:root{--blue:#2563eb;--navy:#14213d;--bg:#f4f7fc;--line:#e1e8f2;--muted:#64748b;--green:#15803d;--red:#c62828}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);font-family:Inter,"Segoe UI",system-ui,Arial,sans-serif;color:#172033;-webkit-text-size-adjust:100%}
.wrap{max-width:1050px;margin:auto;padding:26px 20px 60px}
.brand{display:flex;align-items:center;gap:12px;margin-bottom:35px}
.logo{width:43px;height:43px;border-radius:13px;background:#e5efff;color:#2563eb;display:grid;place-items:center;font-size:22px}
.brand b{font-size:17px;letter-spacing:.4px}
.brand small{display:block;color:#7b8ba4;font-size:10px;letter-spacing:1.4px;margin-top:3px}
.card{background:#fff;border:1px solid var(--line);border-radius:18px;padding:24px;box-shadow:0 5px 22px #12213b08}
.center{max-width:480px;margin:7vh auto;text-align:center}
.center .logo{margin:auto;width:66px;height:66px;font-size:30px}
.title{font-size:29px;margin:17px 0 8px}
.muted{color:var(--muted);font-size:13px;line-height:1.55}
input{width:100%;border:1px solid #d6dfeb;border-radius:11px;padding:14px;font-size:16px;margin:8px 0;outline:none;background:#fff;color:#172033;opacity:1;font-family:inherit}
input::placeholder{color:#94a3b8;opacity:1}
input:focus{border-color:#78a4ff;box-shadow:0 0 0 3px #2563eb15}
input:disabled{background:#eef5ff!important;color:#17396e!important;-webkit-text-fill-color:#17396e!important;opacity:1!important;border-color:#cbdcf8}
button{border:0;border-radius:10px;padding:12px 17px;font-weight:700;cursor:pointer;font-size:13px;font-family:inherit}
button:disabled{opacity:.55;cursor:not-allowed}
.primary{background:var(--blue);color:#fff}
.soft{background:#edf2f8;color:#31435d}
.full{width:100%;margin-top:10px}
.topline{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:23px}
.eyebrow{color:var(--blue);font-size:10px;letter-spacing:1.4px;font-weight:800}
.h1{font-size:27px;margin:5px 0}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.folder{border:1px solid var(--line);border-radius:14px;background:#fff;padding:19px;cursor:pointer;transition:.15s;text-align:left;color:inherit;font-weight:400;font-size:inherit}
.folder:hover{border-color:#8cb1ff;transform:translateY(-2px)}
.folder .ico{font-size:28px;margin-bottom:12px}
.folder b{display:block;font-size:14px}
.folder small{display:block;color:var(--muted);margin-top:7px;font-size:12px}
.tag{display:inline-block;border-radius:30px;background:#edf4ff;color:#2457b8;padding:5px 9px;font-size:10px;font-weight:700;margin-top:12px}
.tag.done{background:#eaf8ef;color:#16803d}
.tag.warn{background:#fff0ed;color:#b42318}
.tag.learn{background:#fff8e7;color:#946200}
.bar{height:7px;background:#e7edf5;border-radius:8px;overflow:hidden;margin-top:12px}
.bar i{display:block;height:100%;background:var(--blue);border-radius:8px}
.crumb{color:var(--muted);font-size:12px;margin-bottom:16px}
.crumb a{color:var(--blue);text-decoration:none}
.wordlist{width:100%;border-collapse:collapse;margin-top:12px}
.wordlist td{border-bottom:1px solid #edf1f6;padding:13px 8px;font-size:13px}
.wordlist td:first-child{font-weight:700}
.stepbar{display:flex;gap:6px;margin:17px 0 22px}
.stepbar span{height:6px;flex:1;background:#e7edf5;border-radius:8px}
.stepbar span.on{background:var(--blue)}
.study{max-width:680px;margin:0 auto;text-align:center}
.studycard{height:300px;min-height:300px;position:relative;display:block;padding:0;border:0;background:transparent;perspective:1200px;cursor:pointer;margin:18px 0;width:100%}
.flip-inner{position:relative;width:100%;height:100%;border-radius:20px;transform-style:preserve-3d;transition:transform .65s cubic-bezier(.2,.75,.25,1)}
