/*
 * drill-engine.css
 * Shared Exercise & Speaking Engine styles.
 * Loaded by: study-space.html, scene-drills.html, tone-tutor.html
 * Classes: .ex-* (exercise UI)   .sp-* (speaking engine UI)
 */

/* ── State indicators ──────────────────────────────────────── */
.ex-loading, .ex-empty {
  text-align: center;
  color: var(--muted);
  font-size: 1rem;
  padding: 40px 0;
}

/* ── Header ─────────────────────────────────────────────────── */
.ex-header {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: clamp(12px, 2vh, 20px);
}
.ex-title {
  font-size: 22px;
  font-weight: 400;
  letter-spacing: 0.06em;
  color: var(--text);
  text-align: center;
}
.ex-progress {
  font-size: clamp(0.95rem, 1.6vh, 1.15rem);
  color: #fff;
  font-weight: 700;
}

/* ── Progress bar (shared by listening, speaking, vocabulary drills) ─ */
.ex-progress-bar-wrap {
  display: flex;
  align-items: center;
  gap: 6px;
  width: 100%;
}
.ex-progress-label, .ex-progress-total {
  font-size: clamp(0.82rem, 1.1vh, 0.95rem);
  font-weight: 700;
  color: var(--text);
  min-width: 20px;
  text-align: center;
}
.ex-progress-track {
  flex: 1;
  height: clamp(8px, 1.2vh, 12px);
  background: var(--surface2);
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--border);
}
.ex-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #4A9E6B, #5CC87E);
  border-radius: 6px;
  transition: width 0.4s ease;
}

/* ── Navigation row ─────────────────────────────────────────── */
.ex-nav-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.ex-nav-btn {
  width: 40px;
  height: 40px;
  flex-shrink: 0;
  border-radius: 50%;
  border: 2px solid var(--border);
  background: var(--surface2);
  color: var(--text);
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}
.ex-nav-btn:hover:not(:disabled) { background: var(--t4); border-color: var(--t4); }
.ex-nav-btn:disabled { opacity: 0.25; cursor: default; pointer-events: none; }

/* ── Word display ───────────────────────────────────────────── */
.ex-word-display {
  text-align: center;
  padding: clamp(16px, 3vh, 32px) 0 0;
}
.ex-char {
  font-family: 'Noto Serif SC', serif;
  font-size: clamp(2.25rem, 7.5vh, 4.5rem);
  font-weight: 700;
  line-height: 1.1;
  color: rgba(255,255,255,0.15);
  transition: color 0.3s;
}
.ex-char.revealed { color: #ffffff; }
.ex-hint {
  font-size: clamp(1.6rem, 3.3vh, 2.25rem);
  color: var(--muted);
  margin-top: 10px;
  min-height: 1.3em;
  font-weight: 500;
}
.ex-reveal { min-height: 0; margin-top: 2px; }
.ex-reveal-pinyin { font-size: clamp(1.6rem, 3.3vh, 2.25rem); font-weight: 700; }
.ex-feedback {
  font-size: clamp(0.9rem, 1.4vh, 1.1rem);
  font-weight: 700;
  margin-top: 8px;
  min-height: 1.3em;
  transition: color 0.2s;
}
.ex-feedback.correct { color: var(--t3); }
.ex-feedback.wrong   { color: var(--t1); }

/* ── Controls layout ────────────────────────────────────────── */
.ex-controls {
  display: flex;
  flex-direction: column;
  gap: clamp(8px, 1.5vh, 14px);
  width: 100%;
  max-width: min(380px, 90vw);
  margin: 0 auto;
}
.ex-action-row {
  display: flex;
  gap: clamp(6px, 1vw, 10px);
  align-items: stretch;
}

/* ── Play button ─────────────────────────────────────────────── */
.ex-play-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: clamp(7px, 1.3vh, 13px) 16px;
  border-radius: 10px;
  border: 2px solid var(--border);
  background: var(--surface2);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: clamp(0.7rem, 1vh, 0.85rem);
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.2s;
  flex-shrink: 0;
}
.ex-play-btn:hover { border-color: var(--t4); color: var(--t4); box-shadow: 0 0 12px var(--glow4); }
.ex-play-btn.playing { border-color: var(--t3); color: var(--t3); animation: ex-pulse 0.8s ease-in-out infinite; }
@keyframes ex-pulse { 0%,100% { box-shadow: 0 0 8px var(--glow3); } 50% { box-shadow: 0 0 20px var(--glow3); } }

/* ── Confirm button ─────────────────────────────────────────── */
.ex-confirm-btn {
  flex: 1;
  padding: clamp(7px, 1.3vh, 13px) 8px;
  border-radius: 10px;
  border: none;
  background: var(--t4);
  color: #fff;
  font-family: var(--font-sans);
  font-size: clamp(0.75rem, 1.1vh, 0.9rem);
  font-weight: 800;
  letter-spacing: 1px;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.2s;
}
.ex-confirm-btn:hover:not(:disabled) { transform: translateY(-1px); box-shadow: 0 6px 24px rgba(77,157,224,0.4); }
.ex-confirm-btn:disabled { opacity: 0.35; cursor: not-allowed; transform: none; }

