/* ===== Reset & Base ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg:#f4f6f9;--surface:#fff;--border:#e0e4ea;
  --text:#1a1d23;--text-secondary:#5f6570;--text-muted:#8b909a;
  --primary:#3b82f6;--primary-hover:#2563eb;--primary-light:#eff6ff;
  --success:#16a34a;--success-light:#f0fdf4;
  --warning:#d97706;--warning-light:#fffbeb;
  --danger:#dc2626;--danger-light:#fef2f2;
  --radius:8px;--radius-lg:12px;
  --shadow:0 1px 3px rgba(0,0,0,.06),0 1px 2px rgba(0,0,0,.04);
  --shadow-lg:0 4px 16px rgba(0,0,0,.08),0 2px 4px rgba(0,0,0,.04);
  --shadow-xl:0 8px 32px rgba(0,0,0,.12);
  --font:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;
  --mono:'SF Mono',SFMono-Regular,Consolas,'Liberation Mono',Menlo,monospace;
}
html{font-size:16px;-webkit-font-smoothing:antialiased}
body{font-family:var(--font);color:var(--text);background:var(--bg);line-height:1.5;min-height:100vh}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}

/* ===== Layout ===== */
.site-header{
  background:var(--surface);
  box-shadow:0 1px 4px rgba(0,0,0,.05);
  padding:.75rem 1.5rem;display:flex;align-items:center;gap:1rem;
  position:sticky;top:0;z-index:100;
}
.site-header .logo{font-size:1.125rem;font-weight:700;color:var(--text);white-space:nowrap}
.site-header .logo span{color:var(--primary)}
.site-header .search-box{
  flex:1;max-width:360px;margin-left:auto;
  position:relative;
}
.site-header .search-box input{
  width:100%;padding:.5rem .75rem .5rem 2.25rem;
  border:1px solid var(--border);border-radius:var(--radius);
  font-size:.875rem;background:var(--bg);
  transition:border-color .2s,box-shadow .2s;
}
.site-header .search-box input:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px rgba(59,130,246,.12)}
.site-header .search-box .search-icon{
  position:absolute;left:.65rem;top:50%;transform:translateY(-50%);
  color:var(--text-muted);font-size:.875rem;pointer-events:none;
}
.container{max-width:1080px;margin:0 auto;padding:1.5rem}

/* ===== Dashboard Grid ===== */
.category-section{margin-bottom:2rem}
.category-section h2{font-size:1rem;font-weight:600;color:var(--text-secondary);margin-bottom:.75rem;text-transform:uppercase;letter-spacing:.04em}
.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem}
.tool-card{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);
  padding:1.25rem;display:flex;flex-direction:column;gap:.5rem;
  transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease;cursor:pointer;
}
.tool-card:hover{
  transform:translateY(-2px);
  box-shadow:var(--shadow-xl);
  border-color:var(--primary);
}
.tool-card h3{font-size:1rem;font-weight:600}
.tool-card p{font-size:.8125rem;color:var(--text-secondary);flex:1}
.tool-card .open-btn{
  align-self:flex-start;margin-top:.25rem;
  padding:.375rem .875rem;border-radius:var(--radius);
  background:var(--primary-light);color:var(--primary);
  font-size:.8125rem;font-weight:600;border:none;cursor:pointer;
  transition:background .15s,color .15s;
}
.tool-card .open-btn:hover{background:var(--primary);color:#fff}

/* ===== Tool Page Layout ===== */
.tool-topbar{
  display:flex;align-items:center;gap:.75rem;flex-wrap:wrap;margin-bottom:1.25rem;
}
.tool-topbar .back-link{font-size:.8125rem;color:var(--text-secondary)}
.tool-topbar .back-link:hover{color:var(--primary)}
.tool-topbar h1{font-size:1.25rem;font-weight:700;flex:1}
.tool-topbar .btn-sm{
  padding:.35rem .75rem;border-radius:var(--radius);font-size:.8125rem;
  font-weight:500;border:1px solid var(--border);background:var(--surface);
  color:var(--text-secondary);cursor:pointer;transition:all .15s;
}
.tool-topbar .btn-sm:hover{border-color:var(--primary);color:var(--primary)}

