/* ═══════════════════════════════════════════════════════
   FREEscience — Base Styles
   ═══════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ── Reset ── */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  overflow-wrap: anywhere;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  font-size: var(--fs-base);
  font-weight: var(--fw-regular);
  line-height: var(--lh-normal);
  color: var(--text);
  background-color: var(--bg);
  min-height: 100vh;
}

::selection {
  background: var(--accent);
  color: var(--accent-on);
}

/* ── Typography ── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--fw-semibold);
  line-height: var(--lh-tight);
  color: var(--text);
}

h1 { font-size: var(--fs-3xl); letter-spacing: -0.8px; }
h2 { font-size: var(--fs-2xl); letter-spacing: -0.4px; }
h3 { font-size: var(--fs-md); }
h4 { font-size: var(--fs-base); }
h5 { font-size: var(--fs-sm); }
h6 { font-size: var(--fs-xs); }

p {
  line-height: var(--lh-normal);
  color: inherit;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-smooth);
}

a:hover {
  color: var(--color-accent-hover);
}

strong, b { font-weight: var(--fw-semibold); }
small { font-size: var(--fs-sm); }

/* ── Lists ── */
ul, ol {
  list-style: none;
}

/* ── Images ── */
img, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

/* ── Forms base ── */
input, textarea, select, button {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  outline: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

input:focus-visible,
textarea:focus-visible,
select:focus-visible,
button:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

/* ── Utility: Hidden ── */
[hidden] { display: none !important; }

/* ── Utility: Screen Reader Only ── */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ── Utility: Text ── */
.text-muted   { color: var(--muted); }
.text-accent  { color: var(--accent); }
.text-danger  { color: var(--color-danger); }
.text-success { color: var(--color-success); }
.text-center  { text-align: center; }
.text-right   { text-align: right; }
.text-sm      { font-size: var(--fs-sm); }
.text-xs      { font-size: var(--fs-xs); }
.font-medium  { font-weight: var(--fw-medium); }
.font-bold    { font-weight: var(--fw-semibold); }

/* ── Utility: Flex ── */
.flex         { display: flex; }
.flex-col     { flex-direction: column; }
.flex-wrap    { flex-wrap: wrap; }
.flex-1       { flex: 1; }
.items-center { align-items: center; }
.items-start  { align-items: flex-start; }
.items-end    { align-items: flex-end; }
.justify-center  { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end     { justify-content: flex-end; }
.gap-xs { gap: var(--space-xs); }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.gap-xl { gap: var(--space-xl); }

/* ── Utility: Spacing ── */
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }
.min-w-200 { min-width: 200px; }

/* ── Animations ── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}
@keyframes slideDown {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.96); }
  to   { opacity: 1; transform: scale(1); }
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0.45; }
}

.animate-fade-up    { animation: fadeUp 0.5s var(--ease-out) forwards; opacity: 0; }
.animate-fade-in    { animation: fadeIn 0.35s var(--ease-smooth) forwards; opacity: 0; }
.animate-slide-down { animation: slideDown 0.25s var(--ease-out) forwards; opacity: 0; }

.delay-1 { animation-delay: 0.08s; }
.delay-2 { animation-delay: 0.16s; }
.delay-3 { animation-delay: 0.24s; }
.delay-4 { animation-delay: 0.32s; }
.delay-5 { animation-delay: 0.4s; }

/* ── Scrollbar ── */
::-webkit-scrollbar       { width: 5px; }
::-webkit-scrollbar-track { background: var(--stone-100); }
::-webkit-scrollbar-thumb { background: var(--stone-300); border-radius: var(--radius-full); }
::-webkit-scrollbar-thumb:hover { background: var(--stone-400); }

/* ── Kicker label ── */
.kicker {
  display: block;
  font-size: var(--fs-xs);
  font-weight: var(--fw-bold);
  letter-spacing: 1.6px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--space-sm);
}