@import url('https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,200..900;1,9..144,200..900&family=IBM+Plex+Sans:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500;700&family=Noto+Sans+TC:wght@400;500;700&family=Noto+Serif+TC:wght@300;400;700&display=swap');

:root {
  --paper: #EFE6D2;
  --paper-2: #E5DBC3;
  --paper-3: #D9CDAF;
  --ink: #14110F;
  --ink-soft: #4A4239;
  --ink-muted: #8A7F71;
  --accent: #B8351F;
  --success: #2C6E3F;
  --warning: #A65A0F;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--paper);
  color: var(--ink);
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  font-size: 16px;
  line-height: 1.55;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* paper grain */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  opacity: 0.55;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0.08 0 0 0 0 0.07 0 0 0 0 0.06 0 0 0 0.22 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* warm vignette */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background: radial-gradient(ellipse at center, transparent 40%, rgba(20,17,15,0.08) 100%);
}

main { position: relative; z-index: 2; }

::selection { background: var(--ink); color: var(--paper); }

input:focus { outline: none; }

/* ==================== TYPOGRAPHY ==================== */
.serif { font-family: 'Fraunces', 'Noto Serif TC', serif; }
.mono { font-family: 'JetBrains Mono', monospace; }

h1, h2, h3 {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-variation-settings: 'opsz' 144;
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1;
}

.eyebrow {
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  font-size: 10.5px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.24em;
  color: var(--ink-soft);
}

.rule { height: 2px; background: var(--ink); border: 0; }
.rule-hair { height: 1px; background: var(--ink); opacity: 0.4; border: 0; }

.double-rule {
  border: 0;
  border-top: 2px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  height: 5px;
  margin: 24px 0;
}

@keyframes fade-up {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ==================== LANDING ==================== */
.landing {
  max-width: 960px;
  margin: 0 auto;
  padding: 48px 28px 64px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.masthead {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.masthead::before,
.masthead::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--ink);
  opacity: 0.5;
}
.masthead span { padding: 0 6px; }

.brand {
  text-align: center;
  padding: 56px 0 40px;
}
.brand .chinese {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-variation-settings: 'opsz' 144;
  font-weight: 300;
  font-style: italic;
  font-size: clamp(88px, 16vw, 184px);
  line-height: 0.92;
  letter-spacing: -0.045em;
  color: var(--ink);
  animation: fade-up 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) both;
  animation-delay: 0.05s;
}
.brand .english {
  font-family: 'Fraunces', serif;
  font-variation-settings: 'opsz' 144;
  font-weight: 300;
  font-style: italic;
  font-size: clamp(26px, 5vw, 52px);
  letter-spacing: -0.015em;
  margin-top: 6px;
  color: var(--ink-soft);
  animation: fade-up 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) both;
  animation-delay: 0.18s;
}
.brand .tagline {
  margin-top: 22px;
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-size: 17px;
  color: var(--ink-soft);
  animation: fade-up 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) both;
  animation-delay: 0.3s;
}

.role-grid {
  display: grid;
  grid-template-columns: 1fr 2px 1fr;
  gap: 0;
  margin-top: 32px;
  border-top: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
  animation: fade-up 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) both;
  animation-delay: 0.42s;
}
.role-grid .vertical-rule { background: var(--ink); width: 2px; }