/* ── Tone grid (2×2) ─────────────────────────────────────────── */
.ex-tone-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(5px, 0.9vh, 10px);
  width: calc(100% - 80px - clamp(12px, 2vw, 20px));
  margin: 0 auto;
}
/* 5-option fallback: lone last button centered at same width as siblings */
.ex-tone-btn:last-child:nth-child(odd) {
  grid-column: 1 / -1;
  justify-self: center;
  max-width: 50%;
}
.ex-tone-btn {
  width: 100%;
  padding: clamp(6px, 1vh, 12px) 4px;
  border-radius: 12px;
  border: 2px solid transparent;
  background: var(--surface2);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: clamp(2px, 0.3vh, 4px);
  cursor: pointer;
  transition: all 0.15s;
  overflow: hidden;
}
.ex-tone-btn:disabled { cursor: not-allowed; }

/* Always-on tone-colored outline */
.ex-tone-btn[data-tone="1"] { border-color: var(--t1); }
.ex-tone-btn[data-tone="2"] { border-color: var(--t2); }
.ex-tone-btn[data-tone="3"] { border-color: var(--t3); }
.ex-tone-btn[data-tone="4"] { border-color: var(--t4); }
.ex-tone-btn[data-tone="5"] { border-color: var(--tn); }

.ex-tone-btn .tone-pinyin { font-size: clamp(1rem, 2.4vh, 1.6rem); font-weight: 800; line-height: 1; }
.ex-tone-btn .tone-num { font-size: clamp(9px, 1.2vh, 12px); font-weight: 700; letter-spacing: 1px; text-transform: uppercase; opacity: 0.75; line-height: 1; margin-top: clamp(2px, 0.3vh, 4px); white-space: nowrap; }
.ex-tone-btn .tone-desc { font-size: clamp(9px, 1.2vh, 13px); color: var(--muted); text-align: center; margin-top: 1px; }

.ex-tone-btn[data-tone="1"]:hover:not(:disabled), .ex-tone-btn[data-tone="1"].selected { border-color: var(--t1); background: rgba(255,107,107,0.25); box-shadow: 0 0 16px var(--glow1); }
.ex-tone-btn[data-tone="2"]:hover:not(:disabled), .ex-tone-btn[data-tone="2"].selected { border-color: var(--t2); background: rgba(255,217,61,0.25); box-shadow: 0 0 16px var(--glow2); }
.ex-tone-btn[data-tone="3"]:hover:not(:disabled), .ex-tone-btn[data-tone="3"].selected { border-color: var(--t3); background: rgba(107,203,119,0.25); box-shadow: 0 0 16px var(--glow3); }
.ex-tone-btn[data-tone="4"]:hover:not(:disabled), .ex-tone-btn[data-tone="4"].selected { border-color: var(--t4); background: rgba(77,157,224,0.25); box-shadow: 0 0 16px var(--glow4); }
.ex-tone-btn[data-tone="5"]:hover:not(:disabled), .ex-tone-btn[data-tone="5"].selected { border-color: var(--tn); background: rgba(199,125,255,0.25); box-shadow: 0 0 16px var(--glown); }

.ex-tone-btn.dimmed { opacity: 0.18; border-color: transparent !important; background: var(--surface2) !important; box-shadow: none !important; }
.ex-tone-btn.correct { opacity: 1 !important; cursor: pointer !important; }
.ex-tone-btn[data-tone="1"].correct { background: rgba(255,107,107,0.25) !important; border-color: var(--t1) !important; box-shadow: 0 0 16px var(--glow1) !important; }
.ex-tone-btn[data-tone="2"].correct { background: rgba(255,217,61,0.25) !important; border-color: var(--t2) !important; box-shadow: 0 0 16px var(--glow2) !important; }
.ex-tone-btn[data-tone="3"].correct { background: rgba(107,203,119,0.25) !important; border-color: var(--t3) !important; box-shadow: 0 0 16px var(--glow3) !important; }
.ex-tone-btn[data-tone="4"].correct { background: rgba(77,157,224,0.25) !important; border-color: var(--t4) !important; box-shadow: 0 0 16px var(--glow4) !important; }
.ex-tone-btn[data-tone="5"].correct { background: rgba(199,125,255,0.25) !important; border-color: var(--tn) !important; box-shadow: 0 0 16px var(--glown) !important; }
.ex-tone-btn.wrong   { background: rgba(255,255,255,0.06) !important; border-color: #ccc !important; color: var(--muted) !important; opacity: 1 !important; cursor: pointer !important; box-shadow: none !important; }
@keyframes ex-correct-pulse {
  0%, 100% { filter: brightness(1); }
  50% { filter: brightness(1.6); }
}
.ex-tone-btn.correct-pulse { animation: ex-correct-pulse 0.8s ease-in-out 1; }
.ex-tone-btn.correct::after, .ex-tone-btn.wrong::after { content: ' 🔊'; font-size: 1.1em; opacity: 1; }

