:root{color-scheme:light;--bg:#f6f7fb;--surface:#fff;--text:#19233b;--sub:#66738a;--line:#e8ebf2;--primary:#5147df;--primary-l:#f1efff;--orange:#ffb84d;--green:#168b64;--green-l:#e9f8f0;--red:#d84656;--red-l:#fff0f1;--navy:#20264b;--r:20px;--shadow:0 8px 24px rgba(30,43,86,.035);font-family:-apple-system,BlinkMacSystemFont,"PingFang TC","PingFang HK","Noto Sans TC","Microsoft JhengHei",sans-serif}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);-webkit-tap-highlight-color:transparent}button,input,select{font:inherit}button{cursor:pointer}button:disabled{opacity:.43;cursor:default}a{color:var(--primary);text-decoration:none}a:hover{text-decoration:underline}.app{min-height:100dvh;max-width:900px;margin:auto;background:var(--bg)}.topbar{height:76px;padding:15px max(20px,env(safe-area-inset-right)) 13px max(20px,env(safe-area-inset-left));display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:20;background:rgba(246,247,251,.93);backdrop-filter:blur(18px)}.brand{display:flex;gap:10px;align-items:center}.brand-icon{width:40px;height:40px;border-radius:13px;display:grid;place-items:center;font-weight:900;color:#fff;font-size:17px;letter-spacing:-2px;background:linear-gradient(140deg,#6a61f4,#4338bd);box-shadow:0 5px 12px #5147df30}.brand-icon span{font-size:11px;margin-left:1px;color:#ffd37d}.brand-copy strong{display:block;letter-spacing:.02em;font-size:16px}.brand-copy small{display:block;color:#9da3ba;font-size:9px;letter-spacing:2px;margin-top:2px;font-weight:700}.circle-btn{width:42px;height:42px;border:1px solid var(--line);background:white;border-radius:14px;color:var(--sub);display:grid;place-items:center}.circle-btn svg{width:19px;height:19px}.view{padding:12px 20px calc(112px + env(safe-area-inset-bottom));min-height:70dvh}.view:focus{outline:none}.eyebrow{font-size:12px;color:var(--primary);letter-spacing:2px;font-weight:800;text-transform:uppercase}.section-title{font-weight:850;letter-spacing:-.03em;font-size:24px;margin:7px 0 7px}.subtitle{color:var(--sub);font-size:13px;line-height:1.75}.hero{position:relative;overflow:hidden;border-radius:25px;background:radial-gradient(circle at 85% 20%,#505b9c 0,transparent 44%),linear-gradient(140deg,#263056,#1a2143);color:white;padding:28px 24px 24px;margin-bottom:18px;box-shadow:0 16px 30px #2b336323}.hero::after{content:"";position:absolute;width:190px;height:190px;border:1px solid #ffffff15;border-radius:50%;top:-88px;right:-60px;box-shadow:0 0 0 32px #ffffff09,0 0 0 66px #ffffff07}.hero-kicker{display:inline-flex;align-items:center;gap:7px;font-size:11px;font-weight:700;letter-spacing:.08em;color:#bfc5eb}.hero-kicker i{width:6px;height:6px;border-radius:50%;background:#ffa94d;display:inline-block}.hero h1{font-size:28px;line-height:1.3;letter-spacing:-.04em;margin:12px 0 8px;position:relative;z-index:1}.hero p{font-size:13px;color:#d5dcf7;margin:0;line-height:1.8;position:relative;z-index:1;max-width:320px}.hero .hero-actions{display:flex;gap:8px;margin-top:22px;position:relative;z-index:1}.btn{border:0;border-radius:14px;min-height:45px;padding:12px 16px;font-size:13px;font-weight:750;display:inline-flex;align-items:center;justify-content:center;gap:8px;transition:transform .15s,background .15s}.btn:active{transform:scale(.98)}.btn-primary{color:white;background:var(--primary)}.btn-on-dark{color:#24264c;background:#ffc56e}.btn-soft-dark{color:#fff;background:#ffffff24;border:1px solid #ffffff30}.btn-outline{background:#fff;border:1px solid