:root{font-family:Inter,SF Pro Text,Segoe UI,Hiragino Sans,Yu Gothic UI,sans-serif;color:#16212d;background:#edf1f5;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh}button,input{font:inherit}button{cursor:pointer}.app-shell{min-height:100vh;padding:24px;background:linear-gradient(90deg,rgba(16,34,54,.06) 1px,transparent 1px),linear-gradient(rgba(16,34,54,.05) 1px,transparent 1px),#edf1f5;background-size:22px 22px}.workspace{display:grid;grid-template-columns:minmax(0,350px) minmax(0,1fr);min-height:calc(100vh - 48px);overflow:hidden;border:1px solid #c8d1dc;background:#f8fafc;box-shadow:0 18px 50px #14233624}.rail{display:flex;flex-direction:column;gap:30px;min-width:0;padding:32px;border-right:1px solid #d5dde6;color:#f6f9fc;background:#102236}.eyebrow{margin:0 0 10px;color:#8ee0c2;font-size:.78rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase}h1{margin:0;max-width:8ch;font-family:Georgia,Yu Mincho,Hiragino Mincho ProN,serif;font-size:clamp(2.25rem,4.6vw,4rem);line-height:1.02;font-weight:700;letter-spacing:0;overflow-wrap:anywhere}.search-wrap,.source-panel{display:flex;align-items:center;gap:10px}.search-wrap{min-height:46px;padding:0 12px;border:1px solid rgba(255,255,255,.18);background:#ffffff14}.search-wrap input{width:100%;min-width:0;border:0;outline:0;color:inherit;background:transparent}.search-wrap input::placeholder{color:#a9bbcb}.source-panel{margin-top:auto;color:#cbd7e2;font-size:.9rem}.dot{width:10px;height:10px;flex:0 0 auto;border-radius:50%;background:#aebccc}.dot.loading{background:#ffe17c}.dot.ready{background:#8ee0c2}.dot.error{background:#ff8f80}.error{padding:12px;border-left:4px solid #ff8f80;color:#ffece9;background:#ff8f801f;font-size:.86rem;line-height:1.55;overflow-wrap:anywhere}.practice{display:grid;grid-template-rows:auto minmax(360px,1fr) auto auto;gap:18px;min-width:0;padding:26px 28px 22px}.topbar,.toolbar,.controls,.segmented-control{display:flex;align-items:center}.topbar{justify-content:space-between;gap:14px}.toolbar{gap:10px}.segmented-control{min-height:44px;padding:4px;border:1px solid #c5d0dc;background:#e7edf3}.segmented-control>svg{margin:0 7px 0 5px;color:#607387}.segmented-control button{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:34px;padding:0 13px;border:0;color:#536273;background:transparent;font-size:.88rem;font-weight:800}.segmented-control button.is-active{color:#102236;background:#fff;box-shadow:0 1px 4px #14233629}.icon-button,.nav-button{display:inline-flex;align-items:center;justify-content:center;width:44px;height:44px;border:1px solid #bfccd9;color:#16212d;background:#fff;transition:transform .16s ease,background-color .16s ease,border-color .16s ease}.icon-button:hover,.nav-button:hover{transform:translateY(-1px);border-color:#8296aa}.icon-button:disabled{cursor:wait;opacity:.65}.segmented-control button:focus-visible,.icon-button:focus-visible,.nav-button:focus-visible,.card-stage:focus-visible,.position-control input:focus-visible{outline:3px solid #e2bd2e;outline-offset:3px}.spin{animation:spin .9s linear infinite}.card-stage{position:relative;width:min(640px,100%);min-height:420px;justify-self:center;border:0;padding:0;background:transparent;perspective:1400px}.card-stage:disabled{cursor:default}.phrase-card{position:absolute;top:0;right:0;bottom:0;left:0;display:grid;grid-template-rows:auto 1fr auto;gap:20px;padding:clamp(28px,6vw,64px);border:1px solid #c6d0db;backface-visibility:hidden;transform-style:preserve-3d;transition:transform .36s cubic-bezier(.2,.72,.2,1);box-shadow:0 24px 55px #1e2f441f}.phrase-card-front{color:#102236;background:linear-gradient(90deg,transparent 55px,rgba(216,73,74,.3) 56px,transparent 57px),repeating-linear-gradient(#fff 0,#fff 42px,#e4ebf3,#e4ebf3 44px)}.phrase-card-back{color:#07131e;background:linear-gradient(135deg,rgba(142,224,194,.22),transparent 