:root {
  --bg: #121212; --bg2: #1e1e1e; --bg3: #2a2a2a;
  --text: #e8e8e8; --text2: #a0a0a0;
  --green: #4ade80; --green-bg: #052e16;
  --red: #f87171; --red-bg: #2d0a0a;
  --amber: #fbbf24; --amber-bg: #1c1507;
  --blue: #60a5fa; --purple: #a78bfa;
  --radius: 14px; --radius-sm: 8px;
}
* { box-sizing: border-box; margin: 0; padding: 0; -webkit-tap-highlight-color: transparent; }
body { background: var(--bg); color: var(--text); font-family: 'Segoe UI', system-ui, sans-serif; min-height: 100vh; overflow-x: hidden; }
h1,h2,h3 { font-weight: 700; }

/* Layout */
.screen { display: none; min-height: 100vh; flex-direction: column; }
.screen.active { display: flex; }
.header { padding: 16px 20px 12px; background: var(--bg2); border-bottom: 1px solid #333; display: flex; align-items: center; gap: 12px; }
.header h2 { font-size: 1.1rem; flex: 1; }
.back-btn { background: none; border: none; color: var(--text2); font-size: 1.3rem; cursor: pointer; padding: 4px 8px; border-radius: 8px; }
.back-btn:hover { background: var(--bg3); }
.content { flex: 1; padding: 20px; overflow-y: auto; }

/* Cards */
.card { background: var(--bg2); border-radius: var(--radius); padding: 16px; margin-bottom: 12px; border: 1px solid #333; }
.card:hover { border-color: #555; }

/* Category List */
.category-item { display: flex; flex-direction: column; gap: 8px; cursor: pointer; transition: transform 0.1s; }
.category-item:active { transform: scale(0.98); }
.category-header { display: flex; justify-content: space-between; align-items: center; }
.category-name { font-size: 1.05rem; font-weight: 600; }
.category-count { font-size: 0.8rem; color: var(--text2); }
.progress-bar { height: 6px; background: #333; border-radius: 3px; overflow: hidden; }
.progress-fill { height: 100%; background: var(--green); border-radius: 3px; transition: width 0.4s ease; }

/* Mode Selection */
.mode-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.mode-btn { background: var(--bg3); border: 1px solid #444; border-radius: var(--radius); padding: 16px 12px; text-align: center; cursor: pointer; transition: all 0.15s; }
.mode-btn:hover { border-color: var(--blue); background: #1a2a3a; }
.mode-btn.locked { opacity: 0.4; cursor: not-allowed; }
.mode-btn .mode-icon { font-size: 1.8rem; margin-bottom: 6px; }
.mode-btn .mode-name { font-size: 0.85rem; font-weight: 600; color: var(--text); }
.mode-btn .mode-desc { font-size: 0.72rem; color: var(--text2); margin-top: 4px; }

/* Game UI */
.game-wrap { display: flex; flex-direction: column; gap: 16px; }
.word-display { text-align: center; padding: 24px 16px; background: var(--bg2); border-radius: var(--radius); border: 1px solid #333; }
.russian-word { font-size: 2.2rem; font-weight: 700; letter-spacing: 2px; color: var(--text); line-height: 1.3; }
.hint-box { margin-top: 12px; padding: 10px 14px; background: var(--bg3); border-radius: var(--radius-sm); display: none; }
.hint-box.show { display: block; }
.hint-th { font-size: 1rem; color: var(--amber); font-weight: 600; }
.hint-en { font-size: 0.85rem; color: var(--text2); margin-top: 2px; }
.hint-pron { font-size: 0.85rem; color: var(--purple); margin-top: 4px; }

/* Helper Buttons */
.helper-row { display: flex; gap: 10px; justify-content: center; }
.helper-btn { background: var(--bg3); border: 1px solid #444; color: var(--text); border-radius: 50px; padding: 10px 20px; font-size: 0.9rem; cursor: pointer; transition: all 0.15s; display: flex; align-items: center; gap: 6px; }
.helper-btn:hover { border-color: var(--blue); }
.helper-btn.active { border-color: var(--amber); color: var(--amber); }

/* Input */
.input-area { display: flex; flex-direction: column; gap: 10px; }
.answer-input { width: 100%; background: var(--bg2); border: 2px solid #444; border-radius: var(--radius); padding: 14px 16px; font-size: 1.4rem; color: var(--text); text-align: center; letter-spacing: 3px; transition: border-color 0.2s; outline: none; }
.answer-input:focus { border-color: var(--blue); }
.answer-input.correct { border-color: var(--green); background: var(--green-bg); color: var(--green); }
.answer-input.wrong { border-color: var(--red); background: var(--red-bg); animation: shake 0.3s; }
.answer-input.shadow-mode { color: transparent; caret-color: var(--text); }
.shadow-overlay { position: relative; }
.shadow-text { position: absolute; top: 50%; left: 50%; transform: translate(-50%,-50%); font-size: 1.4rem; letter-spacing: 3px; pointer-events: none; display: flex; gap: 0; }
.shadow-char { color: rgba(255,255,255,0.25); transition: color 0.15s; }
.shadow-char.typed-correct { color: var(--green); }
.shadow-char.typed-wrong { color: var(--red); }