var(--line);color:var(--text)}.btn-soft{background:var(--primary-l);color:var(--primary)}.btn-link{padding:0;border:0;background:transparent;color:var(--primary);font-weight:750;font-size:13px}.btn-block{width:100%}.btn-small{min-height:35px;padding:8px 12px;border-radius:10px;font-size:12px}.stats-strip{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-bottom:24px}.mini-stat{border-radius:17px;padding:16px 13px;background:var(--surface);box-shadow:var(--shadow);border:1px solid #eff0f6}.mini-stat .n{font-size:25px;letter-spacing:-1px;font-weight:850;font-variant-numeric:tabular-nums}.mini-stat .k{font-size:11px;color:var(--sub);margin-top:6px}.panel{background:var(--surface);border-radius:var(--r);padding:18px;margin-bottom:15px;border:1px solid #eff0f5;box-shadow:var(--shadow)}.hrow{display:flex;justify-content:space-between;align-items:center;gap:8px}.hrow h2{font-size:17px;letter-spacing:-.03em;margin:0}.hrow h3{font-size:15px;margin:0}.section-head{margin:21px 1px 12px}.mode-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:11px}.mode-card{border:1px solid #eff0f5;border-radius:19px;background:white;box-shadow:var(--shadow);padding:20px 16px;text-align:left;min-height:144px}.mode-card:active,.chapter-row:active{background:#f9f8ff}.mode-card .iconbox{width:43px;height:43px;border-radius:14px;display:grid;place-items:center;font-size:22px;margin-bottom:14px}.mode-card:nth-child(4n+1) .iconbox{background:#edeaff}.mode-card:nth-child(4n+2) .iconbox{background:#e5f7ef}.mode-card:nth-child(4n+3) .iconbox{background:#fff5e5}.mode-card:nth-child(4n+4) .iconbox{background:#ffeef0}.mode-card strong{display:block;font-size:15px;margin-bottom:5px}.mode-card small{color:var(--sub);display:block;line-height:1.6;font-size:11px}.chapter-row{display:flex;gap:13px;align-items:center;padding:15px 0;min-height:70px;border:0;border-bottom:1px solid var(--line);width:100%;background:none;text-align:left}.chapter-row:last-child{border:0}.chapter-number{background:#f1efff;color:var(--primary);border-radius:13px;width:43px;height:43px;display:grid;place-items:center;font-weight:850;flex-shrink:0}.chapter-details{flex:1;min-width:0}.chapter-details strong{font-size:13px}.chapter-details small{color:var(--sub);display:block;font-size:11px;margin-top:5px}.tiny-bar{height:5px;border-radius:5px;background:#edf0f6;overflow:hidden;margin-top:8px}.tiny-fill{height:100%;border-radius:5px;background:linear-gradient(90deg,#7770fc,#4b46db)}.row-arrow{color:#acb4c3;font-size:23px;line-height:1}.notice{background:#fff9ef;border:1px solid #ffedcb;padding:15px 16px;border-radius:16px;color:#8e6433;font-size:12px;line-height:1.8}.notice strong{color:#8b5524}.notice a{color:#a56a22;text-decoration:underline}.notice.slim{margin:14px 0}.bottom-nav{display:flex;position:fixed;bottom:0;left:0;right:0;max-width:900px;margin:auto;justify-content:space-around;background:rgba(255,255,255,.96);backdrop-filter:blur(18px);box-shadow:0 -6px 28px #17223c0b;border-top:1px solid #eceef5;padding:8px 10px calc(8px + env(safe-area-inset-bottom));z-index:24}.tab{display:flex;flex:1;flex-direction:column;align-items:center;gap:5px;background:none;border:0;color:#9aa3b5;font-size:10px;font-weight:650;padding:5px;max-width:160px}.tab svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}.tab.active{color:var(--primary)}.tab.active svg{stroke-width:2.35}.subhead{display:flex;gap:12px;align-items:center;margin-bottom:17px}.backbtn{background:white;border:1px solid var(--line);color:var(--text);height:37px;width:37px;border-radius:12px;font-size:21px}.subhead