/* ============================================================
   YieldFlow Pro — Google Material Design 3 (Material You)
   Light + Dark dynamic color scheme, elevation, shape tokens.
   Keeps existing class names so every page keeps working.
   ============================================================ */

/* ---------- Color & shape tokens (Material 3 semantics) ---------- */
:root {
  --md-primary: #40587e;
  --md-on-primary: #ffffff;
  --md-primary-container: #d7e2fd;
  --md-on-primary-container: #0b1d3a;
  --md-secondary: #575e71;
  --md-on-secondary: #ffffff;
  --md-secondary-container: #dbe2f8;
  --md-on-secondary-container: #141b2c;
  --md-tertiary: #675d1c;
  --md-on-tertiary: #ffffff;
  --md-tertiary-container: #f0e197;
  --md-on-tertiary-container: #211b00;
  --md-error: #ba1a1a;
  --md-on-error: #ffffff;
  --md-error-container: #ffdad6;
  --md-on-error-container: #410002;
  --md-background: #f9f9ff;
  --md-on-background: #191c20;
  --md-surface: #f9f9ff;
  --md-on-surface: #191c20;
  --md-surface-variant: #e0e2ec;
  --md-on-surface-variant: #44474f;
  --md-outline: #74777f;
  --md-outline-variant: #c4c6d0;
  --md-surface-tint: #40587e;
  /* elevation shadows */
  --md-elevation1: 0 1px 2px rgba(0,0,0,.3), 0 1px 3px 1px rgba(0,0,0,.15);
  --md-elevation2: 0 1px 2px rgba(0,0,0,.3), 0 2px 6px 2px rgba(0,0,0,.15);
  --md-elevation3: 0 1px 3px rgba(0,0,0,.3), 0 4px 8px 3px rgba(0,0,0,.15);
  /* shape tokens */
  --md-shape-sm: 8px;
  --md-shape-md: 12px;
  --md-shape-lg: 16px;
  --md-shape-xl: 28px;
  --md-shape-pill: 999px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --md-primary: #aec6ff;
    --md-on-primary: #102f56;
    --md-primary-container: #284573;
    --md-on-primary-container: #d7e2fd;
    --md-secondary: #bfc6dc;
    --md-on-secondary: #293041;
    --md-secondary-container: #3f4759;
    --md-on-secondary-container: #dbe2f8;
    --md-tertiary: #d4c57e;
    --md-on-tertiary: #373000;
    --md-tertiary-container: #4f4706;
    --md-on-tertiary-container: #f0e197;
    --md-error: #ffb4ab;
    --md-on-error: #690005;
    --md-error-container: #93000a;
    --md-on-error-container: #ffdad6;
    --md-background: #111318;
    --md-on-background: #e2e2e9;
    --md-surface: #111318;
    --md-on-surface: #e2e2e9;
    --md-surface-variant: #44474f;
    --md-on-surface-variant: #c4c6d0;
    --md-outline: #8e9099;
    --md-outline-variant: #44474f;
  }
}

/* ---------- Backward-compat aliases (old --gold/--card/--bg etc.) ---------- */
:root {
  --gold: var(--md-primary);
  --green: var(--md-tertiary);
  --bg: var(--md-background);
  --card: var(--md-surface);
  --card2: var(--md-surface-variant);
  --txt: var(--md-on-background);
  --muted: var(--md-on-surface-variant);
  --line: var(--md-outline-variant);
}

/* ---------- Base ---------- */
* { box-sizing: border-box; margin: 0; }
html { -webkit-text-size-adjust: 100%; }
body {
  font-family: Roboto, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  background: var(--md-background);
  color: var(--md-on-background);
  line-height: 1.5;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  transition: background-color .3s ease, color .3s ease;
}
a { color: var(--md-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Layout ---------- */
.wrap { max-width: 1080px; margin: 0 auto; padding: 16px 20px 64px; }
main.tool { max-width: 980px; margin: 0 auto; padding: 16px 20px 64px; }

/* ---------- Top app bar ---------- */
.nav {
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  padding: 12px 8px;
}
.brand { font-weight: 600; color: var(--md-on-background); font-size: 1.3rem; letter-spacing: .1px; display: flex; flex-direction: column; }
.brand small { color: var(--md-on-surface-variant); font-size: .78rem; font-weight: 400; margin-top: 2px; }
.nav a { color: var(--md-on-background); font-weight: 500; }

/* ---------- Typography ---------- */
h1 { font-size: clamp(1.6rem, 3vw, 2.6rem); font-weight: 600; letter-spacing: 0; margin-bottom: .5rem; color: var(--md-on-background); }
h2 { font-weight: 600; color: var(--md-on-background); }
.sub { color: var(--md-on-surface-variant); font-size: 1.02rem; max-width: 720px; }