.role-card {
  padding: 36px 32px;
  text-decoration: none;
  color: var(--ink);
  display: flex;
  flex-direction: column;
  transition: background 0.25s ease;
  position: relative;
}
.role-card:hover { background: var(--paper-2); }
.role-card .section-mark {
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-weight: 300;
  font-size: 13px;
  color: var(--ink-soft);
  margin-bottom: 20px;
  letter-spacing: 0.02em;
}
.role-card .role-title-cn {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-variation-settings: 'opsz' 144;
  font-weight: 400;
  font-size: 56px;
  line-height: 1;
  margin-bottom: 6px;
  letter-spacing: -0.02em;
}
.role-card .role-title-en {
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-weight: 300;
  font-size: 20px;
  color: var(--ink-soft);
  margin-bottom: 26px;
  letter-spacing: -0.01em;
}
.role-card ul { list-style: none; margin-bottom: 32px; }
.role-card li {
  font-size: 14px;
  color: var(--ink-soft);
  padding: 8px 0;
  border-bottom: 1px dotted var(--ink-muted);
  display: flex;
  align-items: center;
  gap: 10px;
}
.role-card li::before {
  content: '§';
  font-family: 'Fraunces', serif;
  font-style: italic;
  color: var(--ink);
  font-size: 14px;
}
.role-card .enter {
  margin-top: auto;
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-weight: 400;
  font-size: 22px;
  font-style: italic;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  letter-spacing: -0.01em;
  transition: gap 0.25s ease;
}
.role-card:hover .enter { gap: 22px; }
.enter .arrow {
  font-family: 'JetBrains Mono', monospace;
  font-style: normal;
  font-size: 22px;
  font-weight: 500;
}

.landing-footer {
  margin-top: auto;
  padding-top: 40px;
  text-align: center;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 10.5px;
  letter-spacing: 0.28em;
  color: var(--ink-muted);
  text-transform: uppercase;
}

/* ==================== PAGE SHELL ==================== */
.page {
  max-width: 1040px;
  margin: 0 auto;
  padding: 40px 28px 96px;
}
.page-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 14px;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 56px;
  gap: 16px;
}
.page-top .back {
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  font-size: 10.5px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.24em;
  color: var(--ink-soft);
  text-decoration: none;
  transition: color 0.15s;
}
.page-top .back:hover { color: var(--ink); }
.page-top .title {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-weight: 400;
  font-size: 19px;
  letter-spacing: -0.01em;
}
.page-top .meta {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10.5px;
  color: var(--ink-soft);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.panel { margin-bottom: 40px; }
.panel.hidden { display: none !important; }

/* ==================== BUTTONS ==================== */
.btn {
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.24em;
  background: var(--ink);
  color: var(--paper);
  border: 2px solid var(--ink);
  padding: 16px 26px;
  cursor: pointer;
  box-shadow: 6px 6px 0 var(--ink);
  transition: transform 0.12s ease, box-shadow 0.12s ease;
  display: inline-flex;
  align-items: center;
  gap: 14px;
}
.btn:hover:not(:disabled) {
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0 var(--ink);
}
.btn:active:not(:disabled) {
  transform: translate(6px, 6px);
  box-shadow: 0 0 0 var(--ink);
}
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn--lg { font-size: 13px; padding: 20px 32px; }
.btn--accent {
  background: var(--accent);
  border-color: var(--ink);
  color: var(--paper);
}
.btn .arrow {
  font-family: 'JetBrains Mono', monospace;
  font-size: 16px;
  letter-spacing: 0;
  transition: transform 0.2s;
}
.btn:hover:not(:disabled) .arrow { transform: translateX(3px); }

/* ==================== TEACHER: CREATE ==================== */
.create-panel { max-width: 720px; }
.create-panel .eyebrow { margin-bottom: 18px; }
.create-panel h1 {
  font-size: clamp(56px, 10vw, 124px);
  font-weight: 300;
  font-style: italic;
  line-height: 0.95;
  margin-bottom: 26px;
  letter-spacing: -0.03em;
}
.create-panel p {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-size: 19px;
  color: var(--ink-soft);
  margin-bottom: 40px;
  max-width: 560px;
  line-height: 1.45;
}

/* ==================== TEACHER: ROOM DISPLAY ==================== */
.room-display {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 48px;
  align-items: end;
  padding-bottom: 28px;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 14px;
}
.room-display .room-code-wrap .eyebrow { margin-bottom: 12px; }
.room-code-big {
  font-family: 'Fraunces', serif;
  font-variation-settings: 'opsz' 144;
  font-weight: 300;
  font-style: italic;
  font-size: clamp(104px, 20vw, 224px);
  line-height: 0.88;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.qr-frame {
  background: #fff;
  padding: 14px;
  border: 2px solid var(--ink);
  box-shadow: 8px 8px 0 var(--ink);
  line-height: 0;
  position: relative;
  margin-bottom: 28px;
}
.qr-frame::after {
  content: '— scan to join —';
  position: absolute;
  bottom: -28px;
  left: 0;
  right: 0;
  text-align: center;
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-size: 12px;
  color: var(--ink-soft);
  white-space: nowrap;
}

