:root{--bg-primary:#171717;--bg-secondary:#191919;--surface:#202020;--surface-2:#242424;--display:#343434;--text-primary:#f5f5f5;--text-secondary:#b9b9b9;--button-light:#f7f7f7;--button-light-text:#111;--button-dark:#202020;--border:rgba(255,255,255,.12);--border-strong:rgba(255,255,255,.2);--shadow:0 24px 70px rgba(0,0,0,.42);--radius:28px;--radius-sm:22px}
html[data-theme=light]{--bg-primary:#e9e9e9;--bg-secondary:#f4f4f4;--surface:#e7e7e7;--surface-2:#dedede;--display:#d4d4d4;--text-primary:#111;--text-secondary:#555;--button-light:#fff;--button-light-text:#111;--button-dark:#ececec;--border:rgba(0,0,0,.1);--border-strong:rgba(0,0,0,.16);--shadow:0 24px 70px rgba(0,0,0,.12)}
@media(prefers-color-scheme:light){html[data-theme=system]{--bg-primary:#e9e9e9;--bg-secondary:#f4f4f4;--surface:#e7e7e7;--surface-2:#dedede;--display:#d4d4d4;--text-primary:#111;--text-secondary:#555;--button-light:#fff;--button-light-text:#111;--button-dark:#ececec;--border:rgba(0,0,0,.1);--border-strong:rgba(0,0,0,.16);--shadow:0 24px 70px rgba(0,0,0,.12)}}
*{margin:0;padding:0;box-sizing:border-box}html,body{width:100%;min-height:100%;overflow-x:hidden}body{font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:var(--bg-primary);color:var(--text-primary);min-height:100vh;transition:background .25s ease,color .25s ease}
.container-fluid{min-height:100vh;padding:18px;display:flex;align-items:center;justify-content:center;transition:transform .28s cubic-bezier(.22,.8,.25,1)}.calculator-container{width:min(100%,390px);margin:0 auto}.calculator{position:relative;overflow:hidden;width:100%;padding:16px;background:var(--bg-secondary);border:1px solid var(--border-strong);border-radius:var(--radius);box-shadow:var(--shadow);backdrop-filter:blur(18px)}
.display-container{position:relative;min-height:126px;margin-bottom:16px;padding:18px;display:flex;flex-direction:column;justify-content:center;background:var(--display);border:1px solid var(--border);border-radius:var(--radius-sm);box-shadow:inset 0 1px 0 rgba(255,255,255,.08),inset 0 -18px 35px rgba(0,0,0,.08)}.expression-preview{min-height:15px;color:var(--text-secondary);font-size:12px;font-weight:500;text-align:right;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;opacity:0;transform:translateY(3px);transition:opacity .15s ease,transform .15s ease}.expression-preview.active{opacity:.9;transform:translateY(0)}.display-secondary{min-height:18px;margin-bottom:5px;color:var(--text-secondary);font-size:15px;text-align:right}.display-primary{color:var(--text-primary);font-size:2.65rem;font-weight:400;letter-spacing:-.045em;text-align:right;word-break:break-all}
.button-grid{position:relative;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px}.btn{position:relative;overflow:hidden;isolation:isolate;height:58px;display:flex;align-items:center;justify-content:center;border:1px solid rgba(255,255,255,.08);border-radius:18px;background:var(--button-dark);color:var(--text-primary);font:500 1.15rem Inter,sans-serif;cursor:pointer;box-shadow:0 3px 8px rgba(0,0,0,.22);transition:background .18s ease,border-color .18s ease,box-shadow .18s ease,filter .18s ease}.btn::after{content:"";position:absolute;inset:0;background:rgba(255,255,255,.06);opacity:0;transition:opacity .18s ease;pointer-events:none;z-index:1}.btn>*{position:relative;z-index:2}.btn:hover{border-color:var(--border-strong);box-shadow:0 6px 14px rgba(0,0,0,.25)}.btn:active{transform:none}.btn:focus-visible{outline:2px solid var(--text-primary);outline-offset:2px}.btn-function,.btn-operator{background:var(--button-light);color:var(--button-light-text);border-color:rgba(0,0,0,.06);font-weight:500}.btn-function:hover,.btn-operator:hover{color:var(--button-light-text);border-color:rgba(0,0,0,.12);filter:brightness(.97)}.btn-number{background:var(--button-dark);color:var(--text-primary)}.btn-zero{grid-column:span 2}.btn-equals{background:#000;color:#fff;border-color:#000;font-weight:500}.btn-equals:hover{background:#090909;filter:none}.btn-backspace i{font-size:.9em}
.history-panel{display:none;margin-bottom:12px;overflow:hidden;border:1px solid var(--border);border-radius:16px;background:var(--surface)}.history-panel.is-open{display:block}.history-header{display:flex;align-items:center;justify-content:space-between;padding:10px 12px;color:var(--text-primary);font-size:12px;border-bottom:1px solid var(--border)}.history-count{min-width:20px;padding:2px 6px;border-radius:8px;background:var(--surface-2);text-align:center}.history-list{max-height:180px;overflow:auto}.history-empty{padding:18px 12px;color:var(--text-secondary);font-size:12px;text-align:center}.history-item{width:100%;display:flex;justify-content:space-between;gap:10px;padding:10px 12px;border:0;border-bottom:1px solid var(--border);background:var(--surface);color:var(--text-primary);font:400 12px/1.2 Inter,sans-serif;text-align:left;cursor:pointer}.history-item:hover{background:var(--surface-2)}.history-result{font-weight:600}
