/*
 * KDP Bookshelf stylesheet.
 *
 * Palette: pale green + pale orange as the two section backgrounds, a
 * medium blue as the only accent color (links, buttons, focus states),
 * and black for all body text. Everything below pulls its colors from
 * the custom properties defined in :root — to re-theme the site, edit
 * the values there rather than hunting for hardcoded hex codes.
 */
:root {
  --pale-green: #e3f3e1;
  /* Adjustable: used for borders/dividers on pale-green backgrounds (card
     borders, the mobile nav dropdown's top border). Keep it a visibly
     darker shade of --pale-green, not a different hue — these borders are
     UI boundaries (card edges, section dividers) that need ~3:1 contrast
     against --pale-green to stay perceptible (WCAG 1.4.11 Non-Text
     Contrast); pushing it too close to --pale-green's own lightness will
     make cards/dividers hard to distinguish from their background. */
  --pale-green-deep: #cfe9cb;
  --pale-orange: #fbe6d4;
  /* Adjustable: same role as --pale-green-deep above, but for
     pale-orange backgrounds (book cover image borders, the contact card's
     outline) — same contrast guidance applies. */
  --pale-orange-deep: #f6d3ac;
  /* Accent blue is used both as a text color on white and as a button
     background with white text on top of it. #3366cc was chosen (over the
     original #3d78c9) because it's the darkest "medium blue" that still
     clears the WCAG AA 4.5:1 contrast ratio against white in both
     directions (measured ~5.37:1). If this is changed, re-check contrast
     against #ffffff before shipping — anything lighter than roughly
     #3d78c9 will likely fail. */
  --accent-blue: #3366cc;
  --accent-blue-dark: #2c5a99; /* hover/focus state for accent-blue buttons and links */
  --text-color: #000000;
  --white: #ffffff;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

/* Respect the OS-level "reduce motion" setting: users who've opted out of
   animations shouldn't be forced into a smooth-scroll on anchor clicks. */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

/* Standard "sr-only" pattern: visually hides content while keeping it in
   the accessibility tree, e.g. the "(opens in a new tab)" notices on
   external links. Do not use display:none/visibility:hidden for this —
   those also hide the text from screen readers, defeating the purpose. */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: var(--text-color);
  background-color: var(--white);
  line-height: 1.6;
}

h1, h2, h3 {
  color: var(--text-color);
  margin-top: 0;
}

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

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

/* Skip-to-content link (WCAG 2.4.1). Sits off-screen at -9999px so it
   never affects layout, and jumps on-screen the moment it receives
   keyboard focus (see .skip-link:focus) — i.e. the first Tab press on the
   page reveals it. Mouse/touch users never see it. */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background-color: var(--accent-blue);
  color: var(--white);
  padding: 12px 20px;
  z-index: 1000;
  font-weight: bold;
  text-decoration: none;
  border-radius: 0 0 6px 0;
}

.skip-link:focus {
  left: 0;
}

/* ============================================================
   Header / Navigation
   Sticky header with a desktop inline nav that collapses into a
   hamburger-triggered dropdown below the 700px breakpoint (see the
   @media block further down). The open/close behavior itself lives in
   scripts/script.js — this file only controls what each state looks like.
   ============================================================ */
header {
  background-color: var(--white);
  border-bottom: 3px solid var(--accent-blue);
  position: sticky; /* also makes header the positioning context for the
                        absolutely-positioned mobile dropdown below */
  top: 0;
  z-index: 100;
}

.nav-wrap {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  flex-wrap: wrap;
}

.brand {
  font-size: 1.4rem;
  font-weight: bold;
  color: var(--text-color);
  text-decoration: none;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 28px;
  margin: 0;
  padding: 0;
  flex-wrap: wrap;
}

nav a {
  text-decoration: none;
  color: var(--text-color);
  font-weight: 600;
  padding: 6px 4px;
  border-bottom: 2px solid transparent;
  transition: border-color 0.2s ease, color 0.2s ease;
}

nav a:hover,
nav a:focus {
  color: var(--accent-blue);
  border-bottom-color: var(--accent-blue);
}

/* Hamburger button. Hidden on desktop by default; the 700px media query
   below flips this to display:flex. Kept in the DOM at all times (rather
   than injected by JS) so it's always keyboard/screen-reader reachable. */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: 2px solid transparent;
  border-radius: 6px;
  padding: 8px;
  cursor: pointer;
}

.nav-toggle-bar {
  width: 26px;
  height: 3px;
  background-color: var(--text-color);
  border-radius: 2px;
  transition: background-color 0.2s ease;
}

.nav-toggle:hover .nav-toggle-bar,
.nav-toggle:focus .nav-toggle-bar {
  background-color: var(--accent-blue);
}