/* ── Compound word per-syllable columns ─────────────────────── */
.ex-compound-row {
  display: flex;
  gap: clamp(8px, 2vw, 16px);
  justify-content: center;
}
.ex-syl-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(4px, 0.6vh, 8px);
  flex: 1;
  max-width: 140px;
}
.ex-syl-char {
  font-family: 'Noto Serif SC', serif;
  font-size: clamp(1.6rem, 4vh, 2.8rem);
  font-weight: 700;
  color: rgba(255,255,255,0.15);
  line-height: 1.1;
  transition: color 0.3s;
}
.ex-syl-col.revealed .ex-syl-char { color: #ffffff; }
.ex-syl-btns {
  display: flex;
  flex-direction: column;
  gap: clamp(3px, 0.5vh, 6px);
  width: 100%;
}
.ex-syl-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: clamp(2px, 0.3vh, 4px);
  padding: clamp(5px, 0.8vh, 10px) 4px;
  border-radius: 10px;
  border: 2px solid transparent;
  background: var(--surface2);
  cursor: pointer;
  transition: all 0.15s;
}
.ex-syl-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.ex-syl-pinyin { font-size: clamp(0.8rem, 1.7vh, 1.1rem); font-weight: 800; line-height: 1; }
.ex-syl-tone-num { font-size: clamp(7px, 0.9vh, 10px); font-weight: 700; letter-spacing: 1px; text-transform: uppercase; opacity: 0.75; }

/* Always-on tone-colored borders */
.ex-syl-btn[data-tone="1"] { border-color: var(--t1); }
.ex-syl-btn[data-tone="2"] { border-color: var(--t2); }
.ex-syl-btn[data-tone="3"] { border-color: var(--t3); }
.ex-syl-btn[data-tone="4"] { border-color: var(--t4); }
.ex-syl-btn[data-tone="5"] { border-color: var(--tn); }

.ex-syl-btn[data-tone="1"]:hover:not(:disabled):not(.correct):not(.wrong):not(.dimmed), .ex-syl-btn[data-tone="1"].selected { border-color: var(--t1); background: rgba(255,107,107,0.25); box-shadow: 0 0 16px var(--glow1); }
.ex-syl-btn[data-tone="2"]:hover:not(:disabled):not(.correct):not(.wrong):not(.dimmed), .ex-syl-btn[data-tone="2"].selected { border-color: var(--t2); background: rgba(255,217,61,0.25); box-shadow: 0 0 16px var(--glow2); }
.ex-syl-btn[data-tone="3"]:hover:not(:disabled):not(.correct):not(.wrong):not(.dimmed), .ex-syl-btn[data-tone="3"].selected { border-color: var(--t3); background: rgba(107,203,119,0.25); box-shadow: 0 0 16px var(--glow3); }
.ex-syl-btn[data-tone="4"]:hover:not(:disabled):not(.correct):not(.wrong):not(.dimmed), .ex-syl-btn[data-tone="4"].selected { border-color: var(--t4); background: rgba(77,157,224,0.25); box-shadow: 0 0 16px var(--glow4); }
.ex-syl-btn[data-tone="5"]:hover:not(:disabled):not(.correct):not(.wrong):not(.dimmed), .ex-syl-btn[data-tone="5"].selected { border-color: var(--tn); background: rgba(199,125,255,0.25); box-shadow: 0 0 16px var(--glown); }
.ex-syl-btn.correct { opacity: 1 !important; cursor: pointer !important; }
.ex-syl-btn[data-tone="1"].correct { background: rgba(255,107,107,0.25) !important; border-color: var(--t1) !important; box-shadow: 0 0 16px var(--glow1) !important; }
.ex-syl-btn[data-tone="2"].correct { background: rgba(255,217,61,0.25) !important; border-color: var(--t2) !important; box-shadow: 0 0 16px var(--glow2) !important; }
.ex-syl-btn[data-tone="3"].correct { background: rgba(107,203,119,0.25) !important; border-color: var(--t3) !important; box-shadow: 0 0 16px var(--glow3) !important; }
.ex-syl-btn[data-tone="4"].correct { background: rgba(77,157,224,0.25) !important; border-color: var(--t4) !important; box-shadow: 0 0 16px var(--glow4) !important; }
.ex-syl-btn[data-tone="5"].correct { background: rgba(199,125,255,0.25) !important; border-color: var(--tn) !important; box-shadow: 0 0 16px var(--glown) !important; }
.ex-syl-btn.wrong   { background: rgba(255,255,255,0.06) !important; border-color: #ccc !important; color: var(--muted) !important; opacity: 1 !important; cursor: pointer !important; box-shadow: none !important; }
.ex-syl-btn.correct-pulse { animation: ex-correct-pulse 0.8s ease-in-out 1; }
.ex-syl-btn.correct::after, .ex-syl-btn.wrong::after { content: ' 🔊'; font-size: 1.1em; opacity: 1; }
.ex-syl-btn.dimmed   { opacity: 0.15; border-color: transparent !important; background: var(--surface2) !important; }

