:root{--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light;--bg:#f6f1e8;--panel:#ffffffe0;--panel-border:#2f1f0f1f;--text:#1f1a14;--muted:#6a5e52;--primary:#1f4e79;--primary-strong:#173a5a;--success:#0d6b3d;--error:#8f2a1a;--shadow:0 24px 68px #33210b24;--radius:24px}*{box-sizing:border-box}html,body{min-height:100%}body{color:var(--text);background:radial-gradient(circle at top left, #d6a9543d, transparent 34%), radial-gradient(circle at right top, #1f4e7929, transparent 28%), linear-gradient(180deg, #fbf7f1 0%, var(--bg) 100%);margin:0;font-family:Trebuchet MS,Gill Sans,Segoe UI,sans-serif}body:before{content:"";pointer-events:none;background-image:linear-gradient(#1f1a1408 1px,#0000 1px),linear-gradient(90deg,#1f1a1408 1px,#0000 1px);background-size:42px 42px;position:fixed;inset:0;-webkit-mask-image:linear-gradient(#00000059,#0000 70%);mask-image:linear-gradient(#00000059,#0000 70%)}#app{width:100%}.shell{gap:18px;width:min(900px,100% - 32px);margin:0 auto;padding:40px 0 56px;display:grid}.hero{text-align:center;padding:8px 4px 6px}.eyebrow,.panel-kicker{text-transform:uppercase;letter-spacing:.18em;color:var(--muted);margin:0 0 6px;font-size:.75rem;font-weight:700}h1,h2,p{margin:0}h1{letter-spacing:-.04em;font-family:Georgia,Times New Roman,serif;font-size:clamp(2.8rem,7vw,4.8rem);line-height:.95}.lead{max-width:60ch;color:var(--muted);margin-top:14px;margin-left:auto;margin-right:auto;font-size:1.05rem;line-height:1.6}.panel{background:var(--panel);border:1px solid var(--panel-border);border-radius:var(--radius);box-shadow:var(--shadow);-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);padding:22px}.panel-header{justify-content:space-between;align-items:flex-start;gap:16px;margin-bottom:18px;display:flex}h2{font-size:1.3rem;line-height:1.2}.challenge-panel{background:linear-gradient(135deg, #fffffff0, #fff7e4d1), var(--panel)}.instructions{color:var(--text);gap:10px;margin:0;padding-left:1.2rem;line-height:1.55;display:grid}.digit-grid{grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;display:grid}.digit-box{background:linear-gradient(#fffdf9 0%,#f1e6d3 100%);border:1px solid #1f1a141f;border-radius:20px;place-items:center;min-height:92px;font-family:Georgia,Times New Roman,serif;font-size:clamp(2rem,5vw,3rem);font-weight:700;display:grid;box-shadow:inset 0 1px #ffffffd9}button.digit-box{cursor:pointer;appearance:none;width:100%;color:var(--text);border:1px solid #1f1a141f;place-items:center;padding:0;display:grid}button.digit-box:disabled,button.digit-box:disabled:hover{cursor:not-allowed;transform:none}.digit-box--used{background:linear-gradient(#393a3f 0%,#e6e9ee 100%);border-color:#bfc5ce;box-shadow:inset 0 1px #ffffffa6,inset 0 0 0 999px #5050500a}.formula-form{gap:12px;display:grid}.formula-label{font-weight:700}.mode-row{gap:8px;display:grid}.mode-switch{background:#1f4e7914;border:1px solid #1f1a141f;border-radius:18px;gap:4px;width:fit-content;padding:4px;display:inline-flex}.mode-switch-button{min-height:42px;color:var(--primary-strong);box-shadow:none;background:0 0;border-radius:14px;padding:0 16px}.mode-switch-button:hover{transform:none}.mode-switch-button--active{color:#fff;background:linear-gradient(180deg, var(--primary) 0%, var(--primary-strong) 100%);box-shadow:0 10px 18px #1f4e792e}.mode-switch-button--active:hover{transform:none}.keypad-group{gap:8px;display:grid}.keypad{grid-template-columns:repeat(auto-fit,minmax(72px,1fr));gap:10px;display:grid}.keypad-button{min-height:42px;padding:0 14px}.keypad-button:disabled,.keypad-button:disabled:hover{opacity:.58;color:#173a5ab3;box-shadow:none;background:#1f4e790a;border:1px solid #1f4e7914}.hint{color:var(--muted);margin-top:-2px;font-size:.95rem;line-height:1.45}#formula-input{width:100%;min-height:54px;font:inherit;color:var(--text);background:#fffffff2;border:1px solid #1f1a1433;border-radius:16px;outline:none;padding:0 16px;font-size:1.05rem;transition:border-color .12s,box-shadow .12s}#formula-input:focus{border-color:#1f4e7973;box-shadow:0 0 0 4px #1f4e791f}.button-row{flex-wrap:wrap;gap:10px;display:flex}button{font:inherit;cursor:pointer;border:0;border-radius:999px;justify-content:center;align-items:center;font-weight:700;transition:transform .12s,box-shadow .12s,background-color .12s;display:inline-flex}button:hover{transform:translateY(-1px)}button:disabled,button:disabled:hover{cursor:not-allowed;transform:none}button:focus-visible{outline-offset:2px;outline:3px solid #1f4e7947}.primary-button,.ghost-button{min-height:46px;padding:0 18px}.primary-button{color:#fff;background:linear-gradient(180deg, var(--primary) 0%, var(--primary-strong) 100%);box-shadow:0 12px 24px #1f4e7933}.ghost-button{color:var(--primary-strong);background:#1f4e7914}.ghost-button:disabled{color:#173a5a99;box-shadow:none;opacity:.95;background:#1f4e790d}.danger-ghost{color:#8f2a1a;background:#8f2a1a14}.danger-ghost:disabled{color:#8f2a1a9e;background:#8f2a1a0d}.solution{color:var(--primary-strong);background:#1f4e7914;border:1px solid #1f4e791f;border-radius:14px;margin-bottom:12px;padding:12px 16px;font-weight:600;line-height:1.5}.history-list{gap:12px;display:grid}.history-empty{color:var(--muted);margin:0;line-height:1.5}.history-item{background:#ffffffbd;border:1px solid #1f1a141a;border-radius:18px;grid-template-columns:minmax(0,1fr) auto;gap:14px;padding:14px 16px;display:grid}.history-details{gap:8px;min-width:0;display:grid}.history-topline{flex-wrap:wrap;align-items:center;gap:10px;display:flex}.history-digits{letter-spacing:.04em;font-weight:700}.history-status-wrap{flex-wrap:wrap;align-items:center;gap:8px;display:inline-flex}.history-status{border-radius:999px;align-items:center;min-height:26px;padding:0 10px;font-size:.84rem;font-weight:700;display:inline-flex}.history-repeat-count{min-height:22px;color:var(--muted);background:#1f1a1414;border-radius:999px;align-items:center;padding:0 8px;font-size:.78rem;font-weight:700;display:inline-flex}.history-mode-badge{min-height:22px;color:var(--primary-strong);background:#1f4e7914;border-radius:999px;align-items:center;padding:0 8px;font-size:.78rem;font-weight:700;display:inline-flex}.history-status--success{color:var(--success);background:#0d6b3d14}.history-status--error{color:var(--error);background:#8f2a1a14}.history-formula,.history-error,.history-time{word-break:break-word;line-height:1.45}.history-formula{font-weight:600}.history-error,.history-time{color:var(--muted);font-size:.92rem}.history-actions{align-items:flex-start;display:flex}.history-action-button{white-space:nowrap;min-height:40px;padding:0 16px}.history-modal{width:min(760px,100% - 24px);color:var(--text);background:0 0;border:0;border-radius:24px;padding:0}.history-modal::backdrop{-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px);background:#120e0a8a}.history-modal__content{background:linear-gradient(#fffffffa,#f9f3eafa);border:1px solid #2f1f0f1f;border-radius:24px;max-height:calc(100vh - 48px);padding:22px;overflow:auto;box-shadow:0 28px 88px #140e083d}.history-modal__header{margin-bottom:14px}.history-modal__details{gap:10px;margin-bottom:16px;display:grid}.history-modal__line,.history-modal__status{word-break:break-word;line-height:1.5}.history-modal__mode{color:var(--muted);font-size:.92rem;line-height:1.45}.history-modal__status{font-weight:700}.history-modal__steps{gap:10px;display:grid}.history-modal__steps-title{margin:0;font-size:1rem;line-height:1.3}.result{background:#ffffffb8;border:1px solid #1f1a1414;border-radius:16px;align-items:center;min-height:3rem;padding:14px 16px;font-weight:600;line-height:1.5;display:grid}.result--idle{color:var(--muted)}.result--success{color:var(--success);background:#edfbf3eb;border-color:#0d6b3d2e}.result--error{color:var(--error);background:#fff2eff2;border-color:#8f2a1a2e}.steps{gap:10px;margin:0;padding-left:1.25rem;display:grid}.steps li{line-height:1.55}.steps-empty{color:var(--muted);padding-left:0;list-style:none}@media (width<=640px){.shell{gap:14px;width:min(100% - 20px,900px);padding-top:18px;padding-bottom:28px}.panel{padding:18px}.panel-header{flex-direction:column}.hero{text-align:left}.lead{margin-left:0;margin-right:0}.digit-grid{gap:10px}.digit-box{min-height:76px}.button-row,.mode-row,.mode-switch{width:100%}.keypad{grid-template-columns:repeat(4,minmax(0,1fr))}.mode-switch-button{flex:1 1 0}.primary-button,.ghost-button,.history-action-button{justify-content:center;width:100%}.history-item{grid-template-columns:1fr}.history-actions{width:100%}.history-modal{width:min(100% - 12px,760px)}.history-modal__content{border-radius:20px;max-height:calc(100vh - 24px);padding:18px}}