/* ===== Cards ===== */
.card{
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius-lg);padding:1.25rem;margin-bottom:1rem;
  transition:box-shadow .2s;
}
.card:hover{box-shadow:var(--shadow)}
.card-title{
  font-size:.8125rem;font-weight:600;text-transform:uppercase;letter-spacing:.04em;
  color:var(--text-secondary);margin-bottom:1rem;
  padding-left:.75rem;border-left:3px solid var(--primary);
}

/* ===== Form Inputs ===== */
.input-grid{display:grid;grid-template-columns:1fr 1fr;gap:.75rem 1rem}
@media(max-width:600px){.input-grid{grid-template-columns:1fr}}
.field{display:flex;flex-direction:column;gap:.25rem}
.field label{font-size:.8125rem;font-weight:500;color:var(--text-secondary);display:flex;align-items:center;gap:.35rem}
.field label .tip{
  display:inline-flex;align-items:center;justify-content:center;
  width:15px;height:15px;border-radius:50%;
  background:var(--bg);border:1px solid var(--border);
  font-size:.625rem;font-weight:700;color:var(--text-muted);
  cursor:help;position:relative;
}
.field label .tip:hover::after{
  content:attr(data-tip);position:absolute;bottom:calc(100% + 6px);left:50%;
  transform:translateX(-50%);background:var(--text);color:#fff;
  font-size:.75rem;font-weight:400;padding:.35rem .6rem;border-radius:var(--radius);
  white-space:nowrap;z-index:10;pointer-events:none;
}
.field .input-row{display:flex;gap:.35rem}
.field input,.field select{
  padding:.5rem .65rem;border:1px solid var(--border);border-radius:var(--radius);
  font-size:.9rem;font-family:var(--font);background:var(--surface);
  transition:border-color .2s,box-shadow .2s;width:100%;
}
.field input:focus,.field select:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px rgba(59,130,246,.12)}
.field input.has-error{border-color:var(--danger)}
.field .unit-select{width:auto;min-width:80px;flex-shrink:0}
.field .error-msg{font-size:.75rem;color:var(--danger)}
.field-full{grid-column:1/-1}

/* ===== Buttons ===== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.4rem;
  padding:.6rem 1.25rem;border-radius:var(--radius);font-size:.875rem;
  font-weight:600;border:none;cursor:pointer;transition:all .15s;
}
.btn:active{transform:scale(.98)}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-hover)}
.btn-outline{background:transparent;border:1px solid var(--border);color:var(--text-secondary)}
.btn-outline:hover{border-color:var(--primary);color:var(--primary)}
.btn-group{display:flex;gap:.5rem;flex-wrap:wrap;margin-top:.75rem}

/* ===== Toggle / Mode Switch ===== */
.mode-switch{
  display:inline-flex;
  background:var(--bg);border:1px solid var(--border);
  border-radius:var(--radius-lg);overflow:hidden;
  padding:3px;
  margin-bottom:1rem;
}
.mode-switch button{
  padding:.45rem 1rem;font-size:.8125rem;font-weight:500;
  border:none;background:transparent;color:var(--text-secondary);cursor:pointer;
  transition:all .2s;border-radius:calc(var(--radius-lg) - 3px);
}
.mode-switch button.active{
  background:var(--primary);color:#fff;
  box-shadow:0 1px 3px rgba(0,0,0,.1);
}

/* ===== Advanced Options ===== */
.advanced-toggle{
  font-size:.8125rem;color:var(--text-muted);cursor:pointer;
  display:flex;align-items:center;gap:.35rem;margin-bottom:.75rem;
  background:none;border:none;font-family:var(--font);
}
.advanced-toggle .arrow{transition:transform .2s;display:inline-block}
.advanced-toggle.open .arrow{transform:rotate(90deg)}
.advanced-body{display:none}
.advanced-body.open{display:block}

