/* ============================================================
   sentences.css — Simply Sentences shared stylesheet
   All pages in the Simply Sentences series link to this file.
   ============================================================ */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Nunito:ital,wght@0,400;0,500;0,600;0,700;0,800;0,900;1,400;1,500&display=swap');

/* --- CSS Variables --- */
:root {
  /* Brand palette */
  --color-bg:           #F7F4EF;   /* warm off-white page */
  --color-surface:      #FFFFFF;   /* card / panel surface */
  --color-surface-alt:  #F0EDE8;   /* slightly darker surface for alternating */
  --color-border:       #DDD8D0;   /* subtle border */
  --color-ink:          #1A1814;   /* near-black body text */
  --color-ink-mid:      #4A4540;   /* secondary text */
  --color-ink-light:    #8A8480;   /* captions, labels */

  /* Brand accent — deep teal-ink */
  --color-accent:       #1E4D5C;   /* nav, h1 accent, strong links */
  --color-accent-mid:   #2E7A8A;   /* hover states */
  --color-accent-light: #C8E4EB;   /* tinted backgrounds */

  /* Heading colors */
  --color-h1:           #1A1814;
  --color-h2:           #1E4D5C;
  --color-h3:           #2E7A8A;
  --color-h4:           #4A4540;

  /* Sentence annotation colors — muted, magazine-quality */
  --hl-subject:         #C8D8F0;   /* slate blue   — subject */
  --hl-verb:            #FFE4A0;   /* amber        — verb / main verb */
  --hl-direct-obj:      #C8E8D0;   /* sage green   — direct object */
  --hl-indirect-obj:    #F0D0D8;   /* dusty rose   — indirect object */
  --hl-prep:            #DDD0F0;   /* soft lavender — prepositional phrase */
  --hl-verbal:          #FFD8B8;   /* warm peach   — verbal phrase */
  --hl-conjunction:     #C0E0E8;   /* steel teal   — conjunction */
  --hl-note:            #FFFACC;   /* pale yellow  — general highlight / note */

  /* Typography */
  --font-main:          'Nunito', sans-serif;
  --font-mono:          'Courier New', Courier, monospace;

  /* Spacing scale */
  --space-xs:   0.25rem;
  --space-sm:   0.5rem;
  --space-md:   1rem;
  --space-lg:   1.75rem;
  --space-xl:   2.5rem;
  --space-2xl:  4rem;

  /* Layout */
  --max-width:      720px;
  --border-radius:  6px;
}

/* ============================================================
   RESET & BASE
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 17px;
}

body {
  font-family:      var(--font-main);
  font-weight:      400;
  line-height:      1.75;
  color:            var(--color-ink);
  background-color: var(--color-bg);
  /* padding-top is set dynamically by sentences.js to match
     the actual rendered nav height at any screen width */
}

/* ============================================================
   STICKY NAV
   Fully wrapping — no hamburger. Brand sits on the first row,
   links wrap naturally to additional rows on smaller screens.
   JS (sentences.js) sets body padding-top to match actual
   nav height after layout, so content is never hidden behind it.
   ============================================================ */
.site-nav {
  position:        fixed;
  top:             0;
  left:            0;
  right:           0;
  background:      var(--color-accent);
  z-index:         1000;
  display:         flex;
  flex-wrap:       wrap;
  align-items:     center;
  padding:         0.4rem var(--space-lg);
  gap:             0.2rem 0;
  box-shadow:      0 2px 8px rgba(0,0,0,0.18);
}

.nav-brand {
  font-size:       1rem;
  font-weight:     800;
  color:           #FFFFFF;
  letter-spacing:  0.03em;
  text-decoration: none;
  white-space:     nowrap;
  padding:         0.35rem 0;
  margin-right:    var(--space-lg);
  flex-shrink:     0;
  line-height:     1;
}

.nav-brand span {
  font-weight: 400;
  opacity:     0.65;
  font-size:   0.85em;
}

.nav-links {
  display:     flex;
  flex-wrap:   wrap;          /* links wrap to next row when space is tight */
  align-items: center;
  gap:         0.15rem;
  list-style:  none;
}

.nav-links a {
  display:         block;
  font-size:       0.76rem;
  font-weight:     700;
  color:           rgba(255,255,255,0.78);
  text-decoration: none;
  padding:         0.3rem 0.55rem;
  border-radius:   4px;
  transition:      background 0.18s, color 0.18s;
  letter-spacing:  0.02em;
  white-space:     nowrap;
  line-height:     1.3;
}

