/* ══════════════════════════════════════════════
   MixRight — Concrete & Mortar Calculator
   Design: Construction / industrial precision
   Palette: Slate darks + Amber accent
   ══════════════════════════════════════════════ */

/* ── DESIGN TOKENS ─────────────────────────── */
:root,
[data-theme='light'] {
  /* Surfaces */
  --color-bg: #f4f3f0;
  --color-surface: #faf9f7;
  --color-surface-2: #ffffff;
  --color-surface-offset: #edecea;
  --color-border: #d8d5d0;
  --color-divider: #e4e2de;

  /* Text */
  --color-text: #1e1c18;
  --color-text-muted: #706d67;
  --color-text-faint: #aaa89f;
  --color-text-inverse: #faf9f7;

  /* Primary accent — construction amber */
  --color-primary: #c47b00;
  --color-primary-hover: #a86400;
  --color-primary-active: #8a4f00;
  --color-primary-bg: #fff3db;
  --color-primary-border: #f5d394;

  /* Semantic */
  --color-success: #3a7d1e;
  --color-success-bg: #edf6e8;
  --color-info: #1a5fa8;
  --color-info-bg: #e8f0fb;
  --color-warning: #9c4d00;
  --color-warning-bg: #fff0e4;
  --color-error: #9b1c3a;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 14px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 36px rgba(0,0,0,0.10);

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;

  /* Type */
  --font-display: 'Cabinet Grotesk', 'DM Sans', system-ui, sans-serif;
  --font-body: 'DM Sans', system-ui, sans-serif;
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.8125rem, 0.75rem + 0.3vw, 0.9375rem);
  --text-base: clamp(0.9375rem, 0.875rem + 0.3vw, 1.0625rem);
  --text-lg: clamp(1.0625rem, 0.95rem + 0.6vw, 1.375rem);
  --text-xl: clamp(1.25rem, 1rem + 1vw, 1.75rem);

  --transition: 160ms cubic-bezier(0.16, 1, 0.3, 1);
  --content-max: 1200px;
}

[data-theme='dark'] {
  --color-bg: #151412;
  --color-surface: #1c1a17;
  --color-surface-2: #221f1b;
  --color-surface-offset: #1a1815;
  --color-border: #3a3730;
  --color-divider: #2e2b25;
  --color-text: #e8e5df;
  --color-text-muted: #8a877f;
  --color-text-faint: #5a5750;
  --color-text-inverse: #1c1a17;
  --color-primary: #f0a830;
  --color-primary-hover: #f8bc50;
  --color-primary-active: #fdd080;
  --color-primary-bg: #2e2410;
  --color-primary-border: #6b4800;
  --color-success: #5da83b;
  --color-success-bg: #1a2e12;
  --color-info: #5499d8;
  --color-info-bg: #162035;
  --color-warning: #e07b30;
  --color-warning-bg: #281a0a;
  --color-error: #e05070;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.25);
  --shadow-md: 0 4px 14px rgba(0,0,0,0.35);
  --shadow-lg: 0 12px 36px rgba(0,0,0,0.45);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #151412;
    --color-surface: #1c1a17;
    --color-surface-2: #221f1b;
    --color-surface-offset: #1a1815;
    --color-border: #3a3730;
    --color-divider: #2e2b25;
    --color-text: #e8e5df;
    --color-text-muted: #8a877f;
    --color-text-faint: #5a5750;
    --color-text-inverse: #1c1a17;
    --color-primary: #f0a830;
    --color-primary-hover: #f8bc50;
    --color-primary-active: #fdd080;
    --color-primary-bg: #2e2410;
    --color-primary-border: #6b4800;
    --color-success: #5da83b;
    --color-success-bg: #1a2e12;
    --color-info: #5499d8;
    --color-info-bg: #162035;
    --color-warning: #e07b30;
    --color-warning-bg: #281a0a;
    --color-error: #e05070;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.25);
    --shadow-md: 0 4px 14px rgba(0,0,0,0.35);
    --shadow-lg: 0 12px 36px rgba(0,0,0,0.45);
  }
}

/* ── RESET & BASE ──────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
  overflow-x: hidden;
}

body {
  min-height: 100dvh;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.55;
  overflow-x: hidden;
  width: 100%;
}

img, svg { display: block; max-width: 100%; }
button { cursor: pointer; background: none; border: none; font: inherit; color: inherit; }
input, select, textarea { font: inherit; color: inherit; }
::selection { background: color-mix(in oklab, var(--color-primary) 25%, transparent); }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; border-radius: var(--radius-sm); }

