/* ==========================================================================
   நன்னூல் · Naṉṉūl — Ink-Blue & Manuscript-Slate Theme
   462 grammatical sūtras · Pavananti Muṉivar · c. 12th–13th century CE

   Visual identity: deep ink-blue, manuscript slate-grey, palm-leaf ivory,
   and the cool precision of the written rule.

   The Naṉṉūl is a grammar — not a poem or a hymn or a love anthology,
   but a systematic account of the Tamil language itself: its sounds,
   its letters, its words, its forms, its metres. It is the invisible
   architecture beneath every poem in this library.

   The palette is the palette of the scholar's study: deep ink-blue
   (the colour of the stylus marking palm-leaf), cool slate-grey
   (the manuscript page), and precise white (the incised letter).
   Where every other work in this library is warm — amber, copper, teal,
   crimson, flame — Naṉṉūl is cool: the colour of thought made exact.
   ========================================================================== */

:root {
  /* Ink-blue primaries */
  --nn-blue:        #1a2e5a;   /* deep ink blue */
  --nn-blue-mid:    #2a3e6a;   /* mid ink blue */
  --nn-blue-bright: #3a5080;   /* bright blue */
  --nn-blue-pale:   rgba(26,46,90,0.10);
  --nn-blue-pale2:  rgba(26,46,90,0.06);

  /* Manuscript slate */
  --nn-slate:       #4a5870;   /* manuscript slate */
  --nn-slate-light: #6a7890;   /* light slate */
  --nn-slate-pale:  rgba(74,88,112,0.12);

  /* Palm-leaf ivory */
  --nn-ivory:       #e8e0cc;   /* palm leaf ivory */
  --nn-ink:         #1a1a2e;   /* deep ink */

  /* Chapter / section accent colours */
  --nn-ch1: #1a2e5a;   /* Eḻuttatikāram chapters — ink blue */
  --nn-ch2: #2a3e6a;
  --nn-ch3: #3a4e7a;
  --nn-ch4: #1a3a5a;
  --nn-ch5: #2a3a5a;   /* Collatikāram chapters — deeper */
  --nn-ch6: #1a3050;
  --nn-ch7: #2a4060;
  --nn-ch8: #1e3858;
  --nn-ch9: #283668;
  --nn-ch10:#1e3260;

  /* Override site palette */
  --accent-vermillion: var(--nn-blue);
  --accent-kumkum:     var(--nn-blue-mid);
  --accent-ochre:      var(--nn-slate);
  --accent-gold:       var(--nn-blue);
}

/* ---------------------------------------------------------------------------
   Background: cool slate manuscript
   --------------------------------------------------------------------------- */
body { background: #c4c8d0; }
body::before {
  background-image:
    repeating-linear-gradient(0deg,
      transparent 0px, transparent 3px,
      rgba(26,46,90,0.025) 3px, rgba(26,46,90,0.025) 4px),
    repeating-linear-gradient(0deg,
      transparent 0px, transparent 60px,
      rgba(26,46,90,0.04) 60px, rgba(26,46,90,0.04) 61px,
      transparent 61px, transparent 140px,
      rgba(26,46,90,0.025) 140px, rgba(26,46,90,0.025) 142px),
    url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0.10 0 0 0 0 0.12 0 0 0 0 0.22 0 0 0 0.10 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* Header */
.site-header { border-bottom-color: rgba(26,46,90,0.3); }
.site-logo .mark { color: var(--nn-blue); }
.wordmark-tamil { color: var(--nn-blue); }
.site-nav a { color: var(--nn-blue-mid); }
.site-nav a:hover { color: var(--nn-blue); }
a { color: var(--nn-blue); }
a:hover { color: var(--nn-blue-mid); }

/* ---------------------------------------------------------------------------
   Index — two book cards
   --------------------------------------------------------------------------- */
.nn-books {
  max-width: 900px;
  margin: 0 auto 4rem;
  padding: 0 1.5rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(380px, 1fr));
  gap: 1.25rem;
}
@media (max-width: 480px) { .nn-books { grid-template-columns: 1fr; } }