.room-meta { margin-bottom: 16px; }
.room-meta .eyebrow { margin-bottom: 6px; }
.room-meta .hint {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-size: 14px;
  color: var(--ink-soft);
  margin-top: 8px;
  max-width: 520px;
}
.join-url {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--ink);
  word-break: break-all;
  margin-top: 4px;
}

/* ==================== SECTION HEAD ==================== */
.section-head {
  display: flex;
  align-items: baseline;
  gap: 18px;
  margin: 48px 0 22px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--ink);
}
.section-head .num {
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-weight: 400;
  font-size: 26px;
  color: var(--ink-soft);
  letter-spacing: -0.02em;
}
.section-head h2 {
  font-size: 28px;
  font-weight: 400;
  font-style: italic;
  letter-spacing: -0.015em;
}
.section-head .section-meta {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 10px;
  color: var(--ink-soft);
  text-transform: uppercase;
  letter-spacing: 0.24em;
  font-weight: 600;
}
.section-head .section-meta .live-dot {
  width: 7px;
  height: 7px;
  background: var(--accent);
  border-radius: 50%;
  animation: pulse 1.6s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

/* ==================== TASK FORM ==================== */
.task-form {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 14px;
  align-items: stretch;
  margin-bottom: 20px;
}
.task-form input {
  width: 100%;
  background: var(--paper);
  border: 2px solid var(--ink);
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-weight: 400;
  font-size: 21px;
  padding: 16px 22px;
  color: var(--ink);
  box-shadow: 6px 6px 0 var(--ink);
  transition: transform 0.12s, box-shadow 0.12s;
  letter-spacing: -0.01em;
}
.task-form input:focus {
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0 var(--ink);
}
.task-form input::placeholder { color: var(--ink-muted); font-style: italic; }

.status-bar {
  display: flex;
  gap: 56px;
  padding: 20px 0 24px;
  border-bottom: 1px solid var(--ink);
  flex-wrap: wrap;
}
.stat-item { display: flex; flex-direction: column; gap: 4px; }
.stat-label {
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.stat-value {
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-weight: 400;
  font-size: 44px;
  line-height: 1;
  letter-spacing: -0.025em;
}

/* ==================== TASK LIST (TEACHER) ==================== */
.task-list { display: flex; flex-direction: column; }
.empty-state {
  padding: 56px 24px;
  text-align: center;
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-size: 20px;
  color: var(--ink-muted);
  border: 1px dashed var(--ink-muted);
  letter-spacing: -0.005em;
}

.task-card {
  padding: 28px 0;
  border-bottom: 1px solid var(--ink);
  display: grid;
  grid-template-columns: 104px 1fr 240px;
  gap: 32px;
  align-items: start;
  position: relative;
  transition: padding 0.18s ease, background 0.18s ease;
}
.task-card:first-child { border-top: 1px solid var(--ink); }
.task-card:hover {
  background: var(--paper-2);
  padding-left: 16px;
  padding-right: 16px;
}

.task-num {
  font-family: 'Fraunces', serif;
  font-variation-settings: 'opsz' 144;
  font-style: italic;
  font-weight: 300;
  font-size: 56px;
  line-height: 0.9;
  color: var(--ink-soft);
  letter-spacing: -0.02em;
}

.task-body { min-width: 0; }
.task-name {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-weight: 400;
  font-style: italic;
  font-size: 28px;
  line-height: 1.2;
  margin-bottom: 10px;
  letter-spacing: -0.015em;
  word-break: break-word;
}
.task-timestamp {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10.5px;
  color: var(--ink-muted);
  text-transform: uppercase;
  letter-spacing: 0.16em;
}

.progress-col { display: flex; flex-direction: column; gap: 10px; align-items: flex-end; }