/* ── Next button ─────────────────────────────────────────────── */
.ex-next-btn {
  width: 100%;
  padding: clamp(10px, 1.5vh, 14px);
  border-radius: 10px;
  border: 2px solid var(--t4);
  background: rgba(77,157,224,0.1);
  color: var(--t4);
  font-family: var(--font-sans);
  font-size: clamp(0.8rem, 1.2vh, 0.95rem);
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.2s;
}
.ex-next-btn:hover { background: rgba(77,157,224,0.2); box-shadow: 0 0 16px rgba(77,157,224,0.15); }

/* ── Score bar ───────────────────────────────────────────────── */
.ex-score-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: clamp(10px, 1.5vh, 16px) 0;
  font-size: clamp(0.78rem, 1.1vh, 0.9rem);
  color: var(--muted);
  font-weight: 600;
}

/* ── Completion screen ───────────────────────────────────────── */
.ex-completion {
  text-align: center;
  padding: clamp(20px, 4vh, 40px) 0;
}
.ex-completion-cup { margin-bottom: clamp(12px, 2vh, 20px); }
.ex-completion-cup svg { width: clamp(60px, 12vh, 100px); height: auto; }
.ex-completion-title {
  font-size: clamp(1.2rem, 2.5vh, 1.8rem);
  font-weight: 800;
  color: var(--text);
  margin-bottom: 8px;
}
.ex-completion-score {
  font-size: clamp(2rem, 5vh, 3rem);
  font-weight: 900;
  color: var(--t4);
  margin-bottom: 4px;
}
.ex-completion-detail {
  font-size: clamp(0.8rem, 1.2vh, 0.95rem);
  color: var(--muted);
  margin-bottom: 12px;
}
.ex-completion-pass {
  font-size: clamp(0.9rem, 1.4vh, 1.1rem);
  color: var(--t3);
  font-weight: 700;
  margin-bottom: 20px;
}
.ex-completion-retry {
  font-size: clamp(0.9rem, 1.4vh, 1.1rem);
  color: var(--t2);
  font-weight: 700;
  margin-bottom: 20px;
}
.ex-completion-actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.ex-retry-btn, .ex-back-btn {
  padding: clamp(8px, 1.2vh, 12px) clamp(16px, 2.5vw, 24px);
  border-radius: 10px;
  border: none;
  font-family: var(--font-sans);
  font-size: clamp(0.78rem, 1.1vh, 0.9rem);
  font-weight: 700;
  letter-spacing: 0.5px;
  cursor: pointer;
  transition: all 0.2s;
}
.ex-retry-btn { background: var(--t2); color: #000; }
.ex-retry-btn:hover { background: #ffe566; transform: translateY(-1px); }
.ex-back-btn { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }
.ex-back-btn:hover { background: var(--border); }

/* ── Sandhi badge & popup ─────────────────────────────────────── */
.ex-sandhi-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: 6px;
  padding: 3px 10px;
  border-radius: 20px;
  background: rgba(255,217,61,0.12);
  border: 1px solid rgba(255,217,61,0.25);
  color: var(--t2);
  font-size: clamp(0.65rem, 0.9vh, 0.78rem);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}
.ex-sandhi-badge:hover { background: rgba(255,217,61,0.2); }
.ex-sandhi-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.5); z-index: 999; }
.ex-sandhi-popup {
  position: fixed;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: clamp(16px, 3vh, 28px);
  max-width: min(90vw, 340px);
  z-index: 1000;
  box-shadow: 0 8px 32px rgba(0,0,0,0.6);
}
.ex-sandhi-popup h3 { font-size: clamp(0.9rem, 1.3vh, 1.05rem); color: var(--t2); margin-bottom: 10px; }
.ex-sandhi-popup p { font-size: clamp(0.78rem, 1.1vh, 0.92rem); color: var(--text); line-height: 1.5; margin-bottom: 8px; }
.ex-sandhi-popup .ex-sandhi-rule {
  background: var(--surface2); border-radius: 8px; padding: 8px 12px;
  margin-bottom: 10px; font-size: clamp(0.85rem, 1.2vh, 1rem); font-weight: 700; text-align: center;
}
.ex-sandhi-popup button {
  display: block; width: 100%; padding: 8px; border: none; border-radius: 8px;
  background: var(--surface2); color: var(--text);
  font-family: var(--font-sans); font-size: clamp(0.78rem, 1vh, 0.9rem); font-weight: 600; cursor: pointer;
}
.ex-sandhi-popup button:hover { background: var(--border); }

