; white-space: nowrap; }
.sr-only { position: absolute !important; width: 1px !important; height: 1px !important; padding: 0 !important; overflow: hidden !important; clip: rect(0, 0, 0, 0) !important; white-space: nowrap !important; border: 0 !important; }

.records-context-bar {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(260px, .7fr);
  width: min(1320px, calc(100% - 36px));
  margin: 28px auto 0;
  padding: clamp(22px, 3vw, 34px);
  align-items: end;
  gap: 18px;
  border: 1px solid var(--spark-border);
  border-radius: 25px;
  background:
    radial-gradient(circle at 90% 10%, var(--spark-secondary-soft), transparent 18rem),
    linear-gradient(135deg, var(--spark-surface), var(--spark-surface-solid));
  box-shadow: var(--spark-shadow-soft);
}
.records-context-bar .section-eyebrow { margin: 0 0 5px; }
.records-context-bar h1 { margin: 0; color: var(--spark-text); font-size: clamp(1.55rem, 3vw, 2.45rem); line-height: 1.25; }
.records-context-bar > div > p:last-child { max-width: 760px; margin: 10px 0 0; color: var(--spark-text-soft); line-height: 1.7; }
.records-context-note { display: flex; padding: 15px 17px; flex-direction: column; border: 1px solid color-mix(in srgb, var(--spark-secondary) 35%, var(--spark-border)); border-radius: 16px; background: var(--spark-secondary-soft); }
.records-context-note strong { color: var(--spark-text); font-size: .88rem; }
.records-context-note span { margin-top: 4px; color: var(--spark-text-soft); font-size: .76rem; line-height: 1.55; }

body.spark-records main.records-workspace {
  display: grid;
  grid-template-columns: minmax(360px, .9fr) minmax(0, 1.25fr);
  width: min(1320px, calc(100% - 36px));
  height: min(720px, calc(100dvh - var(--spark-header-height) - 205px));
  min-height: 560px;
  margin: 18px auto 32px;
  gap: 18px;
}

body.spark-records .records-sources,
body.spark-records .records-editor {
  min-width: 0;
  padding: 0;
  overflow: hidden;
  border: 1px solid var(--spark-border);
  border-radius: 22px;
  background: var(--spark-surface);
  box-shadow: var(--spark-shadow-soft);
}

body.spark-records .records-sources { display: grid; grid-template-rows: auto auto minmax(0, 1fr); }
body.spark-records .records-editor { display: grid; grid-template-rows: auto auto minmax(0, 1fr); }

.records-panel-head { display: flex; min-height: 70px; padding: 16px 20px; flex-direction: column; justify-content: center; border-bottom: 1px solid var(--spark-border); background: var(--spark-surface-soft); }
.records-panel-head span { color: var(--spark-text); font-weight: 800; }
.records-panel-head small { margin-top: 2px; color: var(--spark-text-soft); }
.records-source-tabs { display: grid; grid-template-columns: repeat(3, 1fr); gap: 7px; padding: 10px; border-bottom: 1px solid var(--spark-border); background: var(--spark-surface-solid); }
.records-source-tabs button { min-height: 40px; padding: 8px 9px; border: 1px solid transparent; border-radius: 11px; color: var(--spark-text-soft); background: transparent; font: inherit; font-size: .8rem; font-weight: 800; cursor: pointer; }
.records-source-tabs button:hover { color: var(--spark-accent); background: var(--spark-accent-soft); }
.records-source-tabs button.is-active { color: var(--spark-accent-contrast); background: var(--spark-accent); box-shadow: 0 7px 18px color-mix(in srgb, var(--spark-accent) 26%, transparent); }
.records-source-panels { min-height: 0; overflow: hidden; }
.records-source-panel { height: 100%; padding: 14px; overflow-y: auto; }
.records-source-panel[hidden] { display: none; }
.records-loading { padding: 50px 12px; color: var(--spark-text-soft); text-align: center; }
.records-source-card { padding: 15px; border: 1px solid var(--spark-border); border-radius: 16px; background: var(--spark-surface-solid); box-shadow: 0 6px 18px color-mix(in srgb, var(--spark-text) 7%, transparent); }
.records-source-card + .records-source-card { margin-top: 11px; }
.records-source-card__head { display: flex; align-items: flex-start; justify-content: space-between; gap: 10px; }
.records-source-card__head small { color: var(--spark-accent); font-size: .67rem; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.records-source-card__head h2 { margin: 3px 0 0; color: var(--spark-text); font-size: .94rem; line-height: 1.45; }
.records-source-card__meta { flex: 0 0 auto; padding: 4px 7px; border-radius: 999px; color: var(--spark-secondary); background: var(--spark-secondary-soft); font-size: .64rem; font-weight: 800; }
.records-source-card__content { display: -webkit-box; margin: 11px 0 12px; overflow: hidden; color: var(--spark-text-soft); font-size: .82rem; line-height: 1.75; -webkit-box-orient: vertical; -webkit-line-clamp: 6; white-space: pre-line; }
.records-add-button { min-height: 35px; padding: 7px 10px; border: 1px solid var(--spark-border); border-radius: 10px; color: var(--spark-accent); background: var(--spark-accent-soft); font: inherit; font-size: .72rem; font-weight: 850; cursor: pointer; }
.records-add-button:hover { color: var(--spark-accent-contrast); border-color: var(--spark-accent); background: var(--spark-accent); }
.records-add-button:disabled { opacity: .46; cursor: wait; }
.records-empty { display: flex; min-height: 300px; padding: 26px; flex-direction: column; align-items: center; justify-content: center; color: var(--spark-text-soft); text-align: center; }
.records-empty > span { display: grid; width: 56px; height: 56px; margin-bottom: 13px; place-items: center; border-radius: 17px; color: var(--spark-accent); background: var(--spark-accent-soft); font-size: 1.35rem; }
.records-empty strong { color: var(--spark-text); }
.records-empty p { max-width: 300px; margin: 5px 0 0; font-size: .8rem; line-height: 1.6; }

