:root{
  --bg: #f4efe6; /* warm, light parchment */
  --surface: #fffdfb;
  --muted: #7a6b5a; /* soft brown-gray */
  --accent: #3b2f2a; /* deep espresso */
  --primary: linear-gradient(90deg,#8b5e3c,#b86e45); /* terracotta -> warm clay */
  --primary-plain: #8b5e3c; /* fallback single color */
  --accent-soft: #f0e8de;
  --gap: 28px;
  --pad: 22px;
  --radius: 16px;
  --card-shadow: 0 10px 30px rgba(27,23,20,0.08);
  --glass: rgba(255,255,255,0.6);
  --font-sans: Inter, system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
html,body{height:100%}
body{
  margin:0;
  font-family:var(--font-sans);
  background:linear-gradient(180deg,var(--bg),#efe8dd 70%),radial-gradient(circle at 20% 50%,rgba(139,94,60,0.03) 1px,transparent 1px),radial-gradient(circle at 80% 80%,rgba(139,94,60,0.03) 1px,transparent 1px);
  background-size:100% 100%, 24px 24px, 24px 24px;
  background-position:0 0, 0 0, 12px 12px;
  color:var(--accent);
  -webkit-font-smoothing:antialiased;
  font-size:clamp(15px,1vw + 0.5rem,18px);line-height:1.5;
}

.app-header{
  height:110px;display:flex;align-items:center;justify-content:space-between;padding:0 28px;max-width:1200px;margin:0 auto
}
.header-controls{display:flex;align-items:center;gap:14px}
.header-controls label{color:var(--muted);font-weight:600;font-size:0.9rem}
#backend-toggle{padding:10px 14px;border:1px solid rgba(27,23,20,0.06);border-radius:10px;background:rgba(255,255,255,0.98);outline:none;cursor:pointer;font-family:var(--font-sans);font-weight:600;color:var(--accent);transition:box-shadow .15s ease,border-color .12s ease,transform .12s ease}
#backend-toggle:focus{box-shadow:0 8px 20px rgba(27,23,20,0.06);border-color:rgba(139,94,60,0.18);transform:translateY(-1px)}
#backend-toggle:hover{border-color:rgba(139,94,60,0.12)}
.logo-top{text-align:center;padding:20px 0 12px;background:linear-gradient(90deg, rgba(139,94,60,0.06), rgba(0,0,0,0.02))}
.logo-img-main{height:90px;width:auto;display:inline-block;animation:logoFloat 3s ease-in-out infinite;transition:transform .18s ease}
.logo-img-main:hover{transform:scale(1.05)}
@keyframes logoFloat{0%,100%{transform:translateY(0)}50%{transform:translateY(-8px)}}
.logo-img{height:68px;width:auto;display:block;transition:transform .18s ease}
.logo-img:hover{transform:scale(1.03)}

.app{max-width:1200px;margin:34px auto;display:grid;grid-template-columns:460px 1fr;gap:var(--gap);padding:0 20px;transition:grid-template-columns .3s ease}
.app.comparison-mode{grid-template-columns:1fr 1fr 1fr}
.app.comparison-mode .result-panel{grid-column:3}

#comparison-panel{display:none}
.app.comparison-mode #comparison-panel{display:block}

/* Comparison result styling */
.comparison-result{margin-top:20px;padding-top:16px;border-top:2px solid rgba(139,94,60,0.1)}
.comparison-result h3{font-size:16px;margin:0 0 8px;color:var(--muted)}

.card{
  background:linear-gradient(135deg,rgba(255,255,255,0.95),rgba(255,250,248,0.92));
  padding:calc(var(--pad) + 2px);
  border-radius:var(--radius);
  box-shadow:var(--card-shadow),inset 0 1px 0 rgba(255,255,255,0.6);
  border:1px solid rgba(255,255,255,0.4);
  backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);
  transition:transform .24s cubic-bezier(.2,.9,.3,1),box-shadow .24s ease,backdrop-filter .24s ease;
}
.card:hover{transform:translateY(-8px) scale(1.01);box-shadow:0 24px 48px rgba(27,23,20,0.12),inset 0 1px 0 rgba(255,255,255,0.8);backdrop-filter:blur(16px)}