/* ── Room ambient glow ───────────────────────────────────────── */
.ex-room-ambient {
  position: fixed; inset: 0;
  pointer-events: none; z-index: 0; opacity: 0;
  transition: opacity 0.9s ease, background 0.9s ease;
}
.ex-room-ambient.on { opacity: 1; }
.ex-room-ambient[data-tone="1"] { background: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(77,166,255,0.08) 0%, transparent 70%); }
.ex-room-ambient[data-tone="2"] { background: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(255,159,69,0.08) 0%, transparent 70%); }
.ex-room-ambient[data-tone="3"] { background: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(79,214,126,0.08) 0%, transparent 70%); }
.ex-room-ambient[data-tone="4"] { background: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(255,85,102,0.08) 0%, transparent 70%); }
.ex-room-ambient[data-tone="5"] { background: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(184,153,255,0.08) 0%, transparent 70%); }
.ex-room-hint {
  position: fixed; bottom: 16px; right: 20px;
  font-size: 11px; font-weight: 600; letter-spacing: 0.5px;
  padding: 4px 12px; border-radius: 20px;
  opacity: 0; transform: translateY(6px);
  transition: opacity 0.3s ease, transform 0.3s ease;
  pointer-events: none; z-index: 10;
}
.ex-room-hint.show { opacity: 0.7; transform: translateY(0); }

/* ══════════════════════════════════════════════════════════════
   Speaking Engine UI  (.sp-*)
   ══════════════════════════════════════════════════════════════ */

.sp-tab-row { display: flex; gap: 6px; margin-bottom: clamp(10px, 1.5vh, 16px); }
.sp-tab {
  flex: 1;
  padding: clamp(8px, 1.2vh, 12px) 8px;
  border-radius: 10px;
  border: 2px solid var(--border);
  background: var(--surface2);
  color: var(--muted);
  font-family: var(--font-sans);
  font-size: clamp(0.72rem, 1vh, 0.85rem);
  font-weight: 700;
  letter-spacing: 0.5px;
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}
.sp-tab.active { border-color: var(--t4); color: var(--text); background: rgba(77,157,224,0.12); box-shadow: 0 0 12px var(--glow4); }
.sp-tab .sp-tab-badge { display: inline-block; margin-left: 6px; font-size: 0.75em; opacity: 0.7; }
.sp-tab .sp-tab-badge.done { color: var(--t3); opacity: 1; }

.sp-word-display { text-align: center; padding: clamp(12px, 2.5vh, 28px) 0 clamp(6px, 1vh, 12px); }
.sp-char { font-family: 'Noto Serif SC', serif; font-size: clamp(2.5rem, 8vh, 5rem); font-weight: 700; color: #ffffff; line-height: 1.1; }
.sp-pinyin {
  font-size: clamp(1.1rem, 1.8vh, 1.4rem);
  font-weight: 700;
  margin-top: 4px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  flex-wrap: wrap;
  background: rgba(0,0,0,0.3);
  padding: 4px 14px;
  border-radius: 8px;
}
.sp-pinyin-syl { /* colored by spoken tone */ }
.sp-pinyin-syl.t1 { color: var(--t1); }
.sp-pinyin-syl.t2 { color: var(--t2); }
.sp-pinyin-syl.t3 { color: var(--t3); }
.sp-pinyin-syl.t4 { color: var(--t4); }
.sp-pinyin-syl.t5 { color: var(--tn); }
.sp-pinyin-plain { color: var(--t4); }

.sp-sandhi-badge {
  display: inline-flex; align-items: center; gap: 4px;
  margin-left: 8px; padding: 4px 12px; border-radius: 20px;
  background: rgba(255,217,61,0.12); border: 1px solid rgba(255,217,61,0.25);
  color: var(--t2); font-size: clamp(0.75rem, 1.1vh, 0.9rem); font-weight: 600; cursor: pointer; transition: all 0.2s;
}
.sp-sandhi-badge:hover { background: rgba(255,217,61,0.2); }
.sp-sandhi-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.5); z-index: 999; }
.sp-sandhi-popup {
  position: fixed; top: 50%; left: 50%; transform: translate(-50%, -50%);
  background: var(--surface); border: 1px solid var(--border); border-radius: 16px;
  padding: clamp(16px, 3vh, 28px); max-width: min(90vw, 340px); z-index: 1000;
  box-shadow: 0 8px 32px rgba(0,0,0,0.6);
}
.sp-sandhi-popup h3 { font-size: clamp(0.9rem, 1.3vh, 1.05rem); color: var(--t2); margin-bottom: 10px; }
.sp-sandhi-popup p { font-size: clamp(0.78rem, 1.1vh, 0.92rem); color: var(--text); line-height: 1.5; margin-bottom: 8px; }
.sp-sandhi-popup .sp-sandhi-rule {
  background: var(--surface2); border-radius: 8px; padding: 8px 12px;
  margin-bottom: 10px; font-size: clamp(0.85rem, 1.2vh, 1rem); font-weight: 700; text-align: center;
}
.sp-sandhi-popup button {
  display: block; width: 100%; padding: 8px; border: none; border-radius: 8px;
  background: var(--surface2); color: var(--text);
  font-family: var(--font-sans); font-size: clamp(0.78rem, 1vh, 0.9rem); font-weight: 600; cursor: pointer;
}
.sp-sandhi-popup button:hover { background: var(--border); }

