:root {
  --backgr:  #f7f7f5;
  --backgr2: none;
  --surface: #ffffff;
  --text:    #111827;
  --muted:   #4b5563;
  --navy:    #0b1f3b;
  --teal:    #0f766e;
  --ok:      none;
  --focus:   #2563eb;
  --line:    #e5e7eb;
  --shadow:  0 8px 24px rgba(17, 24, 39, .10);
  --shadow2: 0 8px 24px rgba(17, 24, 39, .25);
  --radius:  14px;
  --gap:     26px;
  --gap2:    54px;
  --offset: 113px;
  --max:   1120px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
}

* {
  box-sizing: border-box;
  margin: 0;
}
@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
    scroll-behavior: auto !important
  }
}

html, body {height: 100%}

body {
  font-family: var(--sans);
  color:       var(--text);
  background:  var(--backgr);



  line-height: 1.55;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1 0 auto;
  padding: var(--gap) 0 var(--gap2);
}

#main {
  margin-top: var(--offset);
}

a {color: inherit}

h1 {
  margin: 0 0 10px;
  line-height: 1.15;
  letter-spacing: -.02em;
  font-size: clamp(1.6rem, 2.5vw, 2.3rem)
}

h2 {
  margin: 0 0 6px;
  font-size: 1.25rem
}

details {margin-top: 8px}

details > summary {
  cursor: pointer;
  font-weight: 700
}

p {
  margin-block-start: 10px;
  margin-block-end: 12px;
}

ul {
  margin-block-start: 0;
  margin-block-end: 3px;
  padding-inline-start: 40px;
}

[id] {scroll-margin-top: var(--offset);}

.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 20px
}

.skip {
  position: absolute;
  left: -999px;
  top: 10px;
  background: var(--surface);
  border: 1px solid var(--line);
  padding: 10px 12px;
  border-radius: 10px;
  z-index: 1000;
}
.skip:focus {
  left: 10px;
  outline: 3px solid var(--focus);
  outline-offset: 2px
}

.hdr {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  background: rgba(247, 247, 245, .86);
  backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.hdr-in {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0
}

.brand {padding-left: 20px}

.brand-link {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  position: relative;
  top: -5px;
  left: -7px;
  padding: 10px 14px;
  margin: 0 0 -10px;
  border-radius: var(--radius);
  border: 1px solid rgba(11, 31, 59, 0);
  transition: transform .16s ease, box-shadow .16s ease;
}
a.brand-link:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow);
  border-color: rgba(11, 31, 59, .18);
}

.brand-mark {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  min-width: 40px;
  border-radius: 12px;
  color: #fff;
  background: linear-gradient(135deg, var(--navy), var(--teal));
  font-weight: 800;
  letter-spacing: .5px;
}

.brand-title {
  display: block;
  font-weight: 800
}

.brand-subtitle {
  display: block;
  font-size: .9rem;
  color: var(--muted)
}

.top-nav {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: flex-end;
  padding-right: 20px;
}

.link_USTP {
  position: relative;
  top: -5px;
  left: -5px;
  padding: 10px 10px 2px;
  margin: 0 0 -10px;
  border-radius: var(--radius);
  border: 1px solid rgba(11, 31, 59, 0);
  transition: transform .16s ease, box-shadow .16s ease;
}
.link_USTP:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow);
  border-color: rgba(11, 31, 59, .18);
}

.logo_USTP {height: 45px;}

.hero {
  display: grid;
  grid-template-columns: 1.55fr .9fr;
  gap: 18px;
  align-items: stretch;
  margin: 0 0 var(--gap);
}
@media (max-width: 900px) {
  .hero {grid-template-columns: 1fr}
}

.hero-copy {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}

.hero-panel {
  background: linear-gradient(180deg, rgba(11, 31, 59, .06), rgba(15, 118, 110, .05));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}

.h1-sub {
  font-weight: 650;
  color: var(--muted)
}

.lead {
  margin: 0 0 14px;
  font-size: 1.05rem;
  color: var(--muted)
}

.section {margin-top: 28px}

.section-header {margin-bottom: 12px}

.muted {color: var(--muted)}

.breadcrumbs {margin-bottom: var(--gap);}

.cta-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.in-page-nav {margin: var(--gap) 0;}