h2{font-size:19px;margin:0}.subhead p{font-size:11px;color:var(--sub);margin:4px 0 0}.practice-top{display:flex;align-items:flex-start;justify-content:space-between;gap:12px}.practice-title{font-size:20px;font-weight:800;letter-spacing:-.03em}.practice-top small{font-size:11px;color:var(--sub);display:block;margin-top:4px}.progress-wrap{background:#e7eaf3;border-radius:8px;height:7px;overflow:hidden;margin:16px 0 12px}.progress-fill{background:linear-gradient(90deg,#8773f5,var(--primary));height:100%;border-radius:9px;transition:width .2s ease}.quiz-card{background:white;border:1px solid #eef0f5;box-shadow:var(--shadow);padding:22px 20px;border-radius:24px;margin-top:12px}.quiz-meta{display:flex;gap:6px;align-items:center;flex-wrap:wrap;color:#9aa2b1;font-size:11px;margin-bottom:17px}.tag{padding:6px 10px;background:#f4f4f9;border-radius:100px;font-size:10px;color:#667189;font-weight:700}.tag-purple{color:var(--primary);background:var(--primary-l)}.tag-yellow{color:#9d7025;background:#fff4da}.tag-red{color:var(--red);background:var(--red-l)}.stem{font-size:var(--question-font,18px);line-height:1.95;white-space:pre-wrap;word-break:break-word;letter-spacing:.005em;font-weight:690;margin:0 0 21px;color:var(--text)}.option{border:1.5px solid #e9ecf3;background:white;border-radius:16px;width:100%;display:flex;gap:13px;align-items:flex-start;text-align:left;padding:14px 14px;min-height:60px;margin-bottom:11px;color:var(--text);font-size:15px;line-height:1.7;transition:border-color .16s,background .16s}.option:last-child{margin-bottom:0}.option .letter{width:29px;height:29px;border-radius:10px;background:#f3f5f9;color:#68768a;display:grid;place-items:center;font-weight:750;flex:none;line-height:1}.option .optext{flex:1;white-space:pre-wrap;word-break:break-word}.option:not([disabled]):active{background:#f5f3ff;border-color:#9e91ef}.option.picked:not(.correct):not(.wrong){background:var(--primary-l);border-color:#9d91f6}.option.picked .letter{color:white;background:var(--primary)}.option.correct{background:var(--green-l);border-color:#57bf99;color:#126c4f}.option.correct .letter{color:#fff;background:var(--green)}.option.wrong{background:var(--red-l);border-color:#f3aab3;color:#b93947}.option.wrong .letter{background:var(--red);color:white}.option[disabled]{cursor:default}.answer-box{border-radius:18px;margin-top:17px;padding:16px 17px;font-size:12px;line-height:1.85}.answer-box.correct-result{border:1px solid #c4eadd;background:#f3fcf8}.answer-box.wrong-result{border:1px solid #ffd5da;background:#fff7f8}.answer-title{font-size:15px;font-weight:800;display:flex;gap:9px;align-items:center;margin-bottom:7px}.answer-title.green{color:var(--green)}.answer-title.red{color:var(--red)}.answer-body{white-space:pre-wrap;color:#4d5c71}.answer-line{font-size:13px;margin:7px 0}.answer-line strong{color:#34435c}.extra-help{border-top:1px solid #e5e7ea;margin-top:13px;padding-top:12px;color:#4d5c71}.extra-help strong{display:block;color:#283652;font-size:12px;margin-bottom:4px}.extra-help a{display:inline-block;margin-top:9px;font-weight:800}.quiz-footer{display:flex;gap:10px;margin:14px 0;align-items:center}.quiz-footer .btn{flex:1}.quiz-actions{display:flex;align-items:center;justify-content:space-between;gap:5px;margin-top:16px}.tool-btn{border:0;padding:9px 4px;background:transparent;color:#727e91;font-size:12px;display:flex;gap:6px;align-items:center}.tool-btn.active{color:#ed8d17}.tool-btn span{font-size:18px}.quiz-caution{background:#fff7e9;color:#935b1b;font-size:12px;padding:12px 