.nav-links a:hover,
.nav-links a.active {
  background: rgba(255,255,255,0.18);
  color:      #FFFFFF;
}

/* ============================================================
   PAGE LAYOUT
   ============================================================ */
.page-wrapper {
  max-width:  var(--max-width);
  margin:     0 auto;
  padding:    var(--space-xl) var(--space-lg) var(--space-2xl);
}

/* ============================================================
   PAGE HEADER (hero band at top of each lesson page)
   ============================================================ */
.page-header {
  padding:        var(--space-xl) 0 var(--space-lg);
  border-bottom:  3px solid var(--color-accent);
  margin-bottom:  var(--space-xl);
}

.page-header .page-label {
  font-size:      0.72rem;
  font-weight:    700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color:          var(--color-accent-mid);
  margin-bottom:  var(--space-xs);
}

.page-header h1 {
  font-size:      2.2rem;
  font-weight:    900;
  color:          var(--color-h1);
  line-height:    1.15;
  margin-bottom:  var(--space-sm);
}

.page-header .page-subtitle {
  font-size:      1rem;
  font-weight:    500;
  color:          var(--color-ink-mid);
  max-width:      520px;
}

/* ============================================================
   TYPOGRAPHY — HEADINGS
   ============================================================ */
h1, h2, h3, h4, h5, h6 {
  font-family:    var(--font-main);
  line-height:    1.2;
  color:          var(--color-ink);
}

/* Section heading — large, accent-colored, with bottom rule */
h2 {
  font-size:      1.55rem;
  font-weight:    800;
  color:          var(--color-h2);
  margin-top:     var(--space-xl);
  margin-bottom:  var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom:  2px solid var(--color-accent-light);
}

/* Sub-section heading — left accent bar */
h3 {
  font-size:      1.15rem;
  font-weight:    800;
  color:          var(--color-h3);
  margin-top:     var(--space-lg);
  margin-bottom:  var(--space-sm);
  padding-left:   var(--space-md);
  border-left:    3px solid var(--color-accent-mid);
}

/* Tertiary heading */
h4 {
  font-size:      0.95rem;
  font-weight:    700;
  color:          var(--color-h4);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  margin-top:     var(--space-lg);
  margin-bottom:  var(--space-xs);
}

/* ============================================================
   BODY CONTENT
   ============================================================ */
p {
  margin-bottom: var(--space-md);
  color:         var(--color-ink);
}

ul, ol {
  margin-left:   var(--space-lg);
  margin-bottom: var(--space-md);
}

li {
  margin-bottom: var(--space-xs);
  line-height:   1.7;
}

strong {
  font-weight: 700;
}

em {
  font-style: italic;
}

a {
  color:           var(--color-accent-mid);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset:     2px;
  transition:      color 0.15s;
}

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

/* Intro / lead paragraph */
.lead {
  font-size:   1.08rem;
  font-weight: 500;
  color:       var(--color-ink-mid);
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

/* Rule / note callout */
.note {
  background:    var(--color-surface-alt);
  border-left:   3px solid var(--color-accent-light);
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  padding:       var(--space-sm) var(--space-md);
  margin:        var(--space-md) 0;
  font-size:     0.88rem;
  color:         var(--color-ink-mid);
}

.note strong {
  color: var(--color-accent);
}

/* ============================================================
   EXAMPLE SENTENCE DISPLAY
   ============================================================ */

/* Plain sentence before annotation */
.sentence-plain {
  font-size:     1.05rem;
  font-weight:   600;
  color:         var(--color-ink-mid);
  margin-bottom: var(--space-xs);
  padding-left:  var(--space-md);
}

/* Annotated / color-coded sentence */
.sentence {
  font-size:     1.05rem;
  font-weight:   500;
  line-height:   1.9;
  padding:       var(--space-sm) var(--space-md);
  background:    var(--color-surface);
  border:        1px solid var(--color-border);
  border-radius: var(--border-radius);
  margin-bottom: var(--space-sm);
}

/* A group of related sentences */
.sentence-group {
  margin:        var(--space-md) 0 var(--space-lg);
  display:       flex;
  flex-direction: column;
  gap:           var(--space-xs);
}

/* Sentence with a label (e.g. "Add a prepositional phrase:") */
.sentence-block {
  margin: var(--space-md) 0 var(--space-lg);
}

.sentence-block .sentence-label {
  font-size:      0.78rem;
  font-weight:    700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color:          var(--color-ink-light);
  margin-bottom:  var(--space-xs);
}