42%),linear-gradient(#fffdf2,#fff9d8);transform:rotateY(180deg)}.card-stage.is-flipped .phrase-card-front{transform:rotateY(-180deg)}.card-stage.is-flipped .phrase-card-back{transform:rotateY(0)}.card-meta{display:flex;align-items:center;min-height:24px;color:#607387;font-size:.82rem;font-weight:900;text-transform:uppercase}.phrase-card p{align-self:center;margin:0;max-width:100%;overflow-wrap:anywhere;word-break:break-word;font-size:clamp(1.55rem,3vw,2.8rem);line-height:1.28;font-weight:800;letter-spacing:0}.target-copy{display:flex;flex-direction:column;align-self:center;align-items:center;gap:14px;min-width:0;text-align:center}.phrase-card-english p{font-family:Georgia,Times New Roman,serif;font-weight:700}.phrase-card-chinese p{font-family:PingFang SC,Microsoft YaHei,Noto Sans CJK SC,Source Han Sans SC,sans-serif;font-size:clamp(2.2rem,5.5vw,4.8rem);line-height:1.16;font-weight:700}.pinyin{color:#52697f;font-family:Segoe UI,SF Pro Text,sans-serif;font-size:clamp(1rem,2vw,1.35rem);line-height:1.4}.flip-hint{display:inline-flex;align-items:center;gap:8px;width:fit-content;color:#536273;font-size:.88rem;font-weight:800}.controls{justify-content:center;gap:16px}.nav-button{border-color:#102236}.position-control{display:grid;gap:0;width:min(640px,100%);justify-self:center}.position-control input[type=range]{--position: 0%;width:100%;height:44px;margin:0;-moz-appearance:none;appearance:none;-webkit-appearance:none;cursor:default;background:transparent}.position-control input[type=range]::-webkit-slider-runnable-track{height:8px;border:0;background:linear-gradient(to right,#29a87d var(--position),#d7e0e9 var(--position))}.position-control input[type=range]::-moz-range-track{height:8px;border:0;background:linear-gradient(to right,#29a87d var(--position),#d7e0e9 var(--position))}.position-control input[type=range]::-webkit-slider-thumb{width:0;height:0;-moz-appearance:none;appearance:none;-webkit-appearance:none}.position-control input[type=range]::-moz-range-thumb{width:0;height:0;border:0}.position-control.is-seekable input[type=range]{cursor:grab}.position-control.is-seekable input[type=range]:active{cursor:grabbing}.position-control.is-seekable input[type=range]::-webkit-slider-thumb{width:24px;height:24px;margin-top:-8px;border:4px solid #fff;border-radius:50%;background:#102236;box-shadow:0 1px 5px #10223659}.position-control.is-seekable input[type=range]::-moz-range-thumb{width:16px;height:16px;border:4px solid #fff;border-radius:50%;background:#102236;box-shadow:0 1px 5px #10223659}.position{margin:-4px 0 0;color:#536273;text-align:center;font-size:.9rem;font-weight:800}@keyframes spin{to{transform:rotate(360deg)}}@media(max-width:960px){.app-shell{padding:0}.workspace{grid-template-columns:1fr;min-height:100vh;border:0}.rail{display:grid;grid-template-columns:minmax(0,1fr) minmax(230px,.8fr);align-items:end;gap:20px 28px;padding:22px 24px;border-right:0}h1{max-width:13ch;font-size:2.55rem}.source-panel{margin-top:0}.error{grid-column:1 / -1}}@media(max-width:680px){.rail{grid-template-columns:1fr;gap:17px;padding:20px}.eyebrow{margin-bottom:6px}h1{font-size:2.1rem}.source-panel{display:none}.practice{grid-template-rows:auto minmax(300px,42vh) auto auto;gap:13px;padding:14px 16px 12px}.topbar{align-items:stretch;flex-direction:column;gap:8px}.language-control,.toolbar,.order-control{width:100%}.language-control button,.order-control button{flex:1}.order-control{min-width:0}.toolbar .icon-button{flex:0 0 44px}.card-stage{min-height:300px}.phrase-card{padding:28px}.phrase-card p{font-size:clamp(1.45rem,7vw,2.25rem)}.phrase-card-chinese p{font-size:clamp(2.5rem,13vw,4rem)}.position-control input[type=range]{height:48px}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation-duration:.01ms!important;animation-iteration-count:1!important;scroll-behavior:auto!important;transition-duration:.01ms!important}}