:root{--red:#C0392B;--red-light:#E74C3C;--red-dark:#922B21;--gold:#D4A017;--gold-light:#F0D060;--cream:#FFF8F0;--ink:#1A1A2E;--ink-light:#3D3D5C;--paper:#FFFDF7;--border:#E8DFD0;--green:#27AE60;--orange:#E67E22;--shadow:0 2px 20px rgba(26,26,46,0.08);--shadow-lg:0 8px 40px rgba(26,26,46,0.12)}
*{margin:0;padding:0;box-sizing:border-box}
body{font-family:'Be Vietnam Pro',sans-serif;background:var(--cream);color:var(--ink);min-height:100vh;overflow-x:hidden}
.header{background:linear-gradient(135deg,#922B21 0%,#C0392B 50%,#E74C3C 100%);position:sticky;top:0;z-index:100;box-shadow:0 4px 30px rgba(146,43,33,0.4)}
.header-inner{max-width:960px;margin:0 auto;padding:14px 20px;display:flex;align-items:center;justify-content:space-between}
.logo{display:flex;align-items:center;gap:12px}
.logo-icon{background:none;width:auto;height:auto;border-radius:0;display:flex;align-items:center;justify-content:center;font-family:'Noto Serif SC',serif;font-size:28px;font-weight:700;color:#FFD700;box-shadow:none}
.logo-text{color:white;font-size:20px;font-weight:700;letter-spacing:-0.5px}
.logo-sub{color:rgba(255,255,255,0.7);font-size:11px;font-weight:400}
.level-tabs{display:flex;gap:6px}


.header-badge{background:rgba(255,255,255,0.15);color:white;padding:6px 14px;border-radius:20px;font-size:12px;font-weight:500;backdrop-filter:blur(10px)}
.nav{background:white;border-bottom:1px solid var(--border);box-shadow:var(--shadow);position:sticky;top:68px;z-index:99}
.nav-inner{max-width:960px;margin:0 auto;display:flex;gap:4px;padding:10px 16px;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:none}
.nav-inner::-webkit-scrollbar{display:none}
.nav-btn{flex-shrink:0;padding:8px 16px;border:none;border-radius:20px;font-family:inherit;font-size:13px;font-weight:500;cursor:pointer;transition:all 0.2s;background:transparent;color:var(--ink-light);white-space:nowrap}
.nav-btn:hover{background:#f5f0e8}
.nav-btn.active{background:var(--red);color:white;box-shadow:0 2px 10px rgba(192,57,43,0.3)}
.main{max-width:960px;margin:0 auto;padding:24px 16px 100px}
.home-hero{text-align:center;padding:40px 20px 32px}
.home-hero h1{font-family:'Noto Serif SC',serif;font-size:40px;font-weight:700;color:var(--red);margin-bottom:6px}
.home-hero p{font-size:15px;color:var(--ink-light);max-width:520px;margin:0 auto 24px;line-height:1.6}
.stats-row{display:flex;justify-content:center;gap:30px;margin-bottom:32px}
.stat{text-align:center}
.stat-num{font-size:30px;font-weight:700;color:var(--red);font-family:'Noto Serif SC',serif}
.stat-label{font-size:12px;color:var(--ink-light);margin-top:2px}
.section-title{font-family:'Noto Serif SC',serif;font-size:22px;font-weight:700;color:var(--ink);margin:28px 0 14px;padding-left:14px;border-left:4px solid var(--red);display:flex;align-items:center;gap:10px}
.section-title .badge{font-size:12px;padding:3px 12px;border-radius:12px;font-family:'Be Vietnam Pro',sans-serif;font-weight:600;color:white}
.badge-hsk1{background:#D96B64}
.badge-hsk2{background:#E67E22}
.lesson-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(270px,1fr));gap:12px;margin-bottom:12px}
.lesson-card{background:white;border:1px solid var(--border);border-radius:14px;padding:18px 20px;cursor:pointer;transition:all 0.25s;position:relative;overflow:hidden}
.lesson-card::before{content:'';position:absolute;top:0;left:0;width:4px;height:100%;background:var(--red);opacity:0;transition:opacity 0.25s}
.lesson-card.hsk2::before{background:var(--orange)}
.lesson-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg);border-color:var(--red)}
.lesson-card.hsk2:hover{border-color:var(--orange)}
.lesson-card:hover::before{opacity:1}
.lesson-num{font-family:'Noto Serif SC',serif;font-size:12px;font-weight:700;color:var(--red);margin-bottom:4px}
.lesson-card.hsk2 .lesson-num{color:var(--orange)}
.lesson-title-cn{font-family:'Noto Sans SC',sans-serif;font-size:20px;font-weight:700;color:var(--ink);margin-bottom:2px}
.lesson-title-vi{font-size:13px;color:var(--ink-light);margin-bottom:8px}
.lesson-meta{display:flex;gap:8px}