14px;border-radius:12px;line-height:1.7;margin-top:14px}.tip{margin-top:15px;color:#8992a4;font-size:11px;text-align:center;line-height:1.6}.empty{text-align:center;padding:45px 24px}.empty-art{font-size:48px;margin-bottom:16px}.empty h3{font-size:17px;margin-bottom:6px}.empty p{font-size:12px;color:var(--sub);line-height:1.9}.big-result{font-size:51px;font-weight:900;letter-spacing:-3px;margin:10px 0 4px}.result-status{color:var(--green);font-size:14px;font-weight:800}.info-list{display:grid;gap:10px;margin:14px 0}.info-item{display:flex;gap:10px;border:1px solid var(--line);border-radius:13px;padding:14px;font-size:12px;line-height:1.8;color:var(--sub)}.info-item span:first-child{flex:none;font-size:20px}.info-item strong{color:var(--text)}.form-row{margin-bottom:15px}.form-row label{display:block;font-size:12px;color:var(--sub);font-weight:700;margin-bottom:8px}.select,.search-input{width:100%;padding:13px 14px;border:1px solid #dfe3ee;background:white;border-radius:12px;color:var(--text);outline:none;font-size:14px}.select:focus,.search-input:focus{border-color:var(--primary);box-shadow:0 0 0 3px #5147df15}.filter-pills{display:flex;gap:7px;overflow:auto;padding:2px 0 14px;scrollbar-width:none}.pill{border:1px solid #e5e7ee;color:#778197;background:white;border-radius:50px;white-space:nowrap;font-size:12px;font-weight:700;padding:10px 13px}.pill.active{color:var(--primary);border-color:#aaa1f1;background:#f4f2ff}.mode-summary{padding:14px;border-radius:14px;background:#f5f4ff;color:#6561a1;font-size:12px;line-height:1.8}.chart-list{display:grid;gap:15px}.chart-item{display:grid;gap:8px}.chart-line{display:flex;justify-content:space-between;gap:10px;font-size:12px;color:var(--sub)}.chart-line strong{color:#35425a;font-weight:650}.graph-track{width:100%;background:#edf0f6;height:9px;border-radius:10px;overflow:hidden}.graph-bar{height:100%;background:#6961df;border-radius:10px}.chapter-selector{max-height:310px;overflow:auto;display:grid;gap:5px}.check-row{display:flex;align-items:center;gap:12px;border-bottom:1px solid var(--line);padding:12px 3px;font-size:13px}.check-row input{accent-color:var(--primary);height:18px;width:18px}.check-row small{color:var(--sub);margin-left:auto}.settings-card{margin-bottom:14px}.setting-line{display:flex;align-items:center;justify-content:space-between;gap:14px;padding:12px 0;border-bottom:1px solid var(--line)}.setting-line:last-child{border-bottom:0}.setting-line strong{font-size:13px}.setting-line small{font-size:11px;color:var(--sub);display:block;margin-top:5px}.font-controls{display:flex;gap:6px}.font-controls button{background:#f3f4fa;border:0;border-radius:9px;height:38px;min-width:40px}.muted{font-size:12px;color:var(--sub);line-height:1.85}.divider{height:1px;background:var(--line);margin:18px 0}.modal-layer:not([hidden]){position:fixed;inset:0;z-index:50;background:#1220399e;display:flex;align-items:flex-end;justify-content:center}.sheet{width:min(100%,650px);background:white;border-radius:26px 26px 0 0;padding:24px max(23px,env(safe-area-inset-left)) calc(25px + env(safe-area-inset-bottom));max-height:87dvh;overflow:auto;box-shadow:0 -20px 40px #16244d40}.sheet-handle{width:40px;height:5px;background:#e0e2e9;border-radius:4px;margin:-7px auto 20px}.sheet h3{font-size:21px;margin:0 0 8px}.sheet p{font-size:13px;color:var(--sub);line-height:1.85}.sheet .btn{margin-top:10px}.toast{position:fixed;bottom:calc(95px + env(safe-area-inset-bottom));left:50%;transform:translateX(-50%) translateY(12px);background:#20294b;color:white;border-radius:15px;padding:13px 