.calc-panel h2{font-size:22px;margin:0 0 6px 0;letter-spacing:0.2px}
.calc-panel p.sub{margin:8px 0 18px;color:var(--muted);font-size:0.95rem}

.field{margin-bottom:14px;position:relative}
.field label{transition:color .2s ease,transform .2s ease;display:inline-block}
.field:focus-within label{color:var(--primary-plain);transform:translateX(2px)}
.input{
  width:100%;padding:14px;border:1px solid rgba(27,23,20,0.06);border-radius:12px;background:rgba(255,255,255,0.98);outline:none;transition:box-shadow .2s cubic-bezier(.2,.9,.3,1), border-color .15s ease, transform .2s cubic-bezier(.2,.9,.3,1), box-shadow .2s ease;position:relative
}
.input:focus{box-shadow:0 0 0 3px rgba(139,94,60,0.12),0 12px 30px rgba(27,23,20,0.08),0 0 20px rgba(139,94,60,0.15);border-color:rgba(139,94,60,0.4);transform:translateY(-2px) scale(1.005);animation:inputGlow 1.5s ease-in-out infinite}
.input:hover:not(:focus){border-color:rgba(139,94,60,0.12);transform:translateY(-1px);box-shadow:0 4px 12px rgba(27,23,20,0.06)}
.input.error{border-color:#ffd7d0;background:#fff6f6;animation:shake .4s ease}
@keyframes inputGlow{0%,100%{box-shadow:0 0 0 3px rgba(139,94,60,0.12),0 12px 30px rgba(27,23,20,0.08),0 0 20px rgba(139,94,60,0.15)}50%{box-shadow:0 0 0 3px rgba(139,94,60,0.18),0 12px 30px rgba(27,23,20,0.12),0 0 30px rgba(139,94,60,0.25)}}
@keyframes shake{0%,100%{transform:translateX(0)}25%{transform:translateX(-8px)}75%{transform:translateX(8px)}}
.help-text{color:var(--muted);font-size:0.92rem;margin-top:6px}
.error-message{color:#d9534f;font-size:0.9rem;margin-top:6px}

.actions{display:flex;gap:12px;align-items:center}
.btn-primary{
  background:transparent;
  color:var(--primary-plain);
  border:3px solid transparent;
  background-image:linear-gradient(var(--surface),var(--surface)),linear-gradient(90deg,#8b5e3c,#b86e45,#8b5e3c);
  background-origin:border-box;
  background-clip:padding-box,border-box;
  padding:12px 20px;border-radius:999px;cursor:pointer;font-weight:700;letter-spacing:0.6px;text-transform:uppercase;
  box-shadow:0 10px 30px rgba(139,94,60,0.06);
  transition:transform .2s cubic-bezier(.2,.9,.3,1),box-shadow .2s ease,filter .15s ease;
  position:relative;overflow:hidden;
}
.btn-primary:hover{transform:translateY(-4px) scale(1.03);box-shadow:0 0 0 4px rgba(139,94,60,0.06),0 20px 48px rgba(139,94,60,0.16);filter:brightness(1.04);background-image:linear-gradient(#8b5e3c,#8b5e3c),linear-gradient(90deg,#8b5e3c,#b86e45,#8b5e3c);color:#fff}
.btn-primary:active{transform:translateY(-1px) scale(0.98)}

.btn-ghost{background:rgba(255,255,255,0.6);border:1px solid rgba(27,23,20,0.08);padding:10px 16px;border-radius:12px;cursor:pointer;transition:transform .15s cubic-bezier(.2,.9,.3,1),background-color .15s ease,box-shadow .15s ease,border-color .15s ease;backdrop-filter:blur(4px)}
.btn-ghost:hover{background:var(--accent-soft);transform:translateY(-3px) scale(1.02);box-shadow:0 8px 20px rgba(27,23,20,0.08);border-color:rgba(139,94,60,0.12)}
.btn-ghost:active{transform:translateY(-1px) scale(0.98)}