/* ── HEADER ────────────────────────────────── */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}
.header-inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.logo-group { display: flex; align-items: center; gap: 0.6rem; }
.logo-icon { width: 32px; height: 32px; color: var(--color-primary); flex-shrink: 0; }
.logo-text {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: -0.02em;
  color: var(--color-text);
}
.header-actions { display: flex; align-items: center; gap: 0.75rem; }
.badge-uk {
  font-size: var(--text-xs);
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-full, 9999px);
  background: var(--color-primary-bg);
  color: var(--color-primary);
  border: 1px solid var(--color-primary-border);
  letter-spacing: 0.05em;
}
.theme-btn {
  width: 36px; height: 36px;
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  background: var(--color-surface-offset);
  transition: all var(--transition);
}
.theme-btn:hover { color: var(--color-text); border-color: var(--color-primary); }

/* ── MAIN LAYOUT ───────────────────────────── */
.app-main {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 1.5rem;
  display: grid;
  grid-template-columns: minmax(0, 520px) 1fr;
  grid-template-rows: auto;
  gap: 1.5rem;
  align-items: start;
  box-sizing: border-box;
  width: 100%;
}
@media (max-width: 900px) {
  .app-main { grid-template-columns: minmax(0, 1fr); padding: 1rem; gap: 1rem; }
}
@media (max-width: 480px) {
  .app-main { padding: 0.75rem; gap: 0.75rem; }
  .card { padding: 1rem; }
  .header-inner { padding: 0.6rem 1rem; }
}

.input-panel {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  grid-column: 1;
  grid-row: 1;
}
.results-panel {
  grid-column: 2;
  grid-row: 1 / 3;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.empty-state {
  grid-column: 2;
  grid-row: 1 / 3;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  min-height: 360px;
  padding: 2rem;
  gap: 1rem;
  color: var(--color-text-faint);
}
@media (max-width: 900px) {
  .results-panel, .empty-state { grid-column: 1; grid-row: auto; }
}

/* ── CARDS ─────────────────────────────────── */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
}
.card-header {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}
.card-label {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-text-inverse);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.8rem;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
  margin-top: 2px;
}
.card-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-lg);
  color: var(--color-text);
  line-height: 1.2;
}
.card-subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: 0.2rem;
  max-width: 100%;
}

/* ── FORM ELEMENTS ─────────────────────────── */
.form-group { display: flex; flex-direction: column; gap: 0.35rem; }
.form-group.tight { gap: 0.25rem; }
.form-label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.form-input {
  height: 40px;
  padding: 0 0.75rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-2);
  color: var(--color-text);
  font-size: var(--text-sm);
  transition: border-color var(--transition), box-shadow var(--transition);
  width: 100%;
}
.form-input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 3px color-mix(in oklab, var(--color-primary) 20%, transparent); }
.form-input.narrow { max-width: 140px; }
.form-select {
  height: 40px;
  padding: 0 0.75rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-2);
  color: var(--color-text);
  font-size: var(--text-sm);
  cursor: pointer;
  width: 100%;
  transition: border-color var(--transition), box-shadow var(--transition);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23888' stroke-width='1.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2.25rem;
}
.form-select:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 3px color-mix(in oklab, var(--color-primary) 20%, transparent); }
.form-hint {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  line-height: 1.5;
  padding: 0.5rem 0.75rem;
  background: var(--color-surface-offset);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-border);
}
.static-pill {
  height: 40px;
  display: flex;
  align-items: center;
  padding: 0 0.75rem;
  background: var(--color-surface-offset);
  border: 1.5px solid var(--color-divider);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: 500;
}

/* Grid helpers */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0.75rem; }
@media (max-width: 600px) {
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .grid-2 { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 400px) {
  .grid-3 { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
}

/* ── SECTION ROWS ──────────────────────────── */
#sections-container { display: flex; flex-direction: column; gap: 0.75rem; margin-bottom: 0.75rem; }

.section-row {
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface-2);
  overflow: hidden;
  transition: border-color var(--transition);
}
.section-row:focus-within { border-color: var(--color-primary); }

.section-top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 0.75rem;
  background: var(--color-surface-offset);
  border-bottom: 1px solid var(--color-divider);
  gap: 0.5rem;
}
.section-name-group { display: flex; align-items: center; gap: 0.5rem; flex: 1; min-width: 0; }
.section-num {
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-primary);
  font-family: var(--font-display);
  white-space: nowrap;
}
.section-name-input {
  flex: 1;
  min-width: 0;
  height: 30px;
  border: none;
  background: transparent;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text);
  padding: 0 0.25rem;
}
.section-name-input:focus { outline: none; }
.section-name-input::placeholder { color: var(--color-text-faint); }
.btn-remove-section {
  width: 28px; height: 28px;
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-text-faint);
  flex-shrink: 0;
  transition: all var(--transition);
}
.btn-remove-section:hover { color: var(--color-error); background: color-mix(in oklab, var(--color-error) 10%, transparent); }