.progress-big {
  font-family: 'Fraunces', serif;
  font-variation-settings: 'opsz' 144;
  font-style: italic;
  font-weight: 400;
  font-size: 54px;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--ink);
  white-space: nowrap;
}
.progress-big .slash { color: var(--ink-muted); margin: 0 6px; font-weight: 300; }
.progress-big .total { color: var(--ink-soft); font-weight: 300; }

.progress-breakdown {
  display: grid;
  grid-template-columns: auto auto;
  gap: 4px 14px;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.22em;
  font-weight: 600;
}
.progress-breakdown .label { color: var(--ink-soft); }
.progress-breakdown .value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0;
  color: var(--ink);
  text-align: right;
  font-weight: 500;
}
.progress-breakdown .row.done .value { color: var(--success); }
.progress-breakdown .row.stuck .value { color: var(--accent); }
.progress-breakdown .row { display: contents; }

.dot-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 3px;
  margin-top: 4px;
  justify-content: flex-end;
  max-width: 240px;
}
.dot {
  width: 10px; height: 10px;
  border: 1.5px solid var(--ink);
  background: transparent;
  display: inline-block;
}
.dot.done { background: var(--success); border-color: var(--success); }
.dot.stuck {
  background: var(--accent);
  border-color: var(--accent);
  position: relative;
}
.dot.stuck::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 44%, var(--paper) 44%, var(--paper) 56%, transparent 56%);
}

/* ==================== STUDENT: JOIN ==================== */
.student-join { max-width: 560px; }
.student-join .eyebrow { margin-bottom: 18px; }
.student-join h1 {
  font-size: clamp(56px, 10vw, 120px);
  font-weight: 300;
  font-style: italic;
  line-height: 0.95;
  margin-bottom: 14px;
  letter-spacing: -0.03em;
}
.student-join .sub {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-size: 18px;
  color: var(--ink-soft);
  margin-bottom: 48px;
  line-height: 1.4;
}

.field { margin-bottom: 32px; }
.field-label {
  display: flex;
  align-items: center;
  margin-bottom: 12px;
}
.field-label .eyebrow { white-space: nowrap; }
.field-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--ink);
  margin-left: 14px;
  opacity: 0.25;
}
.field-input {
  width: 100%;
  background: transparent;
  border: none;
  border-bottom: 2px solid var(--ink);
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-weight: 300;
  font-size: 36px;
  padding: 6px 2px;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.field-input::placeholder { color: var(--ink-muted); font-style: italic; }
.field--code .field-input {
  font-variation-settings: 'opsz' 144;
  font-size: 84px;
  letter-spacing: 0.08em;
  line-height: 1;
  padding: 6px 0;
}

.error-note {
  margin-top: 20px;
  padding: 12px 18px;
  background: var(--accent);
  color: var(--paper);
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  font-size: 13px;
  letter-spacing: 0.04em;
  font-weight: 500;
  border: 2px solid var(--ink);
  box-shadow: 5px 5px 0 var(--ink);
}
.error-note.hidden { display: none; }

/* ==================== STUDENT: JOINED ==================== */
.joined-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  padding-bottom: 20px;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 16px;
  gap: 20px;
  flex-wrap: wrap;
}
.joined-head .room-small {
  font-family: 'Fraunces', serif;
  font-variation-settings: 'opsz' 144;
  font-style: italic;
  font-weight: 300;
  font-size: 52px;
  line-height: 1;
  letter-spacing: 0.06em;
}
.joined-head .eyebrow { margin-bottom: 4px; }
.joined-head .student-name {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-size: 18px;
  color: var(--ink-soft);
  text-align: right;
}
.joined-head .student-name .label {
  display: block;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.24em;
  font-weight: 600;
  font-style: normal;
  color: var(--ink-soft);
  margin-bottom: 2px;
}

.student-task {
  padding: 26px 0;
  border-bottom: 1px solid var(--ink);
}
.student-task:first-child { border-top: 1px solid var(--ink); }
.student-task.my-done { background: rgba(44, 110, 63, 0.06); }
.student-task.my-stuck { background: rgba(184, 53, 31, 0.06); }