/* About INIYE AI button - highlighted and prominent */
.btn-about{
  background:linear-gradient(135deg,#8b5e3c 0%,#b86e45 100%);
  border:2px solid rgba(255,255,255,0.3);
  padding:12px 24px;
  border-radius:16px;
  cursor:pointer;
  font-size:1.05rem;
  font-weight:700;
  color:#fff;
  text-shadow:0 1px 2px rgba(0,0,0,0.2);
  box-shadow:0 4px 16px rgba(139,94,60,0.3),0 0 0 1px rgba(139,94,60,0.1),inset 0 1px 0 rgba(255,255,255,0.2);
  transition:transform .2s cubic-bezier(.2,.9,.3,1),box-shadow .2s ease,border-color .2s ease;
  backdrop-filter:blur(8px);
  position:relative;
  overflow:hidden
}
.btn-about::before{
  content:'';
  position:absolute;
  top:0;
  left:-100%;
  width:100%;
  height:100%;
  background:linear-gradient(90deg,transparent,rgba(255,255,255,0.3),transparent);
  transition:left .6s ease
}
.btn-about:hover::before{left:100%}
.btn-about:hover{
  transform:translateY(-4px) scale(1.05);
  box-shadow:0 8px 32px rgba(139,94,60,0.4),0 0 0 3px rgba(139,94,60,0.15),inset 0 1px 0 rgba(255,255,255,0.3);
  border-color:rgba(255,255,255,0.5)
}
.btn-about:active{transform:translateY(-2px) scale(1.02)}

.result-panel{display:flex;flex-direction:column;gap:12px}
.result-value{font-size:clamp(28px,4vw,40px);font-weight:800;margin-top:8px;color:var(--accent);transition:transform .3s cubic-bezier(.2,.9,.3,1),color .2s ease}
.result-value:not(:empty):hover{transform:scale(1.02);color:var(--primary-plain)}
.result-json{background:#0f172a;color:#fff;padding:12px;border-radius:12px;overflow:auto}
.result-actions{margin-top:6px;display:flex;gap:8px}

@media(max-width:900px){.app{grid-template-columns:1fr;padding:12px}}
@media(max-width:1200px){.app.comparison-mode{grid-template-columns:1fr;padding:12px}.app.comparison-mode .result-panel{grid-column:1}}

/* Range sliders */
input[type="range"]{width:100%;height:8px;border-radius:4px;background:linear-gradient(90deg,rgba(139,94,60,0.2),rgba(184,110,69,0.4));outline:none;-webkit-appearance:none;appearance:none}
input[type="range"]::-webkit-slider-thumb{-webkit-appearance:none;appearance:none;width:20px;height:20px;border-radius:50%;background:linear-gradient(135deg,#8b5e3c,#b86e45);cursor:pointer;box-shadow:0 4px 12px rgba(139,94,60,0.3);transition:transform .15s ease}
input[type="range"]::-webkit-slider-thumb:hover{transform:scale(1.2)}
input[type="range"]::-moz-range-thumb{width:20px;height:20px;border-radius:50%;background:linear-gradient(135deg,#8b5e3c,#b86e45);cursor:pointer;box-shadow:0 4px 12px rgba(139,94,60,0.3);border:none;transition:transform .15s ease}
input[type="range"]::-moz-range-thumb:hover{transform:scale(1.2)}
.slider-value{display:inline-block;min-width:80px;text-align:right;font-weight:600;color:var(--primary-plain);margin-left:8px}

/* Sensitivity analysis table */
#sensitivity-container{background:rgba(255,255,255,0.5);padding:16px;border-radius:12px;border:1px solid rgba(139,94,60,0.08)}
#sensitivity-container h3{margin:0 0 12px;font-size:18px;color:var(--accent)}
#sensitivity-table{overflow-x:auto}
.sensitivity-table{width:100%;border-collapse:collapse;font-size:0.9rem}
.sensitivity-table th,.sensitivity-table td{padding:10px;text-align:right;border-bottom:1px solid rgba(139,94,60,0.08)}
.sensitivity-table th{background:rgba(139,94,60,0.06);font-weight:700;color:var(--accent);position:sticky;top:0}
.sensitivity-table td{color:var(--accent)}
.sensitivity-table tr:hover{background:rgba(139,94,60,0.03)}
.sensitivity-table .highlight{background:rgba(139,94,60,0.12);font-weight:700}