/* Mobile nav breakpoint. 700px was chosen to comfortably fit the brand +
   all 4 nav links in one row above that width; adjust this single value
   if the nav items or brand text length change enough to start wrapping
   awkwardly on tablets. Nothing in scripts/script.js depends on this
   number — the JS only toggles classes/attributes, so this can be edited
   freely without touching JS. */
@media (max-width: 700px) {
  .nav-toggle {
    display: flex;
    /* Pushes the button to the right edge of the flex row instead of
       floating in the middle — needed because the (now-collapsed, empty)
       <nav> after it no longer takes up space to balance the
       justify-content: space-between on .nav-wrap. */
    margin-left: auto;
  }

  /* Dropdown panel. Hidden by default; JS toggles the .is-open class on
     click. Positioned absolute under the sticky header (top:100%) rather
     than inline, so opening it doesn't push page content down.

     right:24px lines its right edge up with the hamburger button above it
     (.nav-toggle sits at the far right of .nav-wrap, which has 24px of its
     own horizontal padding — see .nav-wrap above — so this matches that
     padding rather than the header's bare edge) instead of the panel
     hanging out past the button. width:max-content sizes the panel to its
     widest nav item (plus the 24px left/right padding below) instead of
     stretching edge-to-edge across the screen; adjust that padding value
     to make the panel a bit tighter or roomier around the text without
     affecting anything else. max-width is just a safety net so a very
     long future nav item on a very narrow phone still can't push the
     panel past the left edge of the screen. */
  nav ul {
    display: none;
    flex-direction: column;
    gap: 0;
    position: absolute;
    top: 100%;
    right: 24px;
    left: auto;
    width: max-content;
    max-width: calc(100vw - 48px);
    background-color: var(--white);
    border-top: 1px solid var(--pale-green-deep);
    border-bottom: 3px solid var(--accent-blue);
    box-shadow: 0 6px 10px rgba(0, 0, 0, 0.08);
    padding: 8px 24px;
  }

  nav ul.is-open {
    display: flex;
  }

  nav li {
    width: 100%;
  }

  nav li a {
    display: block;
    padding: 14px 4px;
    border-bottom: 1px solid var(--pale-green-deep);
  }

  nav li:last-child a {
    border-bottom: none;
  }
}

/* ============================================================
   Hero
   ============================================================ */
.hero {
  background: linear-gradient(135deg, var(--pale-green) 0%, var(--pale-orange) 100%);
  padding: 80px 24px;
  text-align: center;
}

.hero-inner {
  max-width: 760px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 2.6rem;
  margin-bottom: 16px;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 28px;
}

.btn {
  display: inline-block;
  background-color: var(--accent-blue);
  color: var(--white);
  padding: 14px 32px;
  border-radius: 6px;
  text-decoration: none;
  font-weight: bold;
  font-size: 1rem;
  border: none;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.btn:hover,
.btn:focus {
  background-color: var(--accent-blue-dark);
}

/* ============================================================
   Shared section layout (used by #bookshelf and #contact)
   ============================================================ */
section {
  padding: 70px 24px;
}

.section-inner {
  max-width: 1100px;
  margin: 0 auto;
}

.section-title {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 48px;
}

/* ============================================================
   Bookshelf
   Each book is one .book-card inside the .book-grid. To add a new book,
   duplicate a <article class="book-card"> block in index.html — this CSS
   needs no changes, the grid reflows automatically.
   ============================================================ */
#bookshelf {
  background-color: var(--pale-green);
}

/* auto-fit + minmax(280px, 1fr): cards are never narrower than 280px: below
   that the grid drops to fewer columns instead of squeezing cards further.
   Raise the 280px minimum if book cover art needs more room; lower it to
   fit more columns on wide screens. */
/* Amazon Associates disclosure, required wording — see the HTML comment
   above the <p class="affiliate-disclosure"> in index.html. */
.affiliate-disclosure {
  text-align: center;
  font-size: 0.9rem;
  font-style: italic;
  margin: -28px 0 40px;
}

.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 40px;
}

.book-card {
  background-color: var(--white);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
  border: 1px solid var(--pale-green-deep);
  display: flex;
  flex-direction: column;
}

/* Fixed height + object-fit:cover crops every cover image to the same
   aspect ratio regardless of its original dimensions, so mismatched cover
   art (e.g. a portrait vs. a near-square cover) still lines up evenly
   across cards. Adjust the 340px height if cover art is being cropped too
   aggressively. */
.book-card img {
  width: 100%;
  height: 340px;
  object-fit: cover;
  border-bottom: 3px solid var(--pale-orange-deep);
}

.book-card-body {
  padding: 22px;
  display: flex;
  flex-direction: column;
  flex-grow: 1; /* lets the card body fill remaining height so... */
}

