/* ============================================
   Erv's Notebook — base design tokens
   ============================================ */

:root,
[data-theme='light'] {
  /* Surfaces — warm paper */
  --color-bg: #f7f3ea;
  --color-surface: #fbf8f1;
  --color-surface-2: #fdfcf8;
  --color-surface-offset: #f0eadb;
  --color-divider: #e1d8c3;
  --color-border: #d6cbae;

  /* Text — warm ink */
  --color-text: #2b2620;
  --color-text-muted: #6f6656;
  --color-text-faint: #a89e8a;
  --color-text-inverse: #f7f3ea;

  /* Primary accent — muted teal (links, UI) */
  --color-primary: #14646a;
  --color-primary-hover: #0d4a4f;
  --color-primary-highlight: #d7e3e2;

  /* Tag accents */
  --color-biblical: #93650f;
  --color-biblical-highlight: #ecdfc0;
  --color-technical: #14646a;
  --color-technical-highlight: #d7e3e2;

  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-full: 9999px;

  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  --shadow-sm: 0 1px 2px oklch(0.2 0.03 80 / 0.06);
  --shadow-md: 0 4px 14px oklch(0.2 0.03 80 / 0.1);

  --content-narrow: 640px;
  --content-default: 720px;

  --font-display: 'Boska', 'Iowan Old Style', serif;
  --font-body: 'Source Serif 4', 'Charter', serif;

  --text-xs: clamp(0.75rem, 0.72rem + 0.15vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.83rem + 0.2vw, 0.9375rem);
  --text-base: clamp(1.0625rem, 1rem + 0.25vw, 1.1875rem);
  --text-lg: clamp(1.25rem, 1.1rem + 0.6vw, 1.5rem);
  --text-xl: clamp(1.75rem, 1.4rem + 1.4vw, 2.5rem);
  --text-2xl: clamp(2.25rem, 1.6rem + 2.5vw, 3.25rem);

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
}

[data-theme='dark'] {
  --color-bg: #1b1814;
  --color-surface: #221e18;
  --color-surface-2: #262219;
  --color-surface-offset: #2a251c;
  --color-divider: #3a3327;
  --color-border: #453d2d;

  --color-text: #ece5d4;
  --color-text-muted: #a89c85;
  --color-text-faint: #756a56;
  --color-text-inverse: #1b1814;

  --color-primary: #62b0b6;
  --color-primary-hover: #85c4c9;
  --color-primary-highlight: #2c3a3a;

  --color-biblical: #d9ab52;
  --color-biblical-highlight: #3a3020;
  --color-technical: #62b0b6;
  --color-technical-highlight: #223434;

  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.3);
  --shadow-md: 0 4px 14px oklch(0 0 0 / 0.35);
}

/* ============================================
   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;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  hanging-punctuation: first last;
}

body {
  min-height: 100dvh;
  line-height: 1.65;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-interactive), color var(--transition-interactive);
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-interactive);
}
a:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}

h1, h2, h3 {
  font-family: var(--font-display);
  text-wrap: balance;
  line-height: 1.15;
  color: var(--color-text);
}

p, li {
  text-wrap: pretty;
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

button {
  cursor: pointer;
  background: none;
  border: none;
  font: inherit;
  color: inherit;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  white-space: nowrap;
  border: 0;
}

/* ============================================
   Layout
   ============================================ */
.wrap {
  max-width: var(--content-default);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.site-header {
  border-bottom: 1px solid var(--color-divider);
  padding-block: var(--space-8) var(--space-6);
}

.site-header__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.site-title {
  font-size: var(--text-xl);
  font-weight: 500;
  letter-spacing: -0.01em;
}
.site-title a {
  color: var(--color-text);
}
.site-title a:hover {
  color: var(--color-text);
  text-decoration: none;
}

.site-tagline {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  margin-top: var(--space-1);
  font-style: italic;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
}
.icon-btn:hover {
  background: var(--color-surface-offset);
  color: var(--color-text);
}

.rss-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}
.rss-link:hover {
  color: var(--color-primary);
  text-decoration: none;
}

/* Tag filter nav */
.tag-nav {
  display: flex;
  gap: var(--space-2);
  margin-top: var(--space-6);
  flex-wrap: wrap;
}

.tag-btn {
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  background: var(--color-surface);
}
.tag-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-text);
}
.tag-btn[aria-pressed="true"] {
  background: var(--color-text);
  color: var(--color-text-inverse);
  border-color: var(--color-text);
}

main {
  padding-block: var(--space-12) var(--space-24);
}

/* Post list */
.post-list {
  display: flex;
  flex-direction: column;
}

.post-card {
  padding-block: var(--space-8);
  border-bottom: 1px solid var(--color-divider);
}
.post-card:first-child {
  padding-top: 0;
}

.post-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-2);
  font-size: var(--text-xs);
}

.tag-badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}
.tag-badge--biblical {
  background: var(--color-biblical-highlight);
  color: var(--color-biblical);
}
.tag-badge--technical {
  background: var(--color-technical-highlight);
  color: var(--color-technical);
}

.post-date {
  color: var(--color-text-faint);
}

.post-card__title {
  font-size: var(--text-lg);
  margin-bottom: var(--space-3);
}
.post-card__title a {
  color: var(--color-text);
}
.post-card__title a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.post-card__excerpt {
  color: var(--color-text-muted);
  max-width: 65ch;
}

.empty-state {
  color: var(--color-text-muted);
  padding-block: var(--space-16);
  text-align: center;
}

/* Single post page */
.post-header {
  padding-block: var(--space-10) var(--space-8);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}
.back-link:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.post-title {
  font-size: var(--text-2xl);
  margin-block: var(--space-3) var(--space-4);
}

.post-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.post-body {
  max-width: 68ch;
}
.post-body p {
  margin-bottom: var(--space-5);
  max-width: 68ch;
}
.post-body p:first-of-type {
  font-size: var(--text-lg);
  color: var(--color-text);
}

.post-footer {
  margin-top: var(--space-12);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-divider);
}

.site-footer {
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-8);
  color: var(--color-text-faint);
  font-size: var(--text-sm);
  text-align: center;
}
.site-footer a {
  color: var(--color-text-muted);
}

@media (max-width: 560px) {
  .site-header__row {
    flex-direction: column;
    align-items: flex-start;
  }
}