/* Loading clock animation (modern ticking clock) */
.spinner{display:inline-block;width:24px;height:24px;border:2px solid rgba(27,23,20,0.08);border-radius:50%;position:relative;vertical-align:middle;margin-left:8px}
.spinner::before,.spinner::after{content:'';position:absolute;background:var(--accent);border-radius:2px;transform-origin:bottom center}
.spinner::before{width:2px;height:8px;left:50%;top:20%;margin-left:-1px;animation:tickHour 2s linear infinite}
.spinner::after{width:1.5px;height:10px;left:50%;top:10%;margin-left:-0.75px;animation:tickMinute 1s steps(12) infinite}
@keyframes tickHour{0%{transform:rotate(0deg)}100%{transform:rotate(360deg)}}
@keyframes tickMinute{0%{transform:rotate(0deg)}100%{transform:rotate(360deg)}}

.visually-hidden{position:absolute!important;height:1px;width:1px;overflow:hidden;clip:rect(1px,1px,1px,1px);white-space:nowrap}

/* Keyboard help button */
.btn-icon{background:rgba(139,94,60,0.08);border:1px solid rgba(139,94,60,0.12);width:28px;height:28px;border-radius:50%;cursor:pointer;font-weight:700;font-size:14px;margin-left:8px;transition:transform .15s ease,background-color .15s ease;vertical-align:middle}
.btn-icon:hover{background:rgba(139,94,60,0.14);transform:scale(1.1)}

/* Formula tooltip */
.formula-tooltip{margin-top:8px;padding:10px;background:rgba(139,94,60,0.06);border-left:3px solid var(--primary-plain);border-radius:6px;font-size:0.88rem;color:var(--muted);font-family:monospace;display:none}
.formula-tooltip.show{display:block}

/* History sidebar */
.history-sidebar{position:fixed;right:0;top:0;width:360px;height:100vh;background:linear-gradient(135deg,rgba(255,255,255,0.98),rgba(255,250,248,0.95));backdrop-filter:blur(16px);box-shadow:-4px 0 24px rgba(27,23,20,0.12);transform:translateX(100%);transition:transform .3s cubic-bezier(.2,.9,.3,1);z-index:1000;overflow-y:auto;padding:20px;display:block}
.history-sidebar[hidden]{transform:translateX(100%);pointer-events:none}
.history-sidebar:not([hidden]){transform:translateX(0);pointer-events:auto}
.history-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;padding-bottom:12px;border-bottom:2px solid rgba(139,94,60,0.1)}
.history-header h3{margin:0;font-size:18px;color:var(--accent)}
.history-list{display:flex;flex-direction:column;gap:10px}
.history-item{background:rgba(255,255,255,0.8);border:1px solid rgba(27,23,20,0.06);border-radius:10px;padding:12px;cursor:pointer;transition:transform .12s ease,box-shadow .12s ease}
.history-item:hover{transform:translateX(-4px);box-shadow:0 6px 16px rgba(27,23,20,0.08)}
.history-item-op{font-weight:700;color:var(--primary-plain);margin-bottom:4px;font-size:0.9rem}
.history-item-result{font-size:1.1rem;font-weight:600;color:var(--accent)}
.history-item-time{font-size:0.8rem;color:var(--muted);margin-top:4px}

/* Dark mode */
.theme-dark{
  --bg: #0f1419;
  --surface: #1a1f26;
  --muted: #8b949e;
  --accent: #e6edf3;
  --primary-plain: #b86e45;
  --accent-soft: #21262d;
  --card-shadow: 0 8px 28px rgba(0,0,0,0.4);
}
.theme-dark .card{background:linear-gradient(135deg,rgba(26,31,38,0.98),rgba(33,38,45,0.95));border-color:rgba(255,255,255,0.08)}
.theme-dark .input{background:rgba(33,38,45,0.8);border-color:rgba(255,255,255,0.08);color:#e6edf3}
.theme-dark .btn-primary{background-image:linear-gradient(#1a1f26,#1a1f26),linear-gradient(90deg,#b86e45,#d88a5e,#b86e45)}
.theme-dark .btn-ghost{background:rgba(33,38,45,0.6);border-color:rgba(255,255,255,0.08)}
.theme-dark .btn-about{
  background:linear-gradient(135deg,#b86e45 0%,#d88a5e 100%);
  border-color:rgba(255,255,255,0.4);
  box-shadow:0 4px 16px rgba(184,110,69,0.4),0 0 0 1px rgba(184,110,69,0.2),inset 0 1px 0 rgba(255,255,255,0.25)
}
.theme-dark .btn-about:hover{
  box-shadow:0 8px 32px rgba(184,110,69,0.5),0 0 0 3px rgba(184,110,69,0.25),inset 0 1px 0 rgba(255,255,255,0.3)
}
.theme-dark .toast{background:linear-gradient(135deg,rgba(184,110,69,0.95),rgba(216,138,94,0.93))}