.studycard.flipped .flip-inner{transform:rotateY(180deg)}
.flip-face{position:absolute;inset:0;border-radius:20px;background:linear-gradient(140deg,#f4f8ff,#e7f0ff);border:1px solid #d8e6ff;display:flex;flex-direction:column;justify-content:center;align-items:center;padding:28px 76px;backface-visibility:hidden;-webkit-backface-visibility:hidden}
.flip-back{transform:rotateY(180deg);background:linear-gradient(140deg,#f8fbff,#eaf2ff)}
.studycard .word{font-size:36px;font-weight:800;color:#17396e;word-break:break-word}
.flash-pos{font-size:14px;font-weight:800;letter-spacing:.8px;text-transform:uppercase;color:#5275a8;background:#e1ecff;border:1px solid #cbdcff;border-radius:20px;padding:6px 13px;margin-bottom:15px}
.studycard .meaning{font-size:23px;font-weight:800;color:#17396e}
.studycard .ipa{color:#60718c;margin-top:9px;font-size:15px}
.studycard .hint{font-size:11px;color:#7890b1;margin-top:22px}
.flash-example{font-size:15px;line-height:1.6;color:#344b6d;margin-top:18px;max-width:480px}
.flash-example-label{font-size:10px;letter-spacing:1.2px;color:#7890b1;font-weight:800;margin-top:20px}
.flash-arrow{position:absolute;z-index:3;top:50%;transform:translateY(-50%);width:44px;height:44px;border-radius:50%;padding:0;background:#fff;color:#2457b8;border:1px solid #d7e4f8;box-shadow:0 3px 12px #17396e18;font-size:25px;display:grid;place-items:center}
.flash-arrow.left{left:14px}
.flash-arrow.right{right:14px}
.flash-arrow:disabled{opacity:.28;cursor:not-allowed;box-shadow:none}
.row{display:flex;justify-content:center;gap:9px;flex-wrap:wrap}
.choicegrid{display:grid;grid-template-columns:1fr 1fr;gap:11px;margin:22px 0}
.choice{background:#fff;color:#172033;border:1px solid var(--line);text-align:left;padding:16px;border-radius:11px;font-size:15px;font-weight:600}
.choice:disabled{cursor:default;opacity:1}
.choice.good{border-color:#16a34a;background:#effbf3}
.choice.bad{border-color:#dc2626;background:#fff2f2}
.feedback{min-height:26px;font-weight:700;margin:8px}
.feedback.ok{color:var(--green)}
.feedback.err{color:var(--red)}
.typing-hint{color:#c62828;font-weight:900;letter-spacing:.5px}
.hidden{display:none!important}
.finishword{display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid #edf1f6;padding:12px 2px;text-align:left;gap:10px}
.finishword b{font-size:14px}
.finishword small{display:block;color:var(--muted);margin:4px 0 2px}
.summary{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:18px 0}
.metric{background:#f6f8fc;padding:16px;border-radius:12px}
.metric b{display:block;font-size:24px}
.metric small{color:var(--muted)}
.notice{font-size:12px;color:#8a6a23;background:#fff8e7;padding:12px;border-radius:10px;margin-top:16px;text-align:left}
.errmsg{color:#c2410c;font-size:13px;margin-top:10px;min-height:18px}
.toast{position:fixed;left:50%;bottom:22px;transform:translateX(-50%);background:#14213d;color:#fff;padding:12px 18px;border-radius:10px;font-size:13px;display:none;z-index:20;max-width:90vw}
.toast.show{display:block}
.skeleton{color:var(--muted);text-align:center;padding:40px 0}
.certificate{border:2px solid #cbdcff;background:linear-gradient(140deg,#f8fbff,#eaf2ff)}
@media(max-width:680px){
  .wrap{padding:17px 13px}
  .grid{grid-template-columns:1fr 1fr}
  .h1{font-size:23px}
  .card{padding:18px}
  .choicegrid{grid-template-columns:1fr}
  .studycard .word{font-size:30px}
  .flip-face{padding:24px 58px}
  .summary{grid-template-columns:1fr 1fr}
  .brand{margin-bottom:22px}
}
@media(max-width:430px){.grid{grid-template-columns:1fr}}