.sp-meaning { font-size: clamp(1.15rem, 1.8vh, 1.4rem); color: #ffffff; margin-top: 4px; }

.sp-btn-row {
  display: flex; gap: clamp(6px, 1.2vw, 12px); align-items: center; justify-content: center;
  margin: clamp(10px, 2vh, 20px) 0;
}
.sp-nav-arrow {
  display: flex; align-items: center; justify-content: center;
  width: clamp(36px, 5vw, 44px); height: clamp(36px, 5vw, 44px);
  border-radius: 50%; border: 2px solid var(--border); background: var(--surface2);
  color: var(--text); font-size: clamp(1rem, 1.4vh, 1.3rem); cursor: pointer; transition: all 0.2s; flex-shrink: 0;
}
.sp-nav-arrow:hover { border-color: var(--accent); color: var(--accent); }
.sp-nav-arrow:disabled { opacity: 0.2; cursor: not-allowed; pointer-events: none; }

.sp-listen-btn, .sp-record-btn {
  display: flex; align-items: center; justify-content: center; gap: 8px;
  padding: clamp(10px, 1.5vh, 16px) clamp(18px, 3vw, 28px);
  border-radius: 12px; border: 2px solid var(--border); background: var(--surface2); color: var(--text);
  font-family: var(--font-sans); font-size: clamp(0.72rem, 1vh, 0.85rem);
  font-weight: 700; letter-spacing: 1.5px; text-transform: uppercase; cursor: pointer; transition: all 0.2s;
}
.sp-listen-btn:hover { border-color: var(--t4); color: var(--t4); }
.sp-listen-btn.playing { border-color: var(--t3); color: var(--t3); animation: ex-pulse 0.8s ease-in-out infinite; }

.sp-record-btn { border-color: var(--t1); color: var(--t1); }
.sp-record-btn:hover { background: rgba(255,107,107,0.08); box-shadow: 0 0 16px var(--glow1); }
.sp-record-btn:disabled { opacity: 0.35; cursor: not-allowed; }
.sp-record-btn.recording { background: rgba(255,107,107,0.15); border-color: var(--t1); animation: sp-rec-pulse 1s ease-in-out infinite; }
@keyframes sp-rec-pulse { 0%,100% { box-shadow: 0 0 8px var(--glow1); } 50% { box-shadow: 0 0 24px var(--glow1); } }

.sp-record-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--t1); display: none; }
.sp-record-btn.recording .sp-record-dot { display: inline-block; animation: sp-dot-blink 0.6s ease-in-out infinite alternate; }
@keyframes sp-dot-blink { 0% { opacity: 0.3; } 100% { opacity: 1; } }

.sp-wave-wrap { height: 36px; background: var(--surface2); border-radius: 8px; overflow: hidden; margin-bottom: clamp(8px, 1.5vh, 14px); display: none; }
.sp-wave-wrap canvas { width: 100%; height: 100%; display: block; }

.sp-tone-canvas-wrap {
  position: relative; width: 55%; max-width: 55%;
  margin-left: auto; margin-right: auto; box-sizing: border-box; flex-shrink: 0;
  background: #1c1c27; border: 1px solid var(--border); border-radius: 12px; overflow: hidden;
  margin-bottom: clamp(6px, 1vh, 10px); height: clamp(200px, 30vh, 280px);
}
.sp-tone-canvas-wrap::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,107,53,0.3), transparent); z-index: 1;
}
canvas#spToneCanvas { width: 100%; height: 100%; display: block; }
.sp-tone-legend {
  position: absolute; top: 8px; right: 10px; display: flex; gap: 10px; align-items: center;
  pointer-events: none; background: rgba(255,255,255,0.92); padding: 4px 10px; border-radius: 6px;
}
.sp-legend-item { display: flex; align-items: center; gap: 4px; font-size: 0.72rem; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; opacity: 0.9; color: #1a1a2e; }
.sp-legend-swatch { width: 7px; height: 7px; border-radius: 50%; flex-shrink: 0; }
.sp-legend-swatch.target { background: rgba(107,203,119,0.9); }
.sp-legend-swatch.spoken { background: #ff6b35; }

