/* =====================================================================
   Research methodology book page — on top of books/word/style.css (same layout).
   Adds: the cover colours and the two reading modes of the preview
   (book = flipbook, pdf = pages one under the other), on computers and
   phones alike (app.js puts .mode-book or .mode-pdf on #preview).
===================================================================== */
:root{
  --brand: #14223F;            /* navy from the cover */
  --brand-strong: #0B1530;
  --brand-soft: #E8EBF2;
  --gold: #C8961E;
  --gold-soft: #FBF3DF;
  --preview-bg: #E4DED2;
  --side-bg: #FAF8F3;
  --page-bg: #F4F1EA;
}

.bk-sub{ margin: 0; font-size: .92rem; font-weight: 800; color: var(--brand); }

/* two columns, filled top to bottom */
.bk-excel .bk-chapters ol{ grid-template-rows: repeat(var(--rows, 6), auto); }
.bk-chapters li span{ background: var(--brand); }
.bk-chapters li:nth-child(3n+2) span{ background: #3A4D75; }
.bk-chapters li:nth-child(3n) span{ background: var(--gold); color: var(--brand-strong); }

/* ---------- order block (buttons and contact window come from the Word page) ---------- */
.order-mail{ background: linear-gradient(135deg, #2C4272 0%, var(--brand) 55%, var(--brand-strong) 100%); }
.price-num{ color: var(--brand-strong); }

/* ---------- reading mode switch (book / pdf) ---------- */
.md-switch{
  display: inline-flex; padding: 3px; gap: 3px;
  border: 1px solid var(--line-strong); border-radius: 11px;
  background: var(--surface);
}
.md-btn{
  display: inline-flex; align-items: center; gap: 6px;
  height: 30px; padding: 0 11px;
  border: 0; border-radius: 8px;
  background: transparent; color: var(--ink-soft);
  font-family: inherit; font-size: .84rem; font-weight: 800;
  cursor: pointer;
}
.md-btn svg{ width: 17px; height: 17px; }
.md-btn:hover{ color: var(--brand); }
.md-btn[aria-pressed="true"]{ background: var(--brand); color: #fff; }
.md-btn:focus-visible{ outline: 2px solid var(--gold); outline-offset: 2px; }

/* last page of the book */
.fb-page-end, .pv-list-end{ background: linear-gradient(160deg, var(--brand) 0%, var(--brand-strong) 100%); }

/* ---------- PDF mode (computers): pages one under the other, scrolled inside the reader ---------- */
@media (min-width: 861px){
  .bk-preview.mode-pdf .fb-stage, .bk-preview.mode-pdf .fb-nav, .bk-preview.mode-pdf .fb-only{ display: none; }
  .bk-preview.mode-pdf .pv-list{
    display: flex; flex-direction: column; align-items: center; gap: 14px;
    flex: 1; min-height: 0; overflow: auto;
    padding: 18px 24px 28px;
  }
  .bk-preview.mode-pdf .pv-pg{
    position: relative; flex-shrink: 0;
    width: min(100%, calc(780px * var(--z, 1)));
    background: #fff; box-shadow: 0 2px 10px rgba(19,40,58,.16);
  }
  .bk-preview.mode-pdf .pv-list.zoomed{ align-items: flex-start; }
  .bk-preview.mode-pdf .pv-list.zoomed .pv-pg{ width: calc(780px * var(--z, 1)); max-width: none; margin: 0 auto; }
  .bk-preview.mode-pdf .pv-pg img{ display: block; width: 100%; height: 100%; user-select: none; -webkit-user-drag: none; }
  .bk-preview.mode-pdf .pv-list-end{ position: relative; flex-shrink: 0; width: min(100%, 780px); min-height: 260px; border-radius: 16px; }
  .bk-preview.mode-pdf .pv-list-status{ margin: 60px 0; font-weight: 700; color: var(--ink-soft); }
}

/* ---------- phones: the switch stays visible; book mode shows the flipbook ---------- */
@media (max-width: 860px){
  .bk-preview .pv-tools{ display: inline-flex; }
  .bk-preview .pv-tools .fb-tool{ display: none; }
  .bk-preview .pv-bar{ position: sticky; top: var(--top-h); z-index: 4; background: rgba(244,241,234,.96); backdrop-filter: blur(8px); flex-wrap: wrap; }
  .md-btn{ padding: 0 9px; }
  .bk-preview.mode-book .pv-list{ display: none; }
  .bk-preview.mode-book .fb-stage{
    display: flex;
    height: calc(100svh - var(--top-h) - 150px); min-height: 360px;
    padding: 10px 8px 4px;
  }
  .bk-preview.mode-book .fb-nav{ display: flex; padding-bottom: 12px; }
  .bk-preview.mode-book .pv-tools .fb-tool-fs{ display: inline-flex; }
}
@media (max-width: 420px){
  .md-btn span{ display: none; }
}
.m-cta{ background: linear-gradient(135deg, #2C4272 0%, var(--brand) 55%, var(--brand-strong) 100%); }