.records-editor-head { display: flex; min-height: 70px; padding: 15px 19px; align-items: center; justify-content: space-between; gap: 12px; border-bottom: 1px solid var(--spark-border); background: var(--spark-surface-soft); }
.records-editor-head > div { display: flex; min-width: 0; flex-direction: column; }
.records-editor-head span:first-child { color: var(--spark-text); font-weight: 850; }
.records-editor-head small { margin-top: 2px; color: var(--spark-text-soft); }
.records-save-status { flex: 0 0 auto; padding: 5px 9px; border-radius: 999px; color: var(--spark-text-soft); background: var(--spark-surface-solid); font-size: .68rem; font-weight: 800; }
.records-save-status.is-saved { color: var(--spark-secondary); background: var(--spark-secondary-soft); }
.records-save-status.is-error { color: var(--spark-danger); background: color-mix(in srgb, var(--spark-danger) 12%, transparent); }
.records-toolbar { display: flex; min-height: 54px; padding: 9px 13px; align-items: center; justify-content: space-between; gap: 12px; border-bottom: 1px solid var(--spark-border); background: var(--spark-surface-solid); }
.records-toolbar > span { color: var(--spark-text-soft); font-size: .72rem; line-height: 1.5; }
.records-toolbar > div { display: flex; flex: 0 0 auto; gap: 6px; }
.records-toolbar button { min-height: 32px; padding: 6px 9px; border: 1px solid var(--spark-border); border-radius: 9px; color: var(--spark-text); background: transparent; font: inherit; font-size: .7rem; font-weight: 800; cursor: pointer; }
.records-toolbar button:hover { color: var(--spark-accent); border-color: var(--spark-accent); }
.records-toolbar button.is-danger { color: var(--spark-danger); }
body.spark-records #note { width: 100%; height: 100%; min-height: 0; padding: clamp(18px, 3vw, 30px); resize: none; border: 0; outline: 0; color: var(--spark-text); background:
  linear-gradient(90deg, transparent 0 47px, color-mix(in srgb, var(--spark-accent) 15%, transparent) 47px 48px, transparent 48px),
  repeating-linear-gradient(180deg, transparent 0 31px, color-mix(in srgb, var(--spark-border) 52%, transparent) 31px 32px);
  font: 500 .98rem/2rem var(--spark-font-ui); caret-color: var(--spark-accent); }
body.spark-records #note::placeholder { color: var(--spark-text-soft); }
body.spark-records #note:disabled { opacity: .7; cursor: wait; }

/* Theme-specific personality without changing page structure. */
:root[data-spark-theme="midnight"] .home-hero {
  background:
    radial-gradient(circle at 78% 22%, rgba(56,189,248,.22), transparent 18rem),
    radial-gradient(circle at 96% 100%, rgba(167,139,250,.24), transparent 23rem),
    linear-gradient(128deg, #030916 0%, #102947 62%, #203560 120%);
}

:root[data-spark-theme="notebook"] .home-hero {
  background:
    radial-gradient(circle at 82% 18%, rgba(255,210,111,.22), transparent 18rem),
    linear-gradient(128deg, #382419 0%, #7d3b12 65%, #536c38 125%);
}

:root[data-spark-theme="focus"] .home-hero {
  border: 3px solid #111827;
  border-radius: 10px;
  background: linear-gradient(125deg, #111827 0%, #003f8f 100%);
  box-shadow: none;
}

:root[data-spark-theme="focus"] .home-hero::after,
:root[data-spark-theme="focus"] .science-orbit__ring,
:root[data-spark-theme="focus"] .banner::after {
  display: none;
}

:root[data-spark-theme="focus"] body.spark-student-page .card,
:root[data-spark-theme="focus"] body.spark-student-page .sidebar,
:root[data-spark-theme="focus"] body.spark-student-page .main,
:root[data-spark-theme="focus"] body.spark-student-page .log,
:root[data-spark-theme="focus"] body.spark-student-page .note {
  border-width: 2px;
  border-radius: 10px;
}