.sp-compare-wrap {
  flex-shrink: 0; height: clamp(200px, 30vh, 280px); width: 55%; max-width: 55%; box-sizing: border-box;
  margin-left: auto; margin-right: auto; background: #1c1c27; border: 1px solid var(--border);
  border-radius: 12px; overflow: hidden; position: relative; margin-bottom: clamp(6px, 1vh, 10px);
}
#sp-compare-canvas { width: 100%; height: 100%; display: block; }
.sp-compare-legend {
  position: absolute; top: 8px; right: 10px; display: flex; gap: 10px; align-items: center;
  pointer-events: none; background: rgba(255,255,255,0.92); padding: 4px 10px; border-radius: 6px;
}
.sp-cl-item { display: flex; align-items: center; gap: 4px; font-size: 0.72rem; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; opacity: 0.9; color: #1a1a2e; }
.sp-cl-dot { width: 7px; height: 7px; border-radius: 50%; flex-shrink: 0; }
.sp-cl-target .sp-cl-dot { background: var(--t3); }
.sp-cl-user   .sp-cl-dot { background: var(--spoken); }
.sp-cl-target { color: var(--t3); }
.sp-cl-user   { color: var(--spoken); }
.sp-pitch-badge {
  position: absolute; bottom: 6px; right: 10px; background: rgba(0,0,0,0.45); border-radius: 6px;
  padding: 3px 10px; font-size: 0.78rem; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; display: none;
}

.sp-result { text-align: center; min-height: clamp(40px, 6vh, 60px); margin-bottom: clamp(6px, 1vh, 12px); }
.sp-result-score { font-size: clamp(1.8rem, 4vh, 2.8rem); font-weight: 900; margin-bottom: 4px; }
.sp-result-score.correct { color: var(--t3); }
.sp-result-score.wrong { color: var(--t1); }
.sp-result-label { font-size: clamp(0.8rem, 1.1vh, 0.95rem); font-weight: 700; margin-bottom: 6px; }
.sp-result-label.correct { color: var(--t3); }
.sp-result-label.wrong { color: var(--t1); }

.sp-heard { font-size: clamp(0.85rem, 1.2vh, 1rem); color: var(--muted); margin-bottom: 8px; }
.sp-heard strong { color: var(--text); }

.sp-char-diff { display: flex; gap: 4px; justify-content: center; flex-wrap: wrap; margin-bottom: 8px; }
.sp-char-tile {
  display: inline-flex; align-items: center; justify-content: center;
  width: clamp(28px, 4vh, 38px); height: clamp(28px, 4vh, 38px);
  border-radius: 6px; font-family: 'Noto Serif SC', serif; font-size: clamp(1rem, 2vh, 1.4rem); font-weight: 700;
}
.sp-char-tile.correct { background: rgba(107,203,119,0.18); color: var(--t3); border: 1px solid var(--t3); }
.sp-char-tile.wrong   { background: rgba(255,107,107,0.18); color: var(--t1); border: 1px solid var(--t1); }
.sp-char-tile.extra   { background: rgba(199,125,255,0.12); color: var(--tn); border: 1px solid var(--tn); font-size: clamp(0.7rem, 1.2vh, 0.9rem); }

.sp-score-row { display: flex; align-items: center; gap: 16px; justify-content: center; margin-bottom: 10px; }
.sp-score-ring-wrap { display: flex; flex-direction: column; align-items: center; gap: 6px; flex-shrink: 0; }
.sp-score-ring { position: relative; width: 76px; height: 76px; }
.sp-score-ring svg { width: 76px; height: 76px; transform: rotate(-90deg); }
.sp-score-ring circle { fill: none; stroke-width: 7; stroke-linecap: round; }
.sp-ring-bg { stroke: var(--surface2); }
.sp-ring-fill { stroke: var(--correct); transition: stroke-dashoffset 0.6s ease, stroke 0.3s; }
.sp-score-ring-val { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; }
.sp-score-ring-num { font-size: 1.25rem; font-weight: 800; line-height: 1; }
.sp-score-ring-pct { font-size: 0.7rem; color: var(--muted); font-weight: 600; }
.sp-score-ring-msg { font-size: 0.78rem; font-weight: 700; text-align: center; color: var(--text); }

.sp-sub-scores { display: flex; flex-direction: column; gap: 10px; justify-content: center; margin: clamp(12px, 2vh, 20px) 0; }
.sp-psc { display: flex; flex-direction: column; align-items: center; gap: 3px; }
.sp-psc-label { font-size: 0.74rem; font-weight: 800; letter-spacing: 1.5px; text-transform: uppercase; color: var(--muted); }
.sp-psc-bar-track { width: 60px; height: 6px; background: var(--surface2); border-radius: 3px; overflow: hidden; }
.sp-psc-bar-fill { height: 100%; border-radius: 3px; transition: width 0.6s ease; }
.sp-psc-val { font-size: 0.72rem; font-weight: 800; }