/* Print styles */
@media print{
  .app-header,.hero,.history-sidebar,.btn-ghost,#toggleHistory,.theme-icon{display:none!important}
  .card{box-shadow:none;border:1px solid #ccc;page-break-inside:avoid}
  body{background:white}
  .result-value{font-size:24px}
}

/* Info Modal */
.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,0.6);backdrop-filter:blur(8px);z-index:2000;display:flex;align-items:center;justify-content:center;opacity:0;transition:opacity .2s ease}
.modal-overlay.show{opacity:1}
.modal-overlay.modal-exit{opacity:0}
.modal-content{background:linear-gradient(135deg,rgba(255,255,255,0.98),rgba(255,250,248,0.95));backdrop-filter:blur(20px);max-width:600px;width:90%;max-height:80vh;overflow-y:auto;border-radius:16px;box-shadow:0 20px 60px rgba(27,23,20,0.3);padding:32px;position:relative;transform:scale(0.9);transition:transform .2s ease}
.modal-overlay.show .modal-content{transform:scale(1)}
.modal-close{position:absolute;top:16px;right:16px;background:rgba(139,94,60,0.08);border:1px solid rgba(139,94,60,0.12);width:32px;height:32px;border-radius:50%;cursor:pointer;font-weight:700;font-size:24px;line-height:28px;transition:transform .15s ease,background-color .15s ease;color:var(--accent)}
.modal-close:hover{background:rgba(139,94,60,0.14);transform:scale(1.1)}
.modal-body{margin-top:16px}
.modal-body h3{margin:20px 0 12px;color:var(--primary-plain);font-size:1.1rem}
.modal-body p{line-height:1.6;color:var(--accent);margin:12px 0}
.modal-body ul{margin:12px 0;padding-left:24px;line-height:1.8}
.modal-body li{margin:8px 0;color:var(--accent)}
.modal-body strong{color:var(--primary-plain)}
.modal-body kbd{background:rgba(139,94,60,0.08);padding:3px 8px;border-radius:4px;font-family:monospace;font-size:0.9em;border:1px solid rgba(139,94,60,0.12)}

/* Footer Hero */
.footer-hero{margin-top:60px;padding:40px 20px;background:linear-gradient(135deg,rgba(255,255,255,0.95),rgba(255,250,248,0.92)),radial-gradient(circle at 50% 50%,rgba(139,94,60,0.03) 1px,transparent 1px);background-size:100% 100%, 32px 32px;backdrop-filter:blur(12px);border-top:1px solid rgba(139,94,60,0.08);position:relative}
.footer-hero::before{content:'';position:absolute;top:0;left:0;right:0;height:1px;background:linear-gradient(90deg,transparent,rgba(139,94,60,0.3) 50%,transparent)}
.footer-content{max-width:1200px;margin:0 auto;display:flex;flex-direction:column;align-items:center;gap:16px}
.footer-text{display:flex;align-items:center;gap:12px;flex-wrap:wrap;justify-content:center;font-size:1.1rem}
.footer-title{font-weight:700;color:var(--accent);letter-spacing:1px}
.footer-powered{color:var(--muted);font-size:0.95rem;font-weight:400}
.footer-logo{height:48px;width:auto;display:inline-block;vertical-align:middle;animation:logoFloatFooter 4s ease-in-out infinite;filter:drop-shadow(0 2px 8px rgba(139,94,60,0.2));transition:transform .3s ease}
.footer-logo:hover{transform:scale(1.08);animation-play-state:paused}
@keyframes logoFloatFooter{0%,100%{transform:translateY(0) rotate(0deg)}25%{transform:translateY(-4px) rotate(1deg)}50%{transform:translateY(0) rotate(0deg)}75%{transform:translateY(-4px) rotate(-1deg)}}
.footer-copyright{font-size:0.85rem;color:var(--muted);display:flex;align-items:center;gap:6px}
.footer-copyright::before{content:'©';font-size:1rem;font-weight:700}