.sidebar-open{position:fixed;top:18px;right:18px;left:auto;z-index:1001;width:38px;height:38px;border:1px solid var(--border-strong);border-radius:11px;background:var(--surface);color:var(--text-primary);cursor:pointer;box-shadow:0 7px 18px rgba(0,0,0,.28)}.sidebar-open:hover{border-color:var(--text-primary)}.sidebar-backdrop{position:fixed;inset:0;z-index:999;background:rgba(0,0,0,.58);backdrop-filter:blur(3px);opacity:0;pointer-events:none;transition:opacity .22s ease}.sidebar-backdrop.is-open{opacity:1;pointer-events:auto}.feature-sidebar{position:fixed;top:12px;bottom:12px;left:12px;z-index:1000;width:270px;padding:14px;display:flex;flex-direction:column;gap:10px;overflow:hidden;transform:translateX(calc(-100% - 24px));background:var(--surface);border:1px solid var(--border-strong);border-radius:20px;box-shadow:18px 20px 50px rgba(0,0,0,.48);transition:none}.feature-sidebar.is-open{transform:translateX(0)}.sidebar-head{display:flex;align-items:center;justify-content:space-between;padding:2px 2px 11px;border-bottom:1px solid var(--border)}.sidebar-title{color:var(--text-primary);font-size:14px;font-weight:600}.sidebar-close{width:32px;height:32px;border:1px solid var(--border-strong);border-radius:10px;background:var(--surface);color:var(--text-primary);cursor:pointer}.feature-list{display:grid;gap:8px;overflow:auto}.feature-item{width:100%;min-height:44px;padding:0 13px;display:flex;align-items:center;gap:10px;border:1px solid var(--border-strong);border-radius:14px;background:var(--surface);color:var(--text-primary);font:600 .78rem Inter,sans-serif;cursor:pointer;text-align:left;transition:background .18s ease,border-color .18s ease,box-shadow .18s ease}.feature-item i{width:18px;display:inline-flex;justify-content:center;color:var(--text-secondary)}.feature-item:hover,.feature-item.active{border-color:var(--text-primary);background:var(--surface-2);box-shadow:0 5px 14px rgba(0,0,0,.16)}.about-panel{padding:12px;border:1px solid var(--border-strong);border-radius:14px;background:var(--surface-2);color:var(--text-secondary);font-size:12px;line-height:1.5}.about-panel[hidden]{display:none}.about-panel-head{display:flex;align-items:center;gap:8px;margin-bottom:7px;color:var(--text-primary);font-size:13px;font-weight:700}.about-panel-head i{color:var(--text-secondary)}.about-panel p{margin:0}.about-panel strong{color:var(--text-primary);font-weight:700}
.engine-panel{min-height:0;overflow:auto;padding:12px;border:1px solid var(--border-strong);border-radius:16px;background:var(--surface-2);color:var(--text-primary)}.engine-panel[hidden]{display:none}.engine-panel-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:10px;font-size:13px}.engine-panel-head button{width:26px;height:26px;border:1px solid var(--border);border-radius:8px;background:var(--surface);color:var(--text-primary);font-size:17px;cursor:pointer}.engine-status{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px;padding:8px 9px;border-radius:10px;background:var(--surface);font-size:11px;color:var(--text-secondary)}.engine-status strong{color:var(--text-primary)}.engine-section{margin-top:10px;padding-top:10px;border-top:1px solid var(--border)}.engine-section[hidden]{display:none}.engine-label{margin-bottom:7px;color:var(--text-primary);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.05em}.engine-chips{display:grid;grid-template-columns:repeat(3,1fr);gap:6px}.engine-chips button,.engine-actions button,.segmented button{min-height:34px;padding:5px 7px;border:1px solid var(--border-strong);border-radius:9px;background:var(--surface);color:var(--text-primary);font:600 10px Inter,sans-serif;cursor:pointer}.engine-chips button:hover,.engine-actions button:hover,.segmented button:hover{background:var(--button-light);color:var(--button-light-text)}.segmented{display:grid;grid-template-columns:repeat(3,1fr);gap:5px}.segmented button.active{background:var(--button-light);color:var(--button-light-text);border-color:var(--text-primary)}.engine-actions{display:grid;grid-template-columns:repeat(2,1fr);gap:6px}.engine-panel textarea,.matrix-grid input{width:100%;border:1px solid var(--border-strong);border-radius:9px;background:var(--surface);color:var(--text-primary);padding:8px;font:500 11px Inter,sans-serif;outline:none}.engine-panel textarea:focus,.matrix-grid input:focus{border-color:var(--text-primary)}.matrix-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:5px;margin-bottom:6px}.engine-output{margin-top:7px;padding:8px;border-radius:9px;background:var(--surface);color:var(--text-secondary);font:500 10px/1.4 ui-monospace,SFMono-Regular,monospace;overflow:auto}.engine-help,.engine-about p{color:var(--text-secondary);font-size:10px;line-height:1.45;margin-bottom:8px}.engine-primary{width:100%;min-height:34px;border:1px solid var(--border-strong);border-radius:9px;background:var(--button-light);color:var(--button-light-text);font:700 10px Inter,sans-serif;cursor:pointer}
body.sidebar-visible .container-fluid{transform:translateX(115px)}@media(max-width:700px){.container-fluid{padding:14px}body.sidebar-visible .container-fluid{transform:none}}@media(max-width:480px){.container-fluid{padding:10px}.calculator-container{width:min(100%,390px)}.calculator{padding:14px;border-radius:27px}.display-container{min-height:126px;margin-bottom:15px}.btn{height:58px;font-size:1.12rem;border-radius:17px}.sidebar-open{top:14px;right:14px}.feature-sidebar{width:min(300px,calc(100vw - 24px))}}@media(max-width:370px){.calculator{padding:12px}.display-container{min-height:112px}.display-primary{font-size:2.2rem}.button-grid{gap:8px}.btn{height:52px;border-radius:16px}}@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}}