.lesson-tag{font-size:11px;padding:3px 10px;border-radius:10px;background:#FFF0E6;color:var(--red);font-weight:500}
.lesson-card.hsk2 .lesson-tag{background:#FFF3E6;color:var(--orange)}
.back-btn{display:inline-flex;align-items:center;gap:6px;font-family:inherit;font-size:14px;color:var(--ink-light);background:none;border:none;cursor:pointer;margin-bottom:14px;padding:6px 0}
.back-btn:hover{color:var(--red)}
.lesson-view-title{font-family:'Noto Serif SC',serif;font-size:30px;font-weight:700;color:var(--ink)}
.lesson-view-sub{font-size:14px;color:var(--ink-light);margin-top:4px;margin-bottom:20px}
.mode-tabs{display:flex;gap:8px;margin-bottom:20px;flex-wrap:wrap}
.mode-tab{padding:10px 22px;border:2px solid var(--border);border-radius:12px;font-family:inherit;font-size:14px;font-weight:600;cursor:pointer;transition:all 0.2s;background:white;color:var(--ink-light)}
.mode-tab:hover{border-color:var(--red);color:var(--red)}
.mode-tab.active{border-color:var(--red);background:var(--red);color:white}
.word-list{display:flex;flex-direction:column;gap:7px}
.word-item{background:white;border:1px solid var(--border);border-radius:12px;padding:14px 18px;display:grid;grid-template-columns:auto auto 1fr auto;gap:14px;align-items:center;transition:all 0.2s}
.word-item:hover{border-color:var(--gold);box-shadow:var(--shadow)}
.word-hanzi{font-family:'Noto Sans SC',sans-serif;font-size:26px;font-weight:700;color:var(--ink);min-width:60px}
.word-info{min-width:0}
.word-pinyin{font-size:14px;color:var(--red);font-weight:500;margin-bottom:1px}
.word-meaning{font-size:13px;color:var(--ink-light);line-height:1.4}
.word-pos{font-size:11px;padding:3px 10px;border-radius:8px;background:#f0ebe3;color:var(--ink-light);font-weight:500;white-space:nowrap}
.flashcard-container{display:flex;flex-direction:column;align-items:center;padding:16px 0}
.flashcard-progress{font-size:14px;color:var(--ink-light);margin-bottom:18px}
.flashcard{width:100%;max-width:400px;min-height:300px;perspective:1000px;cursor:pointer;margin-bottom:22px}
.flashcard-inner{position:relative;width:100%;height:100%;min-height:300px;transition:transform 0.6s cubic-bezier(0.4,0,0.2,1);transform-style:preserve-3d}
.flashcard-inner.flipped{transform:rotateY(180deg)}
.flashcard-front,.flashcard-back{position:absolute;width:100%;height:100%;min-height:300px;backface-visibility:hidden;border-radius:20px;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:36px 28px;text-align:center}
.flashcard-front{background:linear-gradient(145deg,white 0%,#FFF8F0 100%);border:2px solid var(--border);box-shadow:var(--shadow-lg)}
.flashcard-back{background:linear-gradient(145deg,var(--red) 0%,var(--red-dark) 100%);transform:rotateY(180deg);color:white;box-shadow:0 8px 40px rgba(192,57,43,0.3)}
.fc-hanzi{font-family:'Noto Serif SC',serif;font-size:68px;font-weight:700;color:var(--ink);margin-bottom:10px;line-height:1.1}
.fc-hint{font-size:13px;color:var(--ink-light);opacity:0.5;margin-top:14px}
.fc-pinyin{font-size:26px;font-weight:600;margin-bottom:14px;color:rgba(255,255,255,0.95)}
.fc-meaning{font-size:18px;line-height:1.5;color:rgba(255,255,255,0.85)}
.fc-controls{display:flex;gap:10px}
.fc-btn{padding:11px 26px;border:none;border-radius:12px;font-family:inherit;font-size:14px;font-weight:600;cursor:pointer;transition:all 0.2s}
.fc-btn.prev{background:white;color:var(--ink);border:2px solid var(--border)}
.fc-btn.prev:hover{border-color:var(--red);color:var(--red)}
.fc-btn.next{background:var(--red);color:white}
.fc-btn.next:hover{background:var(--red-dark)}
.fc-btn:disabled{opacity:0.3;cursor:not-allowed}
.shuffle-btn{padding:8px 14px;background:white;border:2px solid var(--border);border-radius:10px;font-family:inherit;font-size:13px;font-weight:500;cursor:pointer;color:var(--ink-light);transition:all 0.2s}
.shuffle-btn:hover{border-color:var(--gold);color:var(--gold)}
.toolbar{display:flex;gap:8px;align-items:center;margin-bottom:14px;flex-wrap:wrap}
.word-count{font-size:13px;color:var(--ink-light);margin-left:auto}
.quiz-container{max-width:560px;margin:0 auto;padding:16px 0}