.book-card h3 {
  font-size: 1.3rem;
  margin-bottom: 10px;
}

.book-card p {
  flex-grow: 1; /* ...and this pushes the "Buy on Amazon" button to the
                    bottom of every card, even when description lengths
                    differ between books. */
  margin-bottom: 20px;
}

.amazon-btn {
  display: inline-block;
  background-color: var(--accent-blue);
  color: var(--white);
  text-decoration: none;
  text-align: center;
  padding: 12px 20px;
  border-radius: 6px;
  font-weight: bold;
  transition: background-color 0.2s ease;
}

.amazon-btn:hover,
.amazon-btn:focus {
  background-color: var(--accent-blue-dark);
}

/* ============================================================
   Contact
   Formspree-backed contact form. The success/error messages and
   per-field validation errors below are populated at runtime by the
   @formspree/ajax library (see scripts/script.js) — this file only
   defines how they look once populated.
   ============================================================ */
#contact {
  background-color: var(--pale-orange);
}

.contact-form {
  max-width: 600px;
  margin: 0 auto;
  background-color: var(--white);
  padding: 36px;
  border-radius: 10px;
  border: 1px solid var(--pale-orange-deep);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
}

.form-message {
  max-width: 600px;
  margin: 0 auto;
}

/* The success/error <div>s in index.html start empty and are filled in by
   Formspree's JS on submit. :not(:empty) means they take up zero visual
   space (no padding/border/margin) until that happens, so there's no need
   for a separate "hidden" class to toggle — an empty div already collapses
   to nothing. */
.form-message:not(:empty) {
  padding: 14px 18px;
  border-radius: 6px;
  margin-bottom: 20px;
  font-weight: 600;
}

.form-message-success:not(:empty) {
  background-color: var(--pale-green);
  border: 1px solid var(--pale-green-deep);
  color: var(--text-color);
}

.form-message-error:not(:empty) {
  background-color: var(--pale-orange);
  border: 1px solid var(--accent-blue);
  color: var(--text-color);
}

.field-error {
  display: block;
  color: var(--accent-blue-dark);
  font-size: 0.85rem;
  margin-top: 4px;
  font-weight: 600;
}

.form-note {
  margin: 0 0 20px;
  font-size: 0.9rem;
}

.form-group {
  margin-bottom: 20px;
}

label {
  display: block;
  font-weight: 600;
  margin-bottom: 6px;
}

input[type="text"],
input[type="email"],
textarea {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--pale-green-deep);
  border-radius: 6px;
  font-family: inherit;
  font-size: 1rem;
  color: var(--text-color);
  background-color: var(--white);
}

input[type="text"]:focus,
input[type="email"]:focus,
textarea:focus {
  outline: 2px solid var(--accent-blue);
  outline-offset: 1px;
  border-color: var(--accent-blue);
}

/* aria-invalid is set by Formspree's JS when a field fails validation.
   The thicker border is a secondary (non-color-only) cue to pair with the
   .field-error text below each field — relying on the border color change
   alone would fail WCAG 1.4.1 (Use of Color). */
input[aria-invalid="true"],
textarea[aria-invalid="true"] {
  border-color: var(--accent-blue);
  border-width: 2px;
}

textarea {
  resize: vertical;
  min-height: 140px;
}

.submit-btn {
  background-color: var(--accent-blue);
  color: var(--white);
  border: none;
  padding: 14px 32px;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: bold;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

/* Disabled controls are exempt from WCAG's contrast requirements, but
   illegible text still makes for a confusing "is this broken?" moment, so
   this keeps the label readable (black text) instead of the default
   white-on-pale-green, which measures under 2:1. */
.submit-btn:disabled {
  background-color: var(--pale-green-deep);
  color: var(--text-color);
  opacity: 0.8;
  cursor: not-allowed;
}

.submit-btn:hover,
.submit-btn:focus {
  background-color: var(--accent-blue-dark);
}

/* ============================================================
   Footer
   ============================================================ */
footer {
  background-color: var(--white);
  text-align: center;
  padding: 24px;
  border-top: 1px solid var(--pale-green-deep);
  font-size: 0.9rem;
}

footer a {
  color: var(--accent-blue);
  text-decoration: none;
}

footer a:hover,
footer a:focus {
  text-decoration: underline;
}

/* Separate, smaller breakpoint from the nav's 700px above — this one only
   tightens hero/section padding for small phones and is intentionally
   independent of the nav breakpoint. */
@media (max-width: 600px) {
  .hero {
    padding: 56px 20px;
  }

  .hero h1 {
    font-size: 2rem;
  }

  section {
    padding: 50px 20px;
  }
}