/* ============================================================
   SENTENCE ANNOTATION HIGHLIGHTS
   These span-level classes mark grammatical roles inline.
   Usage: <span class="hl-subject">Suzie</span>
   ============================================================ */
[class^="hl-"] {
  border-radius: 3px;
  padding:       0.05em 0.2em;
  font-weight:   600;
}

.hl-subject      { background: var(--hl-subject);      }
.hl-verb         { background: var(--hl-verb);          }
.hl-direct-obj   { background: var(--hl-direct-obj);    }
.hl-indirect-obj { background: var(--hl-indirect-obj);  }
.hl-prep         { background: var(--hl-prep);          }
.hl-verbal       { background: var(--hl-verbal);        }
.hl-conjunction  { background: var(--hl-conjunction);   }
.hl-note         { background: var(--hl-note);          }

/* ============================================================
   ANNOTATION LEGEND
   A compact color key — include once per page, near the top.
   ============================================================ */
.annotation-legend {
  display:       flex;
  flex-wrap:     wrap;
  gap:           var(--space-sm) var(--space-md);
  margin:        var(--space-md) 0 var(--space-lg);
  padding:       var(--space-md);
  background:    var(--color-surface);
  border:        1px solid var(--color-border);
  border-radius: var(--border-radius);
  font-size:     0.82rem;
}

.legend-item {
  display:     flex;
  align-items: center;
  gap:         var(--space-xs);
  font-weight: 600;
  color:       var(--color-ink-mid);
}

.legend-swatch {
  display:       inline-block;
  width:         1.4em;
  height:        1.1em;
  border-radius: 3px;
  flex-shrink:   0;
}

/* ============================================================
   SECTION PANEL — for grammar rules / key concept boxes
   ============================================================ */
.rule-box {
  background:    var(--color-surface);
  border:        1px solid var(--color-border);
  border-top:    3px solid var(--color-accent);
  border-radius: var(--border-radius);
  padding:       var(--space-md) var(--space-lg);
  margin:        var(--space-lg) 0;
}

.rule-box h4 {
  margin-top: 0;
  color:      var(--color-accent);
}

/* ============================================================
   INDEX PAGE — LESSON CARD GRID
   ============================================================ */
.lesson-grid {
  display:               grid;
  grid-template-columns: 1fr;
  gap:                   var(--space-md);
  margin-top:            var(--space-xl);
}

.lesson-card {
  display:         flex;
  align-items:     stretch;
  background:      var(--color-surface);
  border:          1px solid var(--color-border);
  border-radius:   var(--border-radius);
  text-decoration: none;
  color:           inherit;
  overflow:        hidden;
  transition:      box-shadow 0.2s, transform 0.2s;
}

.lesson-card:hover {
  box-shadow: 0 4px 18px rgba(30,77,92,0.13);
  transform:  translateY(-2px);
}

.card-number {
  display:         flex;
  align-items:     center;
  justify-content: center;
  min-width:       56px;
  background:      var(--color-accent);
  color:           #FFFFFF;
  font-size:       1.1rem;
  font-weight:     900;
  flex-shrink:     0;
}

.card-body {
  padding: var(--space-md) var(--space-lg);
}

.card-body h3 {
  font-size:    1rem;
  font-weight:  800;
  color:        var(--color-h2);
  margin:       0 0 var(--space-xs);
  padding:      0;
  border:       none;
}

.card-body p {
  font-size:    0.85rem;
  color:        var(--color-ink-mid);
  margin:       0;
  line-height:  1.5;
}

/* ============================================================
   PAGE NAVIGATION (prev / next links at bottom)
   ============================================================ */
.page-nav {
  display:         flex;
  justify-content: space-between;
  align-items:     center;
  margin-top:      var(--space-2xl);
  padding-top:     var(--space-lg);
  border-top:      1px solid var(--color-border);
  gap:             var(--space-md);
}

.page-nav a {
  display:         flex;
  align-items:     center;
  gap:             var(--space-sm);
  font-size:       0.88rem;
  font-weight:     700;
  color:           var(--color-accent);
  text-decoration: none;
  padding:         var(--space-sm) var(--space-md);
  border:          1px solid var(--color-accent-light);
  border-radius:   var(--border-radius);
  transition:      background 0.18s;
}

.page-nav a:hover {
  background: var(--color-accent-light);
}

.page-nav a.next {
  margin-left: auto;
}

/* ============================================================
   EXAMPLE TOGGLE  [ more … | close ]
   .example-overflow holds the hidden sentences.
   .toggle-btn is the minimal text trigger.
   ============================================================ */
.example-overflow {
  display: none;
}

