/* Conventions simples & lisibles : variables + classes */
:root{
  --bg: #f3f4f6;        /* gris très clair */
  --card: #ffffff;
  --text: #111827;      /* texte visible */
  --muted: #6b7280;
  --border: rgba(17, 24, 39, 0.12);
  --shadow: 0 10px 30px rgba(0,0,0,0.06);

  --primary: #4b5563;
  --primary-strong: #374151;

  --good: #0f766e;
  --warn: #b45309;
  --bad: #b91c1c;

  --focus: rgba(17, 24, 39, 0.25);

  --radius: 14px;
  --container-max: 980px;
}

:root[data-theme="dark"]{
  --bg: #0b1220;
  --card: #0f172a;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --border: rgba(229, 231, 235, 0.14);
  --shadow: 0 10px 30px rgba(0,0,0,0.35);

  --primary: #94a3b8;
  --primary-strong: #e5e7eb;

  --good: #2dd4bf;
  --warn: #fbbf24;
  --bad: #fb7185;

  --focus: rgba(229, 231, 235, 0.25);
}

* { box-sizing: border-box; }

html, body{
  height: 100%;
}

body{
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Arial, "Apple Color Emoji","Segoe UI Emoji";
  color: var(--text);
  background: var(--bg);
}

.topbar{
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 18px 18px;
  display: flex;
  gap: 14px;
  align-items: center;
  justify-content: space-between;
}

.topbar h1{
  margin: 0;
  font-size: 20px;
  letter-spacing: 0.2px;
}

.logo{
  width: 70px;
  height: auto;
  border-radius: 90px;
  display: grid;
  place-items: center;
  display: block;
}

.theme{
  display: flex;
  gap: 10px;
  align-items: center;
}

.theme-label{
  color: var(--muted);
  font-size: 14px;
}

select{
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 8px 10px;
  outline: none;
}

select:focus-visible{
  box-shadow: 0 0 0 4px var(--focus);
}

.container{
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 18px 32px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.card{
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px;
}

.card h2{
  margin: 0 0 14px;
  font-size: 18px;
}

.form{
  display: grid;
  gap: 12px;
}

.field label{
  display: block;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 14px;
}

.field input{
  width: 100%;
  padding: 11px 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
  outline: none;
}

.field input::placeholder{
  color: color-mix(in srgb, var(--muted), transparent 30%);
}

.field input:focus-visible{
  box-shadow: 0 0 0 4px var(--focus);
}

.actions{
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

button{
  border: 0;
  border-radius: 12px;
  padding: 11px 14px;
  background: var(--primary);
  color: #fff;
  cursor: pointer;
  font-weight: 650;
}

button:hover{
  background: var(--primary-strong);
}

button:focus-visible{
  outline: none;
  box-shadow: 0 0 0 4px var(--focus);
}

button.secondary{
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.result{
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px dashed var(--border);
}

.result-line{
  display: flex;
  gap: 12px;
  align-items: baseline;
  justify-content: space-between;
  padding: 6px 0;
}

.result-label{
  color: var(--muted);
  font-size: 14px;
}

.bmi{
  font-size: 24px;
  letter-spacing: 0.2px;
}

.category{
  font-weight: 700;
}

.note{
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.35;
}

.tips ul{
  margin: 0;
  padding-left: 18px;
  display: grid;
  gap: 8px;
}

.small{
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.35;
}