/* ═══════════════════════════════════════════════════════
   MWAKENYA — main.css
   Global variables, reset, typography, nav, hero, grid
   ═══════════════════════════════════════════════════════ */

/* ── Variables ─────────────────────────────────────────── */
:root {
  --color-bg:          #0d0d0d;
  --color-surface:     #161616;
  --color-surface2:    #1e1e1e;
  --color-border:      rgba(255,255,255,.08);
  --color-primary:     #8b1a1a;   /* dark red */
  --color-primary-hover: #a82020;
  --color-accent:      #c9a84c;   /* gold */
  --color-accent-dim:  rgba(201,168,76,.15);
  --color-text:        #f0ece4;
  --color-text-muted:  #888880;
  --color-text-subtle: #555550;
  --color-success:     #2e7d32;
  --color-error:       #c62828;

  --font-display: 'Bebas Neue', 'Impact', sans-serif;
  --font-body:    'Inter', system-ui, sans-serif;

  --radius-sm:  6px;
  --radius-md:  10px;
  --radius-lg:  16px;

  --shadow-card: 0 2px 12px rgba(0,0,0,.4);
  --shadow-hover: 0 6px 24px rgba(0,0,0,.5);

  --transition: 0.18s ease;
  --nav-h: 60px;
}

/* ── Reset ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }

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

/* ── Utility ───────────────────────────────────────────── */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .45rem;
  padding: .6rem 1.3rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: .9rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  white-space: nowrap;
  text-decoration: none;
}

.btn:active { transform: scale(.97); }

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}
.btn-primary:hover { background: var(--color-primary-hover); text-decoration: none; }

.btn-accent {
  background: var(--color-accent);
  color: #0d0d0d;
}
.btn-accent:hover { background: #d9b85c; text-decoration: none; }

.btn-ghost {
  background: transparent;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}
.btn-ghost:hover {
  border-color: rgba(255,255,255,.2);
  color: var(--color-text);
  text-decoration: none;
}

.btn-full { width: 100%; }
.btn:disabled { opacity: .45; cursor: not-allowed; pointer-events: none; }

/* ── Navbar ────────────────────────────────────────────── */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  padding: 0 1.5rem;
  background: rgba(13,13,13,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.navbar-brand {
  font-family: var(--font-display);
  font-size: 1.75rem;
  letter-spacing: .1em;
  color: var(--color-accent);
  text-decoration: none;
  flex-shrink: 0;
}

.navbar-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-left: auto;
}

.nav-link {
  font-size: .875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
}
.nav-link:hover, .nav-link.active { color: var(--color-text); text-decoration: none; }

.navbar-actions {
  display: flex;
  align-items: center;
  gap: .75rem;
  margin-left: 1.5rem;
}

/* ── Announcement ticker / marquee ─────────────────────── */
.marquee-bar {
  background: var(--color-primary);
  overflow: hidden;
  white-space: nowrap;
  padding: .35rem 0;
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .04em;
}

.marquee-inner {
  display: inline-block;
  animation: marquee 28s linear infinite;
}

@keyframes marquee {
  from { transform: translateX(100vw); }
  to   { transform: translateX(-100%); }
}

/* ── Hero ──────────────────────────────────────────────── */
.hero {
  text-align: center;
  padding: 4rem 1.5rem 3rem;
  max-width: 720px;
  margin: 0 auto;
}

.hero-eyebrow {
  display: inline-block;
  font-size: .75rem;
  font-weight: 700;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: var(--color-accent);
  background: var(--color-accent-dim);
  padding: .3rem .85rem;
  border-radius: 99px;
  margin-bottom: 1.25rem;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(3rem, 8vw, 5.5rem);
  line-height: 1;
  letter-spacing: .06em;
  color: var(--color-text);
  margin-bottom: .75rem;
}

.hero-title span { color: var(--color-primary); }

.hero-sub {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 460px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 2.5rem;
  flex-wrap: wrap;
}

.hero-stat strong {
  display: block;
  font-family: var(--font-display);
  font-size: 2rem;
  color: var(--color-accent);
  line-height: 1.1;
}

.hero-stat span {
  font-size: .78rem;
  color: var(--color-text-muted);
  letter-spacing: .05em;
  text-transform: uppercase;
}

/* ── Search / Filter bar ───────────────────────────────── */
.search-section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem 2rem;
}

.search-bar {
  display: flex;
  gap: .75rem;
  align-items: center;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: .5rem .75rem;
  margin-bottom: 1.25rem;
  transition: border-color var(--transition);
}

.search-bar:focus-within {
  border-color: rgba(201,168,76,.4);
}

.search-icon { color: var(--color-text-subtle); flex-shrink: 0; }

.search-input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 1rem;
  min-width: 0;
}

.search-input::placeholder { color: var(--color-text-subtle); }

.search-clear {
  background: none;
  border: none;
  color: var(--color-text-subtle);
  cursor: pointer;
  padding: .2rem;
  line-height: 1;
  display: none;
}

.search-clear.visible { display: block; }

/* University tabs */
.uni-tabs {
  display: flex;
  gap: .5rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.uni-tab {
  padding: .35rem