.nn-book-card {
  display: block;
  position: relative;
  text-decoration: none;
  color: inherit;
  border-radius: 5px;
  overflow: hidden;
  padding: 2rem 2.25rem 1.75rem;
  background: var(--bg-paper);
  background-image: repeating-linear-gradient(0deg,
    rgba(26,46,90,0.018) 0px, rgba(26,46,90,0.018) 1px,
    transparent 1px, transparent 8px);
  border: 1px solid rgba(26,46,90,0.25);
  box-shadow: 0 2px 6px rgba(10,20,50,0.08), 0 6px 24px rgba(10,20,50,0.06);
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.nn-book-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 20px rgba(10,20,50,0.15), 0 12px 36px rgba(10,20,50,0.09);
  border-color: rgba(26,46,90,0.5);
}
.nn-book-card::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 5px;
}
.nn-book-card[data-book="1"]::before { background: linear-gradient(180deg,#1a2e5a,#2a3e6a); }
.nn-book-card[data-book="2"]::before { background: linear-gradient(180deg,#2a3e6a,#3a4e7a); }
.nn-book-card::after {
  content: '';
  position: absolute;
  right: 16px; top: 50%;
  transform: translateY(-50%);
  width: 13px; height: 13px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 1.5px solid rgba(26,46,90,0.35);
  box-shadow: inset 0 1px 2px rgba(0,0,0,.18);
}
.nn-book-num { font-family: var(--font-display); font-size: .68rem; letter-spacing: .28em; text-transform: uppercase; color: var(--ink-muted); margin-bottom: .5rem; }
.nn-book-tamil { font-family: var(--font-tamil); font-size: 1.75rem; font-weight: 800; color: var(--ink-primary); line-height: 1.15; margin-bottom: .15rem; }
.nn-book-eng { font-family: var(--font-display); font-style: italic; font-size: 1.05rem; color: var(--nn-blue-mid); margin-bottom: .9rem; }
.nn-book-desc { font-size: .95rem; line-height: 1.7; color: var(--ink-secondary); margin-bottom: 1.25rem; }
.nn-book-meta { display: flex; align-items: center; justify-content: space-between; padding-top: 1rem; border-top: 1px solid var(--border-subtle); }
.nn-book-count { font-size: .75rem; color: var(--ink-muted); letter-spacing: .1em; }
.nn-book-cta { font-family: var(--font-display); font-style: italic; font-size: .9rem; color: var(--nn-blue); opacity: 0; transition: opacity .2s ease; }
.nn-book-card:hover .nn-book-cta { opacity: 1; }

/* ---------------------------------------------------------------------------
   Book page — chapter cards
   --------------------------------------------------------------------------- */
.nn-book-banner {
  padding: 2rem 2.5rem 1.75rem;
  border-radius: 5px;
  color: white;
  margin-bottom: 2.5rem;
  position: relative;
  overflow: hidden;
}
.nn-book-banner[data-book="1"] { background: linear-gradient(135deg,#1a2e5a,#0e1e40); }
.nn-book-banner[data-book="2"] { background: linear-gradient(135deg,#2a3e6a,#1a2850); }
.nn-book-banner::after {
  content: '';
  position: absolute; right: 20px; top: 50%; transform: translateY(-50%);
  width: 15px; height: 15px; border-radius: 50%;
  background: rgba(0,0,0,.25); border: 1.5px solid rgba(255,255,255,.18);
}
.nn-banner-num { font-family: var(--font-display); font-size: .7rem; letter-spacing: .3em; text-transform: uppercase; opacity: .7; margin-bottom: .5rem; }
.nn-banner-tamil { font-family: var(--font-tamil); font-size: clamp(1.75rem,4vw,2.4rem); font-weight: 800; line-height: 1.1; margin-bottom: .2rem; }
.nn-banner-eng { font-family: var(--font-display); font-style: italic; font-size: 1.1rem; opacity: .85; margin-bottom: .75rem; }
.nn-banner-desc { font-size: .9rem; line-height: 1.6; opacity: .75; max-width: 680px; }