20px;box-shadow:0 10px 30px #101a3e35;font-size:12px;opacity:0;transition:opacity .2s,transform .2s;pointer-events:none;z-index:99;max-width:90%;text-align:center}.toast.on{opacity:1;transform:translateX(-50%) translateY(0)}.loading{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:50dvh;color:var(--sub);font-size:13px}.spinner{display:block;width:30px;height:30px;border:3px solid #e4e2ff;border-top-color:var(--primary);border-radius:50%;animation:spin .7s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.search-results{max-height:340px;overflow:auto}.search-result{background:white;border:0;border-bottom:1px solid var(--line);width:100%;padding:14px 3px;text-align:left;font-size:12px;line-height:1.65;color:var(--text)}.search-result small{display:block;color:var(--sub);margin-bottom:3px}.source{font-size:10px;color:#9ba5b3;margin-top:4px}.offline-label{font-size:10px;color:var(--sub);padding-top:3px}.warning-title{color:#a86114;font-weight:800}.lock-screen .bg{background:radial-gradient(circle at 90% 0%,#555cc8,transparent 42%),#20284c;color:white;padding:25px;border-radius:24px}
@media(min-width:640px){.view{padding:20px 40px 120px}.topbar{padding-left:40px;padding-right:40px}.hero{padding:40px}.hero h1{font-size:34px}.mode-grid{grid-template-columns:repeat(4,minmax(0,1fr))}.quiz-card{padding:30px 33px}.stem{font-size:21px}.stats-strip{gap:15px}.mini-stat{padding:20px}.panel{padding:22px}.bottom-nav{border-radius:20px 20px 0 0}}
@media(max-width:355px){.view{padding-left:14px;padding-right:14px}.topbar{padding-left:14px;padding-right:14px}.hero{padding:23px 19px}.hero h1{font-size:24px}.quiz-card{padding:17px 14px}.option{padding:12px}.brand-copy strong{font-size:14px}.mini-stat .n{font-size:22px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{transition:none!important;animation:none!important;scroll-behavior:auto!important}}

/* ===== v2: 零基礎先修課樣式 ===== */
.lesson-topline{display:flex;align-items:center;gap:9px;margin:5px 0 14px;flex-wrap:wrap}
.lesson-back{background:transparent;border:0;color:var(--sub);padding:6px 4px;min-height:39px;font-size:13px;font-weight:750;margin-right:auto}
.lesson-status-ok{color:var(--green);background:#e7f8ef}
.lesson-title-box{border-radius:23px;padding:26px 24px;background:linear-gradient(135deg,#f0edff,#fff);border:1px solid #e7e2fc;margin-bottom:13px}
.lesson-title-box h1{font-size:27px;font-weight:850;letter-spacing:-.045em;line-height:1.35;margin:11px 0}
.lesson-title-box p{font-size:14px;color:#515b79;line-height:1.7;margin:0}
.lesson-facts{display:flex;flex-wrap:wrap;gap:9px;margin-top:19px}
.lesson-facts span{font-size:11px;background:white;border:1px solid #e7e2fc;padding:7px 10px;border-radius:10px;color:#504785;font-weight:700}
.lesson-track{margin:16px 2px 18px}
.lesson-track .hrow{color:var(--sub);font-size:12px;margin-bottom:10px}
.lesson-track .hrow strong{color:var(--primary)}
.lesson-page{padding:25px 21px 24px;border:1px solid #ececfa}
.lesson-page h2{font-size:23px;letter-spacing:-.035em;line-height:1.45;margin:7px 0 17px}
.lesson-art{font-size:43px;margin:2px 0 12px}
.lesson-description{color:var(--sub);line-height:1.9;font-size:15px;margin:0 0 20px}
.lesson-tldr{border-radius:15px;background:#f2f0ff;padding:17px;margin:18px 0}
.lesson-tldr b{font-size:14px;color:#4238bd}
.lesson-tldr p{font-size:14px;color:#3b4270;line-height:1.85;margin:6px 0 0}
.lesson-heading-small{font-size:16px;margin:23px 0 13px}
.lesson-outline{padding:0;list-style:none;counter-reset:ol;display:grid;gap:12px}
