:root {
  --bg: #0f172a;          /* dark slate */
  --bg-light: #f8fafc;    /* light gray */
  --text: #e2e8f0;        /* slate-200 */
  --text-dark: #0f172a;   /* slate-900 */
  --primary: #6366f1;     /* indigo-500 */
  --secondary: #22c55e;   /* green-500 */
  --card: #1e293b;        /* slate-800 */
  --border: #334155;      /* slate-700 */
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; font-size: 16px; } /* Base font size */
body.theme-dark { background: var(--bg); color: var(--text); }
body.theme-light { background: var(--bg-light); color: var(--text-dark); }

.nav {
  display: flex; align-items: center; justify-content: space-between;
  padding: 1rem 2rem; border-bottom: 1px solid var(--border);
  position: sticky; top: 0; backdrop-filter: blur(6px);
  font-size: 1rem; /* 16px for nav links */
}
.nav__brand { font-weight: 700; letter-spacing: .5px; font-size: 1.25rem; } /* 20px */
.nav__links a {
  margin: 0 .5rem; text-decoration: none; padding: .5rem .75rem; border-radius: .5rem;
  color: inherit; font-size: 1rem; /* 16px */
}
.nav__links a.active { background: rgba(99,102,241,.15); color: var(--primary); }

.hero { text-align: center; padding: 4rem 2rem; font-size: 1rem; }
.hero__title { font-size: 2.5rem; margin: 0; } /* 40px */
.hero__subtitle { margin: .5rem 0 2rem 0; opacity: .8; font-size: 1.125rem; } /* 18px */
.hero__actions { display: inline-flex; gap: .75rem; }

.grid {
  display: grid; gap: 1rem; padding: 2rem;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.card {
  background: rgba(30,41,59,.7); color: var(--text);
  border: 1px solid var(--border); border-radius: 1rem; padding: 1rem;
  font-size: 1rem; /* 16px */
}
body.theme-light .card { background: white; color: var(--text-dark); border-color: #e5e7eb; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: .6rem 1rem; border-radius: .6rem; border: 1px solid transparent;
  cursor: pointer; transition: transform .08s ease, box-shadow .2s ease;
  font-size: 1rem; /* 16px */
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 8px 24px rgba(99,102,241,.15); }
.btn:active { transform: translateY(0); }
.btn--primary { background: var(--primary); color: white; }
.btn--secondary { background: var(--secondary); color: #04210f; }
.btn--ghost { background: transparent; border-color: var(--border); }

.footer { text-align: center; padding: 2rem; opacity: .7; font-size: 0.9375rem; } /* 15px */

.animate-gradient {
  background: linear-gradient(90deg, #22c55e, #06b6d4, #6366f1);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  animation: hue 6s linear infinite;
}
@keyframes hue { 0% { filter: hue-rotate(0deg);} 100% { filter: hue-rotate(360deg);} }

.fade-in { animation: fade .6s ease both; }
@keyframes fade { from { opacity: 0; transform: translateY(6px);} to { opacity: 1; transform: none;} }

.wiggle { animation: wiggle 1.2s ease infinite; }
@keyframes wiggle {
  0%, 100% { transform: rotate(0); }
  25% { transform: rotate(1deg); }
  50% { transform: rotate(-1deg); }
  75% { transform: rotate(0.5deg); }
}

.temp { display: grid; gap: .75rem; align-items: center; }
.temp__controls { display: inline-flex; gap: .5rem; }
.temp__reading { font-size: 2.2rem; font-weight: 700; } /* 35px */
.temp__value { min-width: 3ch; display: inline-block; }
.temp__status { font-size: .9rem; opacity: .8; } /* 14px */

.spinner {
  width: 24px; height: 24px; border: 3px solid rgba(99,102,241,.25);
  border-top-color: var(--primary); border-radius: 50%;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.content { padding: 2rem; font-size: 1rem; } /* 16px */
.form { display: grid; gap: .75rem; font-size: 1rem; } /* 16px */
.form input, .form textarea {
  width: 100%; padding: .6rem .8rem; border: 1px solid var(--border);
  border-radius: .5rem; background: transparent; color: inherit; font-size: 1rem; /* 16px */
}
.form__status { margin-top: .5rem; min-height: 1.2rem; font-size: 0.875rem; } /* 14px */
.stack { display: inline-flex; gap: .5rem; font-size: 1rem; } /* 16px */