/* ---------------- Responsive ---------------- */

@media (max-width: 1050px) {
  body.spark-home #activityGrid .card,
  body.spark-home #activityGrid .card:nth-child(1),
  body.spark-home #activityGrid .card:nth-child(5n) { grid-column: span 6; }
  body.spark-activity .page > .card:nth-child(2),
  body.spark-activity .page > .card:nth-child(3) { grid-column: 1 / -1; min-height: 0; }
  body.spark-forum .container { grid-template-columns: 220px minmax(0,1fr); }
}

@media (max-width: 820px) {
  :root { --spark-header-height: 68px; }
  body.spark-student-page > header { flex-wrap: wrap; }
  body.spark-student-page > header img { width: 44px; height: 44px; border-radius: 13px; }
  .home-hero { grid-template-columns: 1fr; min-height: 0; }
  .home-hero__visual { min-height: 320px; }
  .science-orbit { width: min(300px, 72vw); }
  .home-section-heading { display: block; }
  .home-section-heading p { margin-top: 8px; text-align: left; }
  body.spark-activity .intro-container { grid-template-columns: 1fr; }
  .activity-intro-media { min-height: 320px; }
  body.spark-ai .modal { grid-template-columns: 1fr; grid-template-rows: auto auto minmax(0,1fr); grid-template-areas: "top" "character" "conversation"; overflow: auto; }
  body.spark-ai .left { min-height: 230px; padding: 20px; border-right: 0; border-bottom: 1px solid var(--spark-border); }
  body.spark-ai .left img { width: 180px; max-height: 180px; }
  body.spark-ai .left::before { display: none; }
  body.spark-ai .right { min-height: 520px; }
  .forum-banner-inner { grid-template-columns: 1fr; }
  body.spark-forum .container { grid-template-columns: 1fr; grid-template-areas: "roles" "stage" "record"; }
  body.spark-forum .sidebar { position: static; }
  body.spark-forum .sidebar { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
  body.spark-forum .sidebar::before { grid-column: 1/-1; }
  body.spark-forum .role-btn { margin: 0; }
}

@media (max-width: 620px) {
  body.spark-student-page > header { padding: 8px 11px; }
  .brand-kicker { display: none; }
  body.spark-home .rightBox { width: 100%; align-items: flex-start; }
  body.spark-home .auth { width: 100%; justify-content: space-between; }
  body.spark-home #authStat { max-width: 46vw; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .home-hero__copy { padding: 34px 24px; }
  .home-hero__visual { display: none; }
  body.spark-home #activityGrid .card,
  body.spark-home #activityGrid .card:nth-child(1),
  body.spark-home #activityGrid .card:nth-child(5n) { grid-column: 1 / -1; }
  body.spark-home #activityGrid .card { min-height: 340px; }
  .activity-card-media { height: 205px; }
  body.spark-activity .auth { width: 100%; justify-content: flex-start; }
  body.spark-activity #authStat { margin-right: auto; }
  body.spark-activity .page { width: min(100% - 18px, var(--spark-content)); }
  body.spark-activity .card .body { padding-inline: 15px; }
  body.spark-activity .page > .activity-path-card { grid-template-columns: 1fr; padding: 8px; }
  body.spark-activity .activity-path-card > .head { min-width: 0; padding: 8px 12px 3px; }
  body.spark-activity .activity-path-row { grid-template-columns: 1fr; gap: 7px; }
  body.spark-activity .activity-stepper-body { padding-inline: 4px; }
  body.spark-activity .activity-quick-tools { display: grid; grid-template-columns: repeat(2, 1fr); padding: 2px 4px 5px; }
  body.spark-activity .activity-tool-button { width: 100%; min-width: 0; }
  body.spark-activity .iframe-box-fill { height: 680px; min-height: 680px; }
  body.spark-activity .iframe-box-fill iframe { min-height: 680px; }
  body.spark-activity .matching-container { grid-template-columns: 1fr; }
  .ai-topbar { align-items: flex-start; }
  .ai-topbar__title span { display: none; }
  .ai-topbar .student-nav-link span,
  .ai-topbar .student-nav-button span { display: none; }
  body.spark-ai .right { padding: 14px; }
  body.spark-ai .roles { display: flex; overflow-x: auto; }
  body.spark-ai .role { min-width: 132px; }
  body.spark-ai .input { grid-template-columns: 1fr; }
  body.spark-ai #send { min-height: 48px; }
  body.spark-forum .sidebar { grid-template-columns: 1fr; }
  body.spark-records > header { position: relative; }
  body.spark-records .student-nav-actions { width: 100%; }
  .records-auth-stat { margin-right: auto; }
  .records-context-bar { grid-template-columns: 1fr; width: min(100% - 20px, 1320px); margin-top: 12px; padding: 20px; }
  body.spark-records main.records-workspace { grid-template-columns: 1fr; width: min(100% - 20px, 1320px); height: auto; min-height: 0; }
  body.spark-records .records-sources { min-height: 570px; }
  body.spark-records .records-editor { min-height: 620px; }
  .records-toolbar { align-items: flex-start; flex-direction: column; }
  .records-toolbar > div { width: 100%; }
  .records-toolbar button { flex: 1; }
}

@media (prefers-reduced-motion: reduce) {
  .science-orbit__ring { animation: none; }
  body.spark-ai .msg { animation: none; }
}