/* Toast notifications */
.toast-container{position:fixed;top:20px;right:20px;z-index:9999;pointer-events:none}
.toast{background:linear-gradient(135deg,rgba(139,94,60,0.98),rgba(184,110,69,0.96));color:#fff;padding:16px 24px;border-radius:12px;box-shadow:0 12px 40px rgba(27,23,20,0.25),inset 0 1px 0 rgba(255,255,255,0.3);margin-bottom:12px;min-width:280px;pointer-events:auto;backdrop-filter:blur(12px);animation:toastSlideIn .3s cubic-bezier(.2,.9,.3,1);font-weight:600;display:flex;align-items:center;gap:12px}
.toast.toast-exit{animation:toastSlideOut .25s ease forwards}
.toast-icon{font-size:20px}
@keyframes toastSlideIn{from{transform:translateX(400px);opacity:0}to{transform:translateX(0);opacity:1}}
@keyframes toastSlideOut{to{transform:translateX(400px);opacity:0}}

/* Theme modifiers: warm is default, cool adjusts tones */
.theme-cool{
  --bg: #eef6fb;
  --surface: #fbfdff;
  --muted: #6b7280;
  --accent: #0f172a;
  --primary-plain: #0b5fff;
  --accent-soft: #eaf2ff;
  --card-shadow: 0 8px 28px rgba(6,22,52,0.06);
}

/* Hero header */
.hero{background:linear-gradient(90deg, rgba(139,94,60,0.06), rgba(0,0,0,0.02)),repeating-linear-gradient(45deg,transparent,transparent 10px,rgba(139,94,60,0.015) 10px,rgba(139,94,60,0.015) 20px);padding:38px 0;border-bottom:1px solid rgba(27,23,20,0.03)}
.hero-inner{max-width:1200px;margin:0 auto;padding:0 20px}
.hero-title{margin:0;font-size:clamp(32px,5vw,48px);letter-spacing:clamp(2px,0.3vw,4px);color:var(--accent);font-weight:900;transition:text-shadow .3s ease,transform .3s cubic-bezier(.2,.9,.3,1);cursor:default}
.hero-title:hover{text-shadow:0 0 40px rgba(139,94,60,0.4),0 0 80px rgba(139,94,60,0.2),0 4px 12px rgba(139,94,60,0.15);transform:scale(1.02)}
.hero-sub{margin:10px 0 0;color:var(--muted);font-size:0.88rem;font-weight:400}

/* Theme toggle icon (dynamic color: black for warm, white for cool) */
#theme-toggle{display:inline-flex;align-items:center;gap:8px}
#theme-toggle .theme-icon{display:inline-block;width:14px;height:14px;border-radius:50%;background:#111;flex:0 0 14px;transition:background-color .2s ease,transform .2s ease}
.theme-cool #theme-toggle .theme-icon{background:#fff;box-shadow:0 0 0 1px rgba(0,0,0,0.1)}
#theme-toggle .theme-label{font-weight:600;color:var(--accent);font-size:0.95rem}
#theme-toggle:hover .theme-icon{transform:scale(1.08)}

/* Success Toast Notification */
.toast{position:fixed;top:20px;right:20px;background:linear-gradient(135deg,#4caf50,#45a049);color:#fff;padding:16px 24px;border-radius:12px;box-shadow:0 8px 24px rgba(76,175,80,0.4);z-index:2000;transform:translateX(400px);transition:transform .3s cubic-bezier(.2,.9,.3,1);font-weight:600;display:flex;align-items:center;gap:12px}
.toast.show{transform:translateX(0)}
.toast::before{content:'✓';font-size:20px;font-weight:700}

/* Progress Bar */
.progress-bar{position:fixed;top:0;left:0;width:100%;height:3px;background:rgba(139,94,60,0.1);z-index:1999;overflow:hidden}
.progress-bar-fill{height:100%;background:linear-gradient(90deg,#8b5e3c,#b86e45,#8b5e3c);background-size:200% 100%;animation:progressSlide 1.5s ease-in-out;transform-origin:left;transition:width .3s ease}
@keyframes progressSlide{0%{background-position:0% 0%}100%{background-position:200% 0%}}

/* Result Animation */
.result-value{animation:none}
.result-value.animate-in{animation:resultFadeIn .5s cubic-bezier(.2,.9,.3,1)}
@keyframes resultFadeIn{0%{opacity:0;transform:translateY(20px) scale(0.95)}100%{opacity:1;transform:translateY(0) scale(1)}}