.section-body { padding: 0.875rem; display: flex; flex-direction: column; gap: 0.75rem; }

/* Shape tabs */
.shape-tabs {
  display: flex;
  gap: 0.4rem;
  background: var(--color-surface-offset);
  padding: 0.25rem;
  border-radius: var(--radius-md);
  width: fit-content;
}
.shape-tab {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.3rem 0.75rem;
  border-radius: calc(var(--radius-md) - 2px);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  transition: all var(--transition);
}
.shape-tab.active {
  background: var(--color-surface-2);
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
}
.shape-tab:hover:not(.active) { color: var(--color-text); }

/* Volume preview */
.section-volume-preview {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  padding: 0.35rem 0.6rem;
  background: var(--color-surface-offset);
  border-radius: var(--radius-sm);
  width: fit-content;
}
.vol-label { font-weight: 500; }
.vol-value { color: var(--color-primary); font-weight: 600; font-family: var(--font-display); }

/* ── WASTAGE SLIDER ────────────────────────── */
.wastage-row {
  margin-top: 0.75rem;
  padding-top: 0.875rem;
  border-top: 1px solid var(--color-divider);
}
.wastage-value-display {
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--color-primary);
  background: var(--color-primary-bg);
  border: 1px solid var(--color-primary-border);
  padding: 0.1rem 0.5rem;
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
}
.slider-wrap { margin-top: 0.6rem; }
.slider {
  width: 100%;
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  border-radius: 9999px;
  background: linear-gradient(to right, var(--color-primary) 0%, var(--color-primary) var(--pct, 33.3%), var(--color-border) var(--pct, 33.3%), var(--color-border) 100%);
  outline: none;
  cursor: pointer;
}
.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 2px solid var(--color-surface-2);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: transform var(--transition);
}
.slider::-webkit-slider-thumb:hover { transform: scale(1.15); }
.slider::-moz-range-thumb {
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 2px solid var(--color-surface-2);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
}
.slider-ticks {
  display: flex;
  justify-content: space-between;
  font-size: 0.65rem;
  color: var(--color-text-faint);
  margin-top: 0.35rem;
  padding: 0 9px;
  overflow: hidden;
}

/* ── MIX INFO ──────────────────────────────── */
.mix-info {
  margin-top: 0.6rem;
  padding: 0.6rem 0.875rem;
  background: var(--color-primary-bg);
  border: 1px solid var(--color-primary-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-primary);
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  min-height: 38px;
}
.mix-info:empty { display: none; }
.custom-mix-fields { margin-top: 0.75rem; display: flex; flex-direction: column; gap: 0.75rem; }

.radio-group { display: flex; gap: 1.25rem; flex-wrap: wrap; }
.radio-label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  cursor: pointer;
}
.radio-label input { accent-color: var(--color-primary); cursor: pointer; }

/* ── ADD SECTION BUTTON ────────────────────── */
.btn-add {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border: 1.5px dashed var(--color-primary-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-primary);
  background: var(--color-primary-bg);
  width: 100%;
  justify-content: center;
  transition: all var(--transition);
}
.btn-add:hover { border-style: solid; box-shadow: var(--shadow-sm); }

/* ── ADDITIVE ROWS ─────────────────────────── */
.additive-row {
  padding: 0.875rem 0;
  border-bottom: 1px solid var(--color-divider);
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}
.additive-row:last-child { border-bottom: none; padding-bottom: 0; }

.toggle-label {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  cursor: pointer;
  user-select: none;
}
.toggle-input { display: none; }
.toggle-track {
  width: 40px; height: 22px;
  border-radius: 9999px;
  background: var(--color-border);
  position: relative;
  transition: background var(--transition);
  flex-shrink: 0;
}
.toggle-thumb {
  position: absolute;
  top: 3px; left: 3px;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--color-surface-2);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition);
}
.toggle-input:checked + .toggle-track { background: var(--color-primary); }
.toggle-input:checked + .toggle-track .toggle-thumb { transform: translateX(18px); }
.toggle-text { font-size: var(--text-sm); font-weight: 500; color: var(--color-text); }
.additive-detail { padding-left: calc(40px + 0.75rem); }