.example-overflow.open {
  display: contents; /* renders children inline with siblings */
}

.toggle-btn {
  display:         inline-block;
  margin-top:      var(--space-xs);
  font-size:       0.78rem;
  font-weight:     700;
  letter-spacing:  0.06em;
  color:           var(--color-accent-mid);
  cursor:          pointer;
  background:      none;
  border:          none;
  padding:         0;
  text-decoration: none;
  transition:      color 0.15s;
  user-select:     none;
}

.toggle-btn:hover {
  color: var(--color-accent);
}

/* ============================================================
   TERMINOLOGY NOTE
   Small muted line for "in traditional grammar this is called
   X — but you don't need to remember that" asides.
   ============================================================ */
.term-note {
  font-size:     0.82rem;
  color:         var(--color-ink-light);
  font-style:    italic;
  margin-top:    calc(var(--space-xs) * -0.5);
  margin-bottom: var(--space-md);
}

/* ============================================================
   SCROLL PROGRESS BAR
   JS positions this flush below the nav after measuring it.
   ============================================================ */
#scroll-progress {
  position:   fixed;
  top:        0;     /* overridden by JS */
  left:       0;
  height:     3px;
  width:      0%;
  background: var(--color-accent-mid);
  z-index:    999;
  transition: width 0.1s linear;
}

/* ============================================================
   PREPOSITION WORD CLOUD
   Flex-wrap panel for the 73 prepositions list.
   ============================================================ */
.prep-cloud {
  display:        flex;
  flex-wrap:      wrap;
  gap:            var(--space-xs) var(--space-sm);
  padding:        var(--space-md);
  background:     var(--color-surface);
  border:         1px solid var(--color-border);
  border-radius:  var(--border-radius);
  margin:         var(--space-md) 0 var(--space-lg);
  font-size:      0.9rem;
  line-height:    1;
}

.prep-cloud span,
.prep-cloud {
  /* words are just text nodes split by whitespace */
  word-spacing: 0;
}

/* Each word in the cloud gets a subtle pill treatment */
.prep-cloud::after { content: none; }

/* We render the cloud as a single text block, styled like a tag list */
.prep-cloud {
  font-weight:    600;
  color:          var(--color-accent);
  letter-spacing: 0.01em;
}

/* ============================================================
   LINKING VERB GRID
   Two-column flex grid for descriptive (linking) verbs.
   ============================================================ */
.linking-grid {
  display:               grid;
  grid-template-columns: 1fr 1fr;
  gap:                   var(--space-sm);
  margin:                var(--space-md) 0 var(--space-lg);
}

.linking-item {
  display:       flex;
  flex-direction: column;
  gap:           2px;
  background:    var(--color-surface);
  border:        1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding:       var(--space-sm) var(--space-md);
}

.linking-verb {
  font-size:    0.78rem;
  font-weight:  800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color:        var(--color-accent);
}

.linking-example {
  font-size:  0.88rem;
  color:      var(--color-ink-mid);
  line-height: 1.4;
}

@media (max-width: 500px) {
  .linking-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================================
   RESPONSIVE — MOBILE
   No hamburger. The nav wraps naturally at any screen width.
   JS measures the real nav height after wrapping and sets
   body padding-top accordingly (see sentences.js).
   ============================================================ */
@media (max-width: 700px) {
  html {
    font-size: 16px;
  }

  .site-nav {
    padding: 0.4rem var(--space-md);
  }

  .page-wrapper {
    padding: var(--space-lg) var(--space-md) var(--space-2xl);
  }

  .page-header h1 {
    font-size: 1.7rem;
  }

  h2 { font-size: 1.3rem; }
  h3 { font-size: 1.05rem; }

  /* Annotated sentences: extra breathing room on narrow screens
     so colored spans don't feel cramped when they wrap mid-line */
  .sentence {
    font-size:   0.97rem;
    line-height: 2.1;
  }

  .card-number {
    min-width: 44px;
    font-size: 0.95rem;
  }

  .lesson-card .card-body {
    padding: var(--space-sm) var(--space-md);
  }

  .page-nav {
    flex-direction: column;
    align-items:    stretch;
  }

  .page-nav a.next {
    margin-left: 0;
  }

  .annotation-legend {
    gap: var(--space-xs) var(--space-sm);
  }
}

@media (min-width: 600px) {
  .lesson-grid {
    grid-template-columns: 1fr 1fr;
  }
}