.quiz-progress-bar{width:100%;height:6px;background:var(--border);border-radius:3px;margin-bottom:22px;overflow:hidden}
.quiz-progress-fill{height:100%;background:linear-gradient(90deg,var(--red),var(--gold));border-radius:3px;transition:width 0.4s ease}
.quiz-question{text-align:center;margin-bottom:28px}
.quiz-q-label{font-size:13px;color:var(--ink-light);margin-bottom:10px}
.quiz-q-hanzi{font-family:'Noto Serif SC',serif;font-size:52px;font-weight:700;color:var(--ink);margin-bottom:4px}
.quiz-q-pinyin{font-size:17px;color:var(--red);font-weight:500}
.quiz-options{display:flex;flex-direction:column;gap:9px}
.quiz-option{width:100%;padding:14px 18px;background:white;border:2px solid var(--border);border-radius:14px;font-family:inherit;font-size:15px;color:var(--ink);cursor:pointer;transition:all 0.2s;text-align:left}
.quiz-option:hover:not(.correct):not(.wrong){border-color:var(--red);background:#FFF5F3}
.quiz-option.correct{border-color:var(--green);background:#EAFAF1;color:var(--green);font-weight:600}
.quiz-option.wrong{border-color:#E8918A;background:#FFF0EE;color:#E8918A}
.quiz-result{text-align:center;padding:36px 20px}
.quiz-score{font-family:'Noto Serif SC',serif;font-size:60px;font-weight:700;color:var(--red)}
.quiz-score-label{font-size:15px;color:var(--ink-light);margin-bottom:22px}
.quiz-restart{padding:13px 34px;background:var(--red);color:white;border:none;border-radius:12px;font-family:inherit;font-size:15px;font-weight:600;cursor:pointer}
.quiz-restart:hover{background:var(--red-dark)}
.review-card{border:2px dashed var(--gold) !important;background:linear-gradient(135deg,#FFFDF0,#FFF8E8) !important}
.review-card:hover{border-color:var(--gold) !important;box-shadow:0 8px 30px rgba(212,160,23,0.2) !important}
.review-card::before{background:var(--gold) !important}
.audio-btn{background:none;border:none;cursor:pointer;font-size:18px;padding:4px 8px;border-radius:8px;transition:all 0.15s;opacity:0.5;flex-shrink:0}
.audio-btn:hover{opacity:1;background:rgba(192,57,43,0.08);transform:scale(1.15)}
.audio-btn:active{transform:scale(0.95)}
.lesson-card.hsk79{border-left:3px solid #8E44AD}
.lesson-card.hsk79:hover{border-color:#8E44AD}
.lesson-card.hsk79 .lesson-tag{background:#F4ECF7;color:#8E44AD}
.word-item{cursor:pointer}
.word-strokes{grid-column:1/-1;padding:12px 0 4px;border-top:1px dashed var(--border);margin-top:10px;display:flex;flex-wrap:wrap;gap:10px;align-items:center}
.stroke-char{display:flex;flex-direction:column;align-items:center;gap:4px}
.stroke-char svg{border:1px solid var(--border);border-radius:10px;background:white}
.stroke-char span{font-size:11px;color:var(--ink-light)}
.stroke-play{padding:6px 14px;border:1px solid var(--border);border-radius:8px;font-family:inherit;font-size:12px;cursor:pointer;background:white;color:var(--red);font-weight:500;transition:all 0.2s;white-space:nowrap}
.stroke-play:hover{background:var(--red);color:white}
.lesson-card.hsk3{border-left:3px solid #27AE60}
.lesson-card.hsk3:hover{border-color:#27AE60}
.lesson-card.hsk3 .lesson-num{color:#27AE60}
@keyframes fadeIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}
.fade-in{animation:fadeIn 0.3s ease forwards}

.typing-wrap{max-width:620px;margin:0 auto;background:#fff;border:1px solid var(--border);border-radius:20px;padding:28px;box-shadow:var(--shadow)}
.typing-vi{text-align:center;font-size:28px;font-weight:700;color:var(--red);margin-bottom:10px}
.typing-answer{font-family:'Noto Serif SC',serif;font-size:72px;text-align:center;margin:12px 0;color:var(--ink)}
.typing-input{width:100%;padding:18px;border:2px solid var(--border);border-radius:14px;font-size:28px;text-align:center}
.typing-status{text-align:center;margin-top:12px;font-weight:700}
@media(max-width:600px){.lesson-grid{grid-template-columns:1fr}.fc-hanzi{font-size:52px}.quiz-q-hanzi{font-size:40px}.stats-row{gap:14px}.stat-num{font-size:22px}.home-hero h1{font-size:30px}.word-item{grid-template-columns:auto auto 1fr}.word-pos{display:none}.level-tabs{gap:4px}.level-tab{padding:6px 12px;font-size:12px}}