/* ===== Result Card ===== */
.result-card{
  border-color:var(--primary);border-width:2px;
  border-left:4px solid var(--primary);
  background:linear-gradient(135deg,var(--surface) 0%,var(--primary-light) 100%);
  animation:slideUp .3s ease-out;
}
.result-card.hidden{display:none}
@keyframes slideUp{
  from{opacity:0;transform:translateY(12px)}
  to{opacity:1;transform:translateY(0)}
}
.result-primary{font-size:1.75rem;font-weight:700;color:var(--primary);margin:.25rem 0}
.result-primary.success{color:var(--success)}
.result-primary.danger{color:var(--danger)}
.result-label{font-size:.8125rem;color:var(--text-secondary)}
.result-details{display:flex;flex-wrap:wrap;gap:.75rem;margin-top:.75rem}
.result-detail{
  background:rgba(255,255,255,.7);border-radius:var(--radius);padding:.5rem .75rem;
  font-size:.8125rem;
}
.result-detail .detail-label{color:var(--text-muted);font-size:.75rem}
.result-detail .detail-value{font-weight:600;font-family:var(--mono)}

/* ===== Steps ===== */
.steps-toggle{
  font-size:.8125rem;color:var(--primary);cursor:pointer;
  background:none;border:none;font-family:var(--font);font-weight:500;
  margin-top:.75rem;
}
.steps-body{display:none;margin-top:.75rem;padding:.75rem;background:rgba(255,255,255,.7);border-radius:var(--radius);font-size:.8125rem;line-height:1.6}
.steps-body.open{display:block}
.steps-body .formula{font-family:var(--mono);background:var(--surface);padding:.35rem .6rem;border-radius:4px;display:inline-block;margin:.25rem 0}

/* ===== Warnings ===== */
.warnings{margin-top:.75rem}
.warning-msg{
  display:flex;align-items:flex-start;gap:.5rem;
  padding:.5rem .75rem;border-radius:var(--radius);
  font-size:.8125rem;margin-bottom:.35rem;
}
.warning-msg.warn{background:var(--warning-light);color:var(--warning)}
.warning-msg.error{background:var(--danger-light);color:var(--danger)}
.warning-msg.info{background:var(--primary-light);color:var(--primary)}

/* ===== Cash Flow Table ===== */
.cf-table{width:100%;border-collapse:collapse;font-size:.875rem;margin-bottom:.75rem}
.cf-table th{text-align:left;font-size:.75rem;font-weight:600;color:var(--text-muted);text-transform:uppercase;letter-spacing:.03em;padding:.35rem .5rem;border-bottom:1px solid var(--border)}
.cf-table td{padding:.35rem .5rem;border-bottom:1px solid var(--border)}
.cf-table input{width:100%;padding:.4rem .5rem;border:1px solid var(--border);border-radius:4px;font-size:.875rem;font-family:var(--mono)}
.cf-table input:focus{outline:none;border-color:var(--primary)}
.cf-table .remove-btn{
  background:none;border:none;color:var(--text-muted);cursor:pointer;
  font-size:1rem;padding:.25rem;border-radius:4px;
}
.cf-table .remove-btn:hover{color:var(--danger);background:var(--danger-light)}

/* ===== Notes ===== */
.notes-card{background:var(--primary-light);border-color:transparent}
.notes-card p{font-size:.8125rem;color:var(--text-secondary);line-height:1.6}

/* ===== Footer ===== */
.site-footer{
  text-align:center;padding:2rem 1rem;font-size:.75rem;color:var(--text-muted);
  border-top:1px solid var(--border);margin-top:2rem;
}
.site-footer a{color:var(--text-muted)}

/* ===== Copy Feedback ===== */
.copy-feedback{
  position:fixed;bottom:1.5rem;right:1.5rem;
  background:var(--text);color:#fff;padding:.6rem 1rem;
  border-radius:var(--radius);font-size:.8125rem;font-weight:500;
  opacity:0;transform:translateY(8px);transition:all .2s;pointer-events:none;z-index:200;
}
.copy-feedback.show{opacity:1;transform:translateY(0)}

/* ===== Responsive ===== */
@media(max-width:640px){
  .site-header{padding:.6rem 1rem}
  .container{padding:1rem}
  .tool-topbar h1{font-size:1.1rem}
  .result-primary{font-size:1.4rem}
  .input-grid{grid-template-columns:1fr}
}