/* ── CALCULATE BUTTON ──────────────────────── */
.btn-calculate {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  width: 100%;
  padding: 0.875rem 1.5rem;
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: var(--radius-lg);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  letter-spacing: -0.01em;
  box-shadow: var(--shadow-md);
  transition: all var(--transition);
}
.btn-calculate:hover { background: var(--color-primary-hover); transform: translateY(-1px); box-shadow: var(--shadow-lg); }
.btn-calculate:active { background: var(--color-primary-active); transform: translateY(0); }

/* ── RESULTS PANEL ─────────────────────────── */
.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.results-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--text-xl);
  color: var(--color-text);
  letter-spacing: -0.02em;
}
.results-actions { display: flex; gap: 0.5rem; }
.btn-action {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.875rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  background: var(--color-surface);
  transition: all var(--transition);
}
.btn-action:hover { color: var(--color-text); border-color: var(--color-primary); background: var(--color-primary-bg); }
.btn-action.copied { color: var(--color-success); border-color: var(--color-success); background: var(--color-success-bg); }

/* Volume summary bar */
.volume-bar {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 0.875rem 1.25rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
}
.vol-stat { display: flex; flex-direction: column; gap: 0.15rem; }
.vol-stat-label { font-size: var(--text-xs); color: var(--color-text-faint); font-weight: 500; text-transform: uppercase; letter-spacing: 0.08em; }
.vol-stat-value {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-lg);
  color: var(--color-primary);
  line-height: 1;
}
.vol-stat-sub { font-size: var(--text-xs); color: var(--color-text-muted); }

/* Result cards */
.result-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.result-card-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.875rem 1.25rem;
  background: var(--color-surface-offset);
  border-bottom: 1px solid var(--color-divider);
  color: var(--color-text-muted);
}
.result-card-header h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-text);
}

/* Material row */
.material-block {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--color-divider);
}
.material-block:last-child { border-bottom: none; }

.mat-name {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}
.mat-name-text {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-text);
}
.mat-weight-badge {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-primary);
  background: var(--color-primary-bg);
  border: 1px solid var(--color-primary-border);
  padding: 0.1rem 0.6rem;
  border-radius: var(--radius-sm);
}
.mat-dot {
  width: 10px; height: 10px; border-radius: 50%; flex-shrink: 0;
}

.strategy-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 0.5rem;
}
@media (max-width: 1100px) { .strategy-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 900px) { .strategy-grid { grid-template-columns: 1fr 1fr 1fr; } }
@media (max-width: 600px) { .strategy-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 400px) { .strategy-grid { grid-template-columns: 1fr; } }

.strategy-card {
  padding: 0.625rem 0.75rem;
  background: var(--color-surface-2);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
}
.strategy-label {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  margin-bottom: 0.3rem;
}
.strategy-value {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-text);
  line-height: 1.2;
}
.strategy-detail {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: 0.15rem;
}
.strategy-card.highlight { background: var(--color-primary-bg); border-color: var(--color-primary-border); }
.strategy-card.highlight .strategy-label { color: var(--color-primary); }
.strategy-card.highlight .strategy-value { color: var(--color-primary); }
.strategy-card.highlight .strategy-detail { color: color-mix(in oklab, var(--color-primary) 70%, transparent); }

/* ── ADDITIVES CARD ────────────────────────── */
.additive-line {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.875rem 1.25rem;
  border-bottom: 1px solid var(--color-divider);
  min-width: 0;
}
.additive-line > * { min-width: 0; }
.additive-line:last-child { border-bottom: none; }
.additive-line-name { font-weight: 500; font-size: var(--text-sm); }
.additive-line-detail { font-size: var(--text-xs); color: var(--color-text-muted); margin-top: 0.2rem; }
.additive-line-qty {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-primary);
  text-align: right;
  white-space: nowrap;
}
.additive-line-retail { font-size: var(--text-xs); color: var(--color-text-muted); text-align: right; }

/* ── BATCHING GUIDE ────────────────────────── */
.batch-recipe {
  padding: 1.25rem;
}
.batch-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  margin-bottom: 0.875rem;
}
.batch-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--color-divider);
}
.batch-row:last-child { border-bottom: none; }
.batch-icon {
  width: 32px; height: 32px;
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.batch-icon.cement { background: var(--color-primary-bg); color: var(--color-primary); }
.batch-icon.agg { background: var(--color-success-bg); color: var(--color-success); }
.batch-icon.water { background: var(--color-info-bg); color: var(--color-info); }
.batch-row-label { font-size: var(--text-sm); font-weight: 500; color: var(--color-text-muted); flex: 1; }
.batch-row-value {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-text);
  text-align: right;
  word-break: break-word;
  min-width: 0;
}
.batch-note {
  margin-top: 0.875rem;
  padding: 0.6rem 0.875rem;
  background: var(--color-warning-bg);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-warning);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  line-height: 1.5;
}
.batch-note strong { color: var(--color-warning); }