.lesson-outline li{counter-increment:ol;position:relative;min-height:44px;padding:11px 10px 11px 47px;border:1px solid var(--line);border-radius:13px;background:#fff;line-height:1.6;font-size:14px}
.lesson-outline li::before{content:counter(ol,decimal-leading-zero);position:absolute;left:12px;top:10px;width:26px;height:25px;background:var(--primary-l);color:var(--primary);border-radius:8px;display:grid;place-items:center;font-size:11px;font-weight:900}
.lesson-cta{min-height:53px;font-size:15px;margin-top:23px}
.lesson-page>.btn-block+.btn-block{margin-top:10px}
.lesson-stepnum{display:inline-flex;font-size:12px;font-weight:850;border-radius:99px;padding:8px 13px;color:var(--primary);background:var(--primary-l);margin-bottom:7px}
.lesson-paragraphs p{font-size:16px;line-height:1.9;margin:14px 0;color:#2b3550}
.lesson-paragraphs p+ p{margin-top:17px}
.lesson-example,.lesson-reminder,.lesson-trap{border-radius:16px;padding:16px 17px;margin-top:16px;border:1px solid transparent}
.lesson-example{background:#f1f7ff;border-color:#dceafa}
.lesson-reminder{background:#effaf3;border-color:#d5f0de}
.lesson-trap{background:#fff6ee;border-color:#f7e4cf}
.lesson-example h3,.lesson-reminder h3,.lesson-trap h3{font-size:13px;margin:0 0 8px;font-weight:850}
.lesson-example h3{color:#2662aa}
.lesson-reminder h3{color:#187a56}
.lesson-trap h3{color:#ac5820}
.lesson-example p,.lesson-reminder p,.lesson-trap p{font-size:14px;line-height:1.85;margin:0;color:#2c3851}
.lesson-reference{color:#7f88a0;font-size:11px;line-height:1.7;margin-top:19px;padding-bottom:8px}
.lesson-pager{display:grid;grid-template-columns:1fr 1.35fr;gap:9px;margin-top:17px}
.lesson-pager .btn{min-height:50px;padding:11px 8px}
.lesson-summary{list-style:none;padding:0;display:grid;gap:12px;margin:20px 0}
.lesson-summary li{position:relative;border-radius:12px;background:#f5f5ff;padding:13px 12px 13px 39px;line-height:1.8;font-size:14px}
.lesson-summary li:before{content:"✓";position:absolute;left:13px;top:13px;color:var(--green);font-weight:900}
.lesson-confirm{background:#fff8eb;border:1px solid #f5e4c7;border-radius:15px;padding:17px;margin:25px 0 3px}
.lesson-confirm b{color:#9d5b1b}
.lesson-confirm p{font-size:14px;line-height:1.8;margin:8px 0 0;color:#644d3a}
.lesson-footer{margin:23px 3px 0;padding-bottom:16px}
.lesson-footer h3{font-size:14px;margin:0 0 13px}
.lesson-links{display:flex;flex-wrap:wrap;gap:9px}
.lesson-links a,.lesson-links span{border-radius:10px;border:1px solid #e5e8f4;padding:10px 12px;font-size:12px;background:white}
.lesson-footer>p{font-size:12px;color:var(--sub);line-height:1.85;margin-top:15px}
.lesson-loading{text-align:center;padding:44px 20px}
.lesson-loading h2{font-size:18px}
.lesson-loading p{font-size:14px;color:var(--sub);line-height:1.7}
.learn-menu{padding:18px 18px 7px}
.learn-menu h2,.learning-settings h2{font-size:17px;margin:0 0 10px}
.learn-menu .chapter-row{width:100%}
.learn-menu .chapter-details small{color:#726a9f}
.learning-stats .chapter-row{width:100%}
@media(min-width:640px){
.lesson-title-box{padding:33px 32px}
.lesson-title-box h1{font-size:31px}
.lesson-page{padding:31px 33px}
.lesson-paragraphs p{font-size:17px}
.lesson-facts span{font-size:12px}
}
@media(max-width:365px){
.lesson-title-box{padding:20px 17px}
.lesson-title-box h1{font-size:23px}
.lesson-page{padding:20px 16px}
.lesson-page h2{font-size:21px}
.lesson-paragraphs p{font-size:15px}
.lesson-pager{grid-template-columns:1fr 1.2fr}
.lesson-pager .btn{font-size:12px}
}