/* ============================================================
   StudyHub Base Styles – Reset & Foundation
   ============================================================ */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

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

html {
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  font-size: var(--text-base);
  font-weight: var(--font-normal);
  line-height: var(--leading-normal);
  color: var(--text-primary);
  background-color: var(--bg-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  min-height: 100vh;
  min-height: 100dvh;
}

/* ── Typography ── */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-bold);
  line-height: var(--leading-tight);
  color: var(--text-primary);
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-md); }

p {
  margin-bottom: var(--space-3);
  color: var(--text-secondary);
}

a {
  color: var(--text-link);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

a:focus-visible {
  outline: 2px solid var(--primary-500);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

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

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

/* ── Forms ── */
input, button, textarea, select {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  color: inherit;
}

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

input:focus, textarea:focus, select:focus {
  outline: none;
}

/* ── Tables ── */
table {
  border-collapse: collapse;
  width: 100%;
}

/* ── Misc ── */
hr {
  border: none;
  border-top: 1px solid var(--border-light);
  margin: var(--space-6) 0;
}

::selection {
  background-color: var(--primary-200);
  color: var(--primary-900);
}

/* ── Scrollbar ── */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--gray-300);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--gray-400);
}

/* ── Focus Visible ── */
:focus-visible {
  outline: 2px solid var(--primary-500);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

/* ── Page wrapper ── */
.page {
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

.page-content {
  flex: 1;
  padding-bottom: calc(var(--bottom-nav-height) + var(--space-4));
}

/* Has header */
.page-content.has-header {
  padding-top: var(--header-height);
}

/* ── 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;
}

/* ── Visually Hidden ── */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}