/* ── EMPTY STATE ───────────────────────────── */
.empty-title { font-size: var(--text-sm); font-weight: 500; color: var(--color-text-muted); max-width: 36ch; }
.empty-title strong { color: var(--color-text); }
.empty-sub { font-size: var(--text-xs); color: var(--color-text-faint); max-width: 40ch; }

/* ── VALIDATION FEEDBACK ───────────────────── */
.error-msg {
  font-size: var(--text-xs);
  color: var(--color-error);
  padding: 0.6rem 0.875rem;
  background: color-mix(in oklab, var(--color-error) 8%, transparent);
  border: 1px solid color-mix(in oklab, var(--color-error) 25%, transparent);
  border-radius: var(--radius-md);
  margin-bottom: 0.75rem;
}

/* Cement buy row */
.cement-buy-row {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.cement-buy-row .cement-note { flex: 1; min-width: 180px; }

/* ── CUSTOM DROPDOWN ─────────────────────────── */
.cdd-wrap {
  position: relative;
  width: 100%;
}
.cdd-trigger {
  width: 100%;
  height: 40px;
  padding: 0 0.75rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-2);
  color: var(--color-text);
  font-size: var(--text-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  text-align: left;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.cdd-trigger:hover { border-color: color-mix(in oklab, var(--color-primary) 50%, var(--color-border)); }
.cdd-trigger[aria-expanded="true"] {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px color-mix(in oklab, var(--color-primary) 20%, transparent);
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
}
.cdd-label {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: var(--text-sm);
}
.cdd-arrow {
  flex-shrink: 0;
  color: var(--color-text-faint);
  transition: transform var(--transition);
}
.cdd-trigger[aria-expanded="true"] .cdd-arrow { transform: rotate(180deg); }

.cdd-list {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--color-surface-2);
  border: 1.5px solid var(--color-primary);
  border-top: none;
  border-bottom-left-radius: var(--radius-md);
  border-bottom-right-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 9999;
  list-style: none;
  max-height: 280px;
  overflow-y: auto;
  overscroll-behavior: contain;
}
.cdd-list.open { display: block; }
.cdd-option {
  padding: 0.6rem 0.875rem;
  font-size: var(--text-sm);
  color: var(--color-text);
  cursor: pointer;
  border-bottom: 1px solid var(--color-divider);
  transition: background var(--transition), color var(--transition);
  line-height: 1.35;
}
.cdd-option:last-child { border-bottom: none; }
.cdd-option:hover { background: var(--color-primary-bg); color: var(--color-primary); }
.cdd-option:hover .cdd-sub { color: color-mix(in oklab, var(--color-primary) 70%, transparent); }
.cdd-option.selected {
  background: var(--color-primary-bg);
  color: var(--color-primary);
  font-weight: 600;
}
.cdd-option.selected .cdd-sub { color: color-mix(in oklab, var(--color-primary) 70%, transparent); }
.cdd-sub {
  display: block;
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 400;
  margin-top: 0.1rem;
}

/* ── MODE TABS ─────────────────────────────── */
.mode-tabs {
  display: flex;
  gap: 0.35rem;
  background: var(--color-surface-offset);
  padding: 0.2rem;
  border-radius: var(--radius-md);
  width: fit-content;
  margin-bottom: 0.75rem;
}
.mode-tab {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.3rem 0.7rem;
  border-radius: calc(var(--radius-md) - 2px);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  transition: all var(--transition);
  white-space: nowrap;
}
.mode-tab.active {
  background: var(--color-surface-2);
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
}
.mode-tab:hover:not(.active) { color: var(--color-text); }
.mode-panel { display: none; }
.mode-panel.active { display: block; }

/* Input with unit suffix */
.input-unit-wrap {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.input-unit-wrap .form-input { flex: 1; }
.input-unit {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  white-space: nowrap;
  flex-shrink: 0;
}
.field-hint {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: 0.35rem;
  line-height: 1.4;
}

/* ── PRINT ─────────────────────────────────── */
@media print {
  .app-header, .input-panel, .empty-state, .results-actions, .btn-calculate,
  .btn-add, .wastage-row, .header-actions, .theme-btn { display: none !important; }
  .app-main { display: block; padding: 0; max-width: 100%; }
  .results-panel { display: block !important; width: 100%; }
  .result-card { break-inside: avoid; box-shadow: none; border: 1px solid #ccc; }
  body { background: white; color: black; }
  .mat-weight-badge, .strategy-value, .vol-stat-value { color: #000 !important; }
}