/* ---------- Cards (Material elevated card) ---------- */
.grid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); margin-top: 24px; }
.card {
  background: var(--md-surface);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-md);
  padding: 20px 20px 16px;
  display: flex; flex-direction: column; gap: 8px;
  box-shadow: var(--md-elevation1);
  transition: box-shadow .2s ease, transform .2s ease, border-color .2s ease;
  color: inherit;
}
.card:hover {
  box-shadow: var(--md-elevation2);
  transform: translateY(-2px);
  border-color: var(--md-primary);
  text-decoration: none;
}
.card h2 { font-size: 1.05rem; font-weight: 600; }
.card p { color: var(--md-on-surface-variant); font-size: .92rem; flex: 1; }
.card .go { align-self: flex-end; color: var(--md-primary); font-weight: 600; font-size: .9rem; margin-top: 8px; }
.badge {
  font-size: .68rem; background: var(--md-tertiary-container); color: var(--md-on-tertiary-container);
  padding: 3px 10px; border-radius: var(--md-shape-pill); font-weight: 600; vertical-align: middle; margin-left: 6px;
}

/* ---------- Panels (filled surface panels) ---------- */
.panel {
  background: color-mix(in srgb, var(--md-surface) 82%, var(--md-surface-variant));
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-md);
  padding: 20px;
  color: var(--md-on-surface);
}

/* ---------- Forms (Material outlined text fields) ---------- */
.row { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); }
label { font-size: .8rem; color: var(--md-on-surface-variant); display: block; margin-bottom: 4px; font-weight: 500; letter-spacing: .3px; }
input, select {
  background: transparent; color: var(--md-on-surface);
  border: 1px solid var(--md-outline); border-radius: 4px;
  padding: 12px 12px; font-size: 1rem; width: 100%;
  transition: border-color .2s ease, box-shadow .2s ease;
  font-family: inherit;
}
input:focus, select:focus {
  outline: none; border-color: var(--md-primary); border-width: 2px; padding: 11px;
  box-shadow: none;
}
input[type=range] { accent-color: var(--md-primary); padding: 0; border: none; }

/* ---------- Buttons (Material filled + tonal) ---------- */
button {
  background: var(--md-primary); color: var(--md-on-primary);
  border: 0; border-radius: var(--md-shape-pill);
  padding: 12px 24px; font-weight: 600; cursor: pointer; font-size: .95rem;
  font-family: inherit; letter-spacing: .3px;
  box-shadow: var(--md-elevation1);
  transition: box-shadow .2s ease, background-color .2s ease;
}
button:hover { box-shadow: var(--md-elevation2); background: color-mix(in srgb, var(--md-primary) 92%, #000); }
button:active { box-shadow: var(--md-elevation1); }
button.ghost {
  background: transparent; border: 1px solid var(--md-outline-variant); color: var(--md-on-surface);
  box-shadow: none;
}
button.ghost:hover { background: color-mix(in srgb, var(--md-primary) 8%, transparent); box-shadow: none; }

/* ---------- Results (Material surface container) ---------- */
.out {
  margin-top: 16px; padding: 18px;
  border: 1px solid var(--md-outline-variant); border-radius: var(--md-shape-md);
  background: var(--md-surface);
  box-shadow: var(--md-elevation1);
}
.out .big { font-size: 1.7rem; font-weight: 700; color: var(--md-primary); }
.out .lbl { color: var(--md-on-surface-variant); font-size: .8rem; text-transform: uppercase; letter-spacing: .4px; }

/* ---------- KPI chips ---------- */
.kpis { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }
.kpi {
  background: var(--md-surface); border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-sm); padding: 14px 16px;
  box-shadow: var(--md-elevation1);
}
.kpi .v { font-size: 1.25rem; font-weight: 700; color: var(--md-primary); }
.kpi .k { font-size: .78rem; color: var(--md-on-surface-variant); margin-top: 4px; }

/* ---------- Tables (Material data table feel) ---------- */
table { width: 100%; border-collapse: collapse; font-size: .88rem; margin-top: 12px; }
th, td { border-bottom: 1px solid var(--md-outline-variant); padding: 12px 10px; text-align: right; }
th { color: var(--md-on-surface-variant); font-size: .78rem; font-weight: 600; letter-spacing: .3px; text-transform: uppercase; }
td.num { font-variant-numeric: tabular-nums; }
tbody tr:hover { background: color-mix(in srgb, var(--md-primary) 6%, transparent); }

/* ---------- Footer ---------- */
.foot { color: var(--md-on-surface-variant); font-size: .84rem; text-align: center; margin-top: 48px; }

/* ---------- FAQ accordions (Material list container) ---------- */
details {
  border: 1px solid var(--md-outline-variant); border-radius: var(--md-shape-sm);
  padding: 14px 16px; margin-top: 12px; background: var(--md-surface);
  box-shadow: var(--md-elevation1);
}
details summary { cursor: pointer; font-weight: 600; color: var(--md-on-surface); }
details[open] summary { color: var(--md-primary); }
details p { color: var(--md-on-surface-variant); margin-top: 8px; }
.faq { margin-top: 20px; }
.faq details { background: var(--md-surface); border-radius: var(--md-shape-sm); }

/* ---------- Small utilities ---------- */
::selection { background: var(--md-primary-container); color: var(--md-on-primary-container); }