.page-header {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 14px;
  border-radius: 12px;
  border: 1px solid rgba(11, 31, 59, .18);
  background: linear-gradient(135deg, var(--navy), var(--teal));
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  transition: transform .16s ease, box-shadow .16s ease, filter .16s ease;
}
a.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow2);
  filter: brightness(1.2);
}
.btn:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px
}

.btn-small {
  padding: 8px 10px;
  border-radius: 10px;
  font-weight: 700
}

.btn-ghost {
  background: transparent;
  color: var(--navy);
  border: 1px solid rgba(11, 31, 59, .25);
}
a.btn-ghost:hover {
  background: rgba(11, 31, 59, .06)
}

.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
  position: relative;
}

.card h3 {
  margin: 0;
  font-size: 1.5rem
}

.card h4 {
  margin: 0 0 8px;
  font-size: 1.1rem;
  font-weight: normal;
}

.card a {
  text-decoration: none
}

.card a.booktitle {
  position: relative;
  display: block;
  text-decoration: none;
  padding: 5px 10px;
  left: -5px;
  border-radius: var(--radius);
  border: 1px solid rgba(11, 31, 59, 0);
  transition: transform .16s ease, box-shadow .16s ease;
}
.card a.booktitle:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow);
  background: rgba(75, 85, 99, .05);
  border-color: rgba(11, 31, 59, .18);
}

.card-list {
  margin: 10px 0 0;
  padding-left: 18px;
  color: var(--muted)
}

.card-book {
  display: grid;
  grid-template-columns: 223px 1fr;
  gap: 16px;
  align-items: stretch;
}
@media (max-width: 520px) {
  .card-book {grid-template-columns: 1fr;}
}

.card-book-media {
  display: flex;
  align-items: flex-start;
}

.card-book-cover {
  display: block;
  position: relative;
  top: 2px;
  width: 223px;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--line);
  transition: transform .16s ease, box-shadow .16s ease;
}
@media (max-width: 520px) {
  .card-book-cover {
    width: 100%;
    max-width: none;
  }
}
.card-book-cover:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow2);
}

.card-book-body .card-header {margin-bottom: 6px;}

.card-description {margin-left: 5px;}

.card-book-body {
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.card-book-body > div.card-description {margin-bottom: 20px;}

.card-book .card-footer {margin-top: auto;}

.card-footer {margin-top: 20px;}

.two-col {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px
}
@media (max-width: 900px) {
  .two-col {grid-template-columns: 1fr}
}

.one-col {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px
}

.panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}

.panel h3 {
  margin: 0 0 8px;
  font-size: 1.05rem
}

.facts {
  margin: 0;
  display: grid;
  gap: 12px
}

.facts dt {
  font-size: .85rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: .08em
}

.facts dd {
  margin: 2px 0 0;
  font-weight: 650
}

.trust-bar {
  margin-top: 16px;
  margin-bottom: var(--gap);
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}
@media (max-width: 900px) {
  .trust-bar {grid-template-columns: 1fr}
}

.trust-item strong {
  display: block
}

.trust-item span {
  display: block;
  font-size: .95rem
}

.list-cards {
  display: grid;
  gap: 10px
}

.list-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 14px;
  transition: transform .16s ease;
}
.list-card:hover {transform: translateY(-1px)}

.list-card h3 {
  margin: 0 0 4px;
  font-size: 1.05rem
}

.list-card p {
  margin: 0
}

.code {
  font-family: var(--mono);
  background: rgba(11, 31, 59, .06);
  border: 1px solid rgba(11, 31, 59, .12);
  border-radius: 12px;
  padding: 12px;
  margin-bottom: 0;
  overflow: auto;
}

.pager {
  margin-top: var(--gap);
  display: flex;
  justify-content: space-between;
  gap: 12px;
}

.site-footer {
  margin-top: var(--gap);
  border-top: 1px solid var(--line);
  padding: 18px 0;
  background: rgba(255, 255, 255, .7);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap
}

.panel > p {
  margin-top: 0;
  margin-bottom: 0;
}

.footer-nav {
  display: flex;
  gap: 14px;
  flex-wrap: wrap
}

.footer-nav a {
  color: var(--muted);
  text-decoration: none
}
.footer-nav a:hover {text-decoration: underline}