.sp-diff-section { text-align: center; margin-bottom: 8px; }
.sp-diff-label { font-size: 0.78rem; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--muted); margin-bottom: 8px; }
.sp-char-row { display: flex; justify-content: center; flex-wrap: wrap; gap: 4px; margin-bottom: 6px; }
/* Detailed char tile (words-tab diff) — overrides simple .sp-char-tile above */
.sp-char-tile {
  display: flex; flex-direction: column; align-items: center;
  padding: 6px 9px; border-radius: 9px; border: 1px solid var(--border);
  background: var(--surface2); min-width: 44px; transition: all 0.3s;
}
.sp-char-tile.correct { border-color: var(--t3); background: rgba(107,203,119,0.12); }
.sp-char-tile.wrong   { border-color: var(--t1); background: rgba(255,77,109,0.10); }
.sp-char-tile.extra   { border-color: var(--muted); background: rgba(255,255,255,0.04); opacity: 0.6; }
.sp-ct-zh { font-family: 'Noto Serif SC', serif; font-size: 1.3rem; font-weight: 700; line-height: 1; }
.sp-ct-status { font-size: 0.74rem; font-weight: 800; margin-top: 3px; letter-spacing: 0.5px; }
.sp-char-tile.correct .sp-ct-status { color: var(--t3); }
.sp-char-tile.wrong   .sp-ct-status { color: var(--t1); }

.sp-transcript-compare { background: var(--surface2); border: 1px solid var(--border); border-radius: 10px; padding: 10px 14px; font-size: 0.82rem; }
.sp-tc-row { display: flex; align-items: baseline; gap: 8px; margin-bottom: 5px; }
.sp-tc-row:last-child { margin-bottom: 0; }
.sp-tc-label { font-size: 0.78rem; font-weight: 800; letter-spacing: 1.5px; text-transform: uppercase; color: var(--muted); min-width: 60px; flex-shrink: 0; }
.sp-tc-text { font-family: 'Noto Serif SC', serif; font-size: 0.95rem; color: var(--text); }
.sp-tc-heard { color: var(--spoken); }

.sp-status { text-align: center; font-size: clamp(0.8rem, 1.1vh, 0.95rem); color: var(--muted); min-height: 1.3em; margin-bottom: 8px; }

.sp-sub-row { display: flex; justify-content: space-between; align-items: center; padding: clamp(6px, 1vh, 10px) 0; border-bottom: 1px solid var(--border); }
.sp-sub-label { font-size: clamp(0.85rem, 1.2vh, 1rem); font-weight: 600; }
.sp-sub-val { font-size: clamp(0.85rem, 1.2vh, 1rem); font-weight: 800; }
.sp-sub-val.pass { color: var(--t3); }
.sp-sub-val.fail { color: var(--t1); }

.sp-explainer-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.55); z-index: 9999; display: flex; align-items: center; justify-content: center; }
.sp-explainer-popup {
  background: var(--card, #1e293b); border: 1px solid rgba(255,255,255,0.12);
  border-radius: 14px; padding: 28px 32px; max-width: 440px; width: 90%; text-align: center;
  box-shadow: 0 12px 40px rgba(0,0,0,0.5);
}
.sp-explainer-popup h3 { margin: 0 0 12px; font-size: 1.15rem; color: #e8a020; }
.sp-explainer-popup p { font-size: 0.88rem; line-height: 1.6; color: rgba(255,255,255,0.8); margin: 12px 0; }
.sp-explainer-popup button { margin-top: 14px; padding: 10px 32px; border-radius: 8px; border: none; background: #e8a020; color: #000; font-weight: 700; cursor: pointer; font-size: 0.95rem; }
.sp-explainer-popup button:hover { background: #f0b840; }

.sp-missed-list { margin: 16px auto; text-align: left; max-width: 340px; max-height: 200px; overflow-y: auto; }
.sp-missed-list h4 { font-size: 0.9rem; color: var(--t1); margin: 0 0 8px; text-align: center; }
.sp-missed-items { display: flex; flex-direction: column; gap: 4px; }
.sp-missed-item { display: flex; align-items: center; gap: 10px; padding: 6px 10px; background: rgba(255,255,255,0.05); border-radius: 8px; font-size: 0.85rem; }
.sp-missed-char { font-size: 1.1rem; font-weight: 700; min-width: 40px; }
.sp-missed-pinyin { color: rgba(255,255,255,0.5); min-width: 60px; }
.sp-missed-meaning { color: rgba(255,255,255,0.4); font-size: 0.8rem; }