/* Enhanced Empty State */
.result-value:empty::after{content:'Awaiting calculation...';font-size:18px;color:var(--muted);font-weight:400;font-style:italic;opacity:0.6}

/* Tooltips */
.tooltip{position:absolute;background:rgba(59,47,42,0.95);color:#fff;padding:8px 12px;border-radius:8px;font-size:13px;white-space:nowrap;z-index:1000;pointer-events:none;opacity:0;transform:translateY(-5px);transition:opacity .2s ease,transform .2s ease;box-shadow:0 4px 12px rgba(0,0,0,0.2)}
.tooltip.show{opacity:1;transform:translateY(0)}
.tooltip::after{content:'';position:absolute;top:100%;left:50%;transform:translateX(-50%);border:6px solid transparent;border-top-color:rgba(59,47,42,0.95)}

/* Field Separators */
.field-separator{height:1px;background:linear-gradient(90deg,transparent,rgba(139,94,60,0.15),transparent);margin:24px 0;position:relative}
.field-separator[data-label]::after{content:attr(data-label);position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);background:var(--surface);padding:0 12px;font-size:11px;font-weight:700;letter-spacing:1px;color:var(--muted);opacity:0.7}

/* Required Field Indicator */
.field.required label::after{content:'*';color:#d9534f;margin-left:4px;font-weight:700}

/* Ripple Effect */
.btn-primary,.btn-ghost,.btn-about{position:relative;overflow:hidden}
.ripple{position:absolute;border-radius:50%;background:rgba(255,255,255,0.6);transform:scale(0);animation:rippleEffect .6s ease-out}
@keyframes rippleEffect{to{transform:scale(4);opacity:0}}

/* Enhanced Input Focus with Glow */
.input:focus{box-shadow:0 0 0 3px rgba(139,94,60,0.08),0 12px 30px rgba(27,23,20,0.08),0 0 20px rgba(139,94,60,0.15);border-color:rgba(139,94,60,0.3);transform:translateY(-2px) scale(1.005)}

/* Smooth Theme Transition */
body,body *{transition:background-color .3s ease,color .3s ease,border-color .3s ease}

/* Chart Animation */
#chart{opacity:1;transition:opacity .5s ease}
#chart.chart-appear{animation:chartFadeIn .6s cubic-bezier(.2,.9,.3,1)}
@keyframes chartFadeIn{0%{opacity:0;transform:translateY(20px) scale(0.98)}100%{opacity:1;transform:translateY(0) scale(1)}}

/* Icon Indicators for Operations */
.optgroup-icon{font-size:14px;margin-right:6px}

/* Toast notification system */
.toast-container{position:fixed;top:20px;right:20px;z-index:10000;display:flex;flex-direction:column;gap:12px;pointer-events:none}
.toast{
  background:linear-gradient(135deg,rgba(139,94,60,0.95),rgba(184,110,69,0.93));
  color:#fff;
  padding:16px 24px;
  border-radius:12px;
  box-shadow:0 8px 32px rgba(27,23,20,0.25),0 0 0 1px rgba(255,255,255,0.2);
  backdrop-filter:blur(12px);
  font-weight:600;
  font-size:0.95rem;
  pointer-events:auto;
  transform:translateX(400px);
  opacity:0;
  transition:transform .4s cubic-bezier(.2,.9,.3,1),opacity .4s ease;
  display:flex;
  align-items:center;
  gap:12px
}
.toast.show{transform:translateX(0);opacity:1}
.toast.hide{transform:translateX(400px);opacity:0}
.toast::before{content:'✓';font-size:1.3rem;font-weight:700}
.toast-success{background:linear-gradient(135deg,rgba(40,167,69,0.95),rgba(56,193,89,0.93))}
.toast-error{background:linear-gradient(135deg,rgba(220,53,69,0.95),rgba(217,83,79,0.93))}