/* Chapter card grid */
.nn-chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.1rem;
  margin-bottom: 2.5rem;
}
.nn-chapter-card {
  display: block;
  background: var(--bg-paper);
  background-image: repeating-linear-gradient(0deg,
    rgba(26,46,90,0.018) 0px, rgba(26,46,90,0.018) 1px,
    transparent 1px, transparent 8px);
  border: 1px solid rgba(26,46,90,0.22);
  border-left: 4px solid var(--nn-blue);
  border-radius: 4px;
  padding: 1.1rem 1.3rem 1rem;
  text-decoration: none;
  color: inherit;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
  box-shadow: 0 1px 3px rgba(10,20,50,0.07);
}
.nn-chapter-card:hover { transform: translateY(-3px); box-shadow: 0 4px 14px rgba(10,20,50,0.13); border-color: rgba(26,46,90,0.45); }
.nn-ch-num { font-family: var(--font-display); font-size: .67rem; letter-spacing: .22em; text-transform: uppercase; color: var(--ink-muted); margin-bottom: .3rem; }
.nn-ch-tamil { font-family: var(--font-tamil); font-size: 1.1rem; font-weight: 700; color: var(--ink-primary); line-height: 1.3; margin-bottom: .1rem; }
.nn-ch-eng { font-family: var(--font-display); font-style: italic; font-size: .88rem; color: var(--nn-blue-mid); margin-bottom: .5rem; }
.nn-ch-desc { font-size: .82rem; line-height: 1.55; color: var(--ink-secondary); margin-bottom: .6rem; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.nn-ch-footer { display: flex; justify-content: space-between; align-items: center; font-size: .7rem; color: var(--ink-muted); padding-top: .55rem; border-top: 1px solid var(--border-subtle); }

/* Book prev/next */
.nn-book-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 2.5rem; }
.nn-nav-link { display: block; padding: 1rem 1.3rem; background: var(--bg-paper); border: 1px solid rgba(26,46,90,0.2); border-radius: 4px; text-decoration: none; color: inherit; transition: all .2s ease; }
.nn-nav-link:hover { border-color: var(--nn-blue); transform: translateY(-2px); box-shadow: 0 3px 10px rgba(10,20,50,.1); }
.nn-nav-link.next { text-align: right; }
.nn-nav-link.disabled { opacity: .3; pointer-events: none; }
.nn-nav-dir { font-size: .67rem; letter-spacing: .2em; text-transform: uppercase; color: var(--ink-muted); margin-bottom: .25rem; font-family: var(--font-display); }
.nn-nav-title { font-family: var(--font-tamil); font-size: 1rem; color: var(--nn-blue); margin-bottom: .1rem; }
.nn-nav-sub { font-size: .78rem; color: var(--ink-muted); font-style: italic; font-family: var(--font-display); }

/* ---------------------------------------------------------------------------
   Chapter page — sūtra cards
   --------------------------------------------------------------------------- */
.nn-chapter-banner {
  padding: 1.75rem 2.25rem;
  border-radius: 5px;
  background: linear-gradient(135deg,#1a2e5a,#0e1e40);
  color: white;
  margin-bottom: 2rem;
  position: relative;
}
.nn-chapter-banner::after {
  content: '';
  position: absolute; right: 16px; top: 50%; transform: translateY(-50%);
  width: 13px; height: 13px; border-radius: 50%;
  background: rgba(0,0,0,.25); border: 1.5px solid rgba(255,255,255,.15);
}
.nn-ch-banner-num { font-size: .68rem; letter-spacing: .3em; text-transform: uppercase; opacity: .7; margin-bottom: .4rem; font-family: var(--font-display); }
.nn-ch-banner-tamil { font-family: var(--font-tamil); font-size: 1.5rem; font-weight: 700; margin-bottom: .15rem; }
.nn-ch-banner-eng { font-family: var(--font-display); font-style: italic; font-size: .95rem; opacity: .82; }

/* Sūtra list */
.nn-sutra-list { display: flex; flex-direction: column; gap: 1.4rem; margin-bottom: 2.5rem; }