/* Fill in blank */
.fill-word { display: flex; gap: 6px; justify-content: center; align-items: center; flex-wrap: wrap; font-size: 1.6rem; letter-spacing: 2px; font-weight: 700; }
.fill-blank { display: inline-block; width: 44px; height: 48px; border-bottom: 3px solid var(--blue); text-align: center; color: var(--blue); }
.blank-input-mini { width: 100px; background: var(--bg2); border: 2px solid var(--blue); border-radius: 8px; padding: 8px 10px; font-size: 1.2rem; text-align: center; color: var(--text); outline: none; }

/* Word Blocks */
.blocks-area { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; min-height: 60px; padding: 12px; border: 2px dashed #444; border-radius: var(--radius); }
.blocks-pool { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; padding: 12px; background: var(--bg3); border-radius: var(--radius); }
.word-block { padding: 10px 16px; background: var(--bg2); border: 1px solid #555; border-radius: 50px; font-size: 1rem; cursor: pointer; transition: all 0.15s; font-weight: 600; user-select: none; }
.word-block:hover { border-color: var(--blue); color: var(--blue); }
.word-block.placed { background: #1a2a3a; border-color: var(--blue); color: var(--blue); }
.word-block.correct { background: var(--green-bg); border-color: var(--green); color: var(--green); }
.word-block.wrong { background: var(--red-bg); border-color: var(--red); color: var(--red); }

/* Buttons */
.btn { border: none; border-radius: var(--radius); padding: 14px 24px; font-size: 1rem; font-weight: 700; cursor: pointer; transition: all 0.15s; width: 100%; }
.btn-primary { background: var(--blue); color: #000; }
.btn-primary:hover { filter: brightness(1.1); }
.btn-success { background: var(--green); color: #000; }
.btn-danger { background: var(--red); color: #000; }
.btn-ghost { background: var(--bg3); color: var(--text); border: 1px solid #444; }

/* Result */
.result-box { text-align: center; padding: 20px; border-radius: var(--radius); }
.result-correct { background: var(--green-bg); border: 1px solid var(--green); }
.result-wrong { background: var(--red-bg); border: 1px solid var(--red); }
.result-label { font-size: 1.2rem; font-weight: 700; }
.result-answer { font-size: 1.4rem; letter-spacing: 2px; margin-top: 8px; }

/* Progress */
.progress-top { background: var(--bg3); height: 4px; position: relative; }
.progress-top-fill { height: 100%; background: var(--blue); transition: width 0.3s; }
.step-counter { font-size: 0.85rem; color: var(--text2); }

/* Home */
.home-hero { text-align: center; padding: 30px 20px 20px; }
.home-hero h1 { font-size: 2rem; margin-bottom: 6px; }
.home-hero p { color: var(--text2); font-size: 0.9rem; }
.stats-row { display: grid; grid-cols: 3; grid-template-columns: 1fr 1fr 1fr; gap: 10px; margin-bottom: 20px; }
.stat-card { background: var(--bg2); border-radius: var(--radius-sm); padding: 12px; text-align: center; border: 1px solid #333; }
.stat-val { font-size: 1.6rem; font-weight: 800; color: var(--blue); }
.stat-lbl { font-size: 0.75rem; color: var(--text2); margin-top: 2px; }

/* SRS badge */
.srs-badge { display: inline-flex; align-items: center; gap: 4px; background: var(--red-bg); border: 1px solid var(--red); color: var(--red); border-radius: 50px; padding: 4px 10px; font-size: 0.8rem; font-weight: 700; }

/* Animations */
@keyframes shake { 0%,100%{transform:translateX(0)} 25%{transform:translateX(-8px)} 75%{transform:translateX(8px)} }
@keyframes pop { 0%{transform:scale(1)} 50%{transform:scale(1.08)} 100%{transform:scale(1)} }
.pop { animation: pop 0.2s; }

/* Letter Boxes (Mode 1) */
.letter-box {
  width: 40px; height: 48px;
  border: 2px solid #555;
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem; font-weight: 700;
  transition: all 0.15s;
  cursor: text;
  user-select: none;
  flex-shrink: 0;
}

/* Scrollbar */
::-webkit-scrollbar { width: 4px; } ::-webkit-scrollbar-track { background: var(--bg); } ::-webkit-scrollbar-thumb { background: #444; border-radius: 2px; }