.student-task .task-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 4px;
}
.student-task .task-head .num {
  font-family: 'Fraunces', serif;
  font-variation-settings: 'opsz' 144;
  font-style: italic;
  font-weight: 300;
  font-size: 30px;
  color: var(--ink-soft);
  line-height: 1;
  letter-spacing: -0.01em;
}
.student-task .task-head .dash {
  flex: 1;
  height: 1px;
  background: var(--ink);
  opacity: 0.3;
}
.student-task .task-head .time {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10.5px;
  letter-spacing: 0.16em;
  color: var(--ink-muted);
  text-transform: uppercase;
}
.student-task .task-title {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-weight: 400;
  font-size: 32px;
  line-height: 1.18;
  margin: 6px 0 20px;
  letter-spacing: -0.015em;
  word-break: break-word;
}

.action-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
.action-btn {
  background: var(--paper);
  border: 2px solid var(--ink);
  padding: 20px 22px;
  cursor: pointer;
  box-shadow: 5px 5px 0 var(--ink);
  transition: transform 0.12s, box-shadow 0.12s, background 0.2s, color 0.2s;
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  color: var(--ink);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  text-align: left;
}
.action-btn .glyph {
  font-family: 'Fraunces', serif;
  font-variation-settings: 'opsz' 144;
  font-style: italic;
  font-weight: 300;
  font-size: 34px;
  line-height: 1;
}
.action-btn .action-cn {
  font-family: 'Fraunces', 'Noto Serif TC', serif;
  font-style: italic;
  font-weight: 400;
  font-size: 22px;
  letter-spacing: -0.01em;
  line-height: 1;
}
.action-btn .action-label {
  font-size: 10px;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  font-weight: 600;
  color: var(--ink-soft);
}
.action-btn:hover:not(:disabled) {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0 var(--ink);
}
.action-btn:active:not(:disabled) {
  transform: translate(5px, 5px);
  box-shadow: 0 0 0 var(--ink);
}
.action-btn:disabled { opacity: 0.5; cursor: not-allowed; }

.action-btn.done.active {
  background: var(--success);
  color: var(--paper);
}
.action-btn.done.active .action-label,
.action-btn.stuck.active .action-label { color: var(--paper); opacity: 0.8; }

.action-btn.stuck.active {
  background: var(--accent);
  color: var(--paper);
}

.my-status-line {
  margin-top: 16px;
  font-family: 'IBM Plex Sans', 'Noto Sans TC', sans-serif;
  font-size: 10.5px;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--ink-muted);
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 10px;
}
.my-status-line.done { color: var(--success); }
.my-status-line.stuck { color: var(--accent); }
.my-status-line .bullet {
  width: 6px; height: 6px; border-radius: 50%;
  background: currentColor;
}

/* ==================== RESPONSIVE ==================== */
@media (max-width: 860px) {
  .task-card { grid-template-columns: 72px 1fr; }
  .progress-col { grid-column: 1 / -1; align-items: flex-start; margin-top: 12px; }
  .dot-grid { justify-content: flex-start; }
  .progress-breakdown { grid-template-columns: auto auto auto; gap: 4px 20px; }
}

@media (max-width: 620px) {
  .role-grid { grid-template-columns: 1fr; }
  .role-grid .vertical-rule { width: 100%; height: 2px; }
  .role-card { padding: 28px 24px; }
  .role-card .role-title-cn { font-size: 44px; }
  .room-display { grid-template-columns: 1fr; gap: 32px; align-items: start; }
  .qr-frame { justify-self: start; }
  .task-form { grid-template-columns: 1fr; }
  .task-form .btn { width: 100%; justify-content: center; }
  .field--code .field-input { font-size: 64px; }
  .page-top .title { display: none; }
  .joined-head .room-small { font-size: 40px; }
  .status-bar { gap: 32px; }
  .stat-value { font-size: 36px; }
  .section-head h2 { font-size: 22px; }
  .task-num { font-size: 40px; }
  .task-name { font-size: 22px; }
  .progress-big { font-size: 44px; }
  .student-task .task-title { font-size: 24px; }
}