.nn-sutra-card {
  background: var(--bg-paper);
  background-image: repeating-linear-gradient(0deg,
    rgba(26,46,90,0.015) 0px, rgba(26,46,90,0.015) 1px,
    transparent 1px, transparent 8px);
  border: 1px solid rgba(26,46,90,0.25);
  border-radius: 4px;
  padding: 1.75rem 2.25rem 1.5rem;
  box-shadow: 0 1px 3px rgba(10,20,50,0.07), 0 3px 12px rgba(10,20,50,0.06);
  position: relative;
}
.nn-sutra-card::before, .nn-sutra-card::after {
  content: ''; position: absolute; top: 50%; transform: translateY(-50%);
  width: 11px; height: 11px; border-radius: 50%;
  background: var(--bg-primary); border: 1.5px solid rgba(26,46,90,0.35);
}
.nn-sutra-card::before { left: 11px; }
.nn-sutra-card::after  { right: 11px; }

.nn-sutra-num {
  font-family: var(--font-display);
  font-size: .68rem; letter-spacing: .3em; text-transform: uppercase;
  color: var(--nn-blue); margin-bottom: .75rem; text-align: center;
}
.nn-sutra-num .snum {
  font-size: 1.25rem; letter-spacing: 0; font-weight: 700;
  margin: 0 .4em; vertical-align: middle;
}

.nn-layer-label {
  font-family: var(--font-display); font-size: .65rem;
  letter-spacing: .25em; text-transform: uppercase;
  color: var(--nn-blue); margin-bottom: .65rem; font-weight: 500;
}
.nn-sutra-layer {
  margin-bottom: 1.5rem; padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
}
.nn-sutra-layer:last-child { margin-bottom: 0; padding-bottom: 0; border-bottom: none; }

.nn-sutra-text { font-family: var(--font-tamil); font-size: 1.3rem; line-height: 1.85; color: var(--ink-primary); font-weight: 600; white-space: pre-line; }
.nn-translit-text { font-family: var(--font-body); font-style: italic; font-size: 1.05rem; line-height: 1.75; color: var(--ink-secondary); white-space: pre-line; }
.nn-rule-text { font-family: var(--font-display); font-size: 1.05rem; line-height: 1.85; color: var(--ink-primary); }
.nn-example-text { font-family: var(--font-tamil); font-size: 1rem; line-height: 1.8; color: var(--ink-secondary); white-space: pre-line; }
.nn-commentary { font-size: .95rem; line-height: 1.8; color: var(--ink-secondary); }
.nn-note { background: var(--nn-blue-pale); border-left: 3px solid var(--nn-blue-mid); padding: .85rem 1.1rem; border-radius: 2px; font-size: .93rem; line-height: 1.75; color: var(--ink-secondary); }

/* Chapter prev/next */
.nn-ch-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 2rem; }
.nn-cnav-link { display: block; padding: 1rem 1.3rem; background: var(--bg-paper); border: 1px solid rgba(26,46,90,0.2); border-radius: 4px; text-decoration: none; color: inherit; transition: all .2s ease; }
.nn-cnav-link:hover { border-color: var(--nn-blue); transform: translateY(-2px); box-shadow: 0 3px 10px rgba(10,20,50,.1); }
.nn-cnav-link.next { text-align: right; }
.nn-cnav-link.disabled { opacity: .3; pointer-events: none; }
.nn-cnav-dir { font-size: .67rem; letter-spacing: .2em; text-transform: uppercase; color: var(--ink-muted); margin-bottom: .25rem; font-family: var(--font-display); }
.nn-cnav-title { font-family: var(--font-tamil); font-size: .95rem; color: var(--nn-blue); margin-bottom: .1rem; }
.nn-cnav-sub { font-size: .75rem; color: var(--ink-muted); font-style: italic; font-family: var(--font-display); }

/* Misc */
.nn-stat-row { display: flex; justify-content: center; gap: 2.5rem; margin: 1.75rem auto 0; flex-wrap: wrap; }
.nn-stat { text-align: center; }
.nn-stat-num { font-family: var(--font-display); font-size: 1.9rem; font-weight: 700; color: var(--nn-blue); line-height: 1; margin-bottom: .2rem; }
.nn-stat-label { font-size: .67rem; letter-spacing: .2em; text-transform: uppercase; color: var(--ink-muted); }

@media (max-width: 640px) {
  .nn-books, .nn-chapter-grid { grid-template-columns: 1fr; }
  .nn-sutra-card { padding: 1.4rem 1rem; }
  .nn-ch-nav, .nn-book-nav { grid-template-columns: 1fr; }
}