/* Enhanced result display with animations */
.result-value{
  font-size:clamp(28px,4vw,40px);
  font-weight:800;
  margin-top:8px;
  color:var(--accent);
  transition:transform .3s cubic-bezier(.2,.9,.3,1),color .2s ease,opacity .3s ease;
  animation:resultFadeIn .6s cubic-bezier(.2,.9,.3,1)
}
.result-value:not(:empty):hover{transform:scale(1.02);color:var(--primary-plain)}
.result-value.calculating{opacity:0.5;animation:pulse 1.5s ease-in-out infinite}
@keyframes resultFadeIn{0%{opacity:0;transform:translateY(20px) scale(0.95)}100%{opacity:1;transform:translateY(0) scale(1)}}
@keyframes pulse{0%,100%{opacity:0.5}50%{opacity:0.8}}

/* Required field indicators */
.field.required label::after{content:'*';color:#d9534f;margin-left:4px;font-weight:700}
.field.required .input{border-left:3px solid rgba(217,83,79,0.3)}
.field.required .input:focus{border-left-color:#d9534f}

/* Enhanced button ripple effects */
.btn-primary,.btn-ghost,.btn-about{position:relative;overflow:hidden}
.btn-primary::after,.btn-ghost::after,.btn-about::after{
  content:'';
  position:absolute;
  top:50%;
  left:50%;
  width:0;
  height:0;
  border-radius:50%;
  background:rgba(255,255,255,0.4);
  transform:translate(-50%,-50%);
  transition:width .6s ease,height .6s ease,opacity .6s ease;
  opacity:0;
  pointer-events:none
}
.btn-primary:active::after,.btn-ghost:active::after,.btn-about:active::after{
  width:300px;
  height:300px;
  opacity:1;
  transition:width 0s,height 0s,opacity 0s
}

/* Chart animations */
#chart{transition:opacity .4s ease,transform .4s cubic-bezier(.2,.9,.3,1)}
#chart.chart-appear{animation:chartSlideIn .6s cubic-bezier(.2,.9,.3,1)}
@keyframes chartSlideIn{0%{opacity:0;transform:translateY(30px) scale(0.95)}100%{opacity:1;transform:translateY(0) scale(1)}}

/* Visual separators between field groups */
.field-separator{
  height:1px;
  background:linear-gradient(90deg,transparent,rgba(139,94,60,0.15) 20%,rgba(139,94,60,0.15) 80%,transparent);
  margin:20px 0;
  position:relative
}
.field-separator::before{
  content:attr(data-label);
  position:absolute;
  top:50%;
  left:50%;
  transform:translate(-50%,-50%);
  background:var(--surface);
  padding:0 12px;
  color:var(--muted);
  font-size:0.85rem;
  font-weight:600;
  letter-spacing:0.5px
}

/* Enhanced tooltips */
.tooltip{
  position:absolute;
  background:rgba(27,23,20,0.95);
  color:#fff;
  padding:8px 12px;
  border-radius:8px;
  font-size:0.85rem;
  white-space:nowrap;
  z-index:1000;
  pointer-events:none;
  opacity:0;
  transform:translateY(-8px);
  transition:opacity .2s ease,transform .2s ease;
  box-shadow:0 4px 16px rgba(0,0,0,0.25)
}
.tooltip.show{opacity:1;transform:translateY(0)}
.tooltip::after{
  content:'';
  position:absolute;
  top:100%;
  left:50%;
  transform:translateX(-50%);
  border:6px solid transparent;
  border-top-color:rgba(27,23,20,0.95)
}

/* Progress indicator */
.progress-bar{
  position:fixed;
  top:0;
  left:0;
  width:0;
  height:3px;
  background:linear-gradient(90deg,#8b5e3c,#b86e45,#8b5e3c);
  z-index:10000;
  transition:width .3s ease;
  box-shadow:0 0 10px rgba(139,94,60,0.6)
}
.progress-bar.active{animation:progressPulse 1.5s ease-in-out infinite}
@keyframes progressPulse{0%,100%{opacity:1}50%{opacity:0.7}}

/* Enhanced empty state */
.result-value:empty::before{
  content:'Ready to calculate';
  display:block;
  color:var(--muted);
  font-size:1.2rem;
  font-weight:600;
  opacity:0.6;
  animation:emptyStatePulse 3s ease-in-out infinite
}
@keyframes emptyStatePulse{0%,100%{opacity:0.6}50%{opacity:0.4}}
#theme-toggle .theme-icon.animate{animation:iconPulse .3s ease}
@keyframes iconPulse{0%,100%{transform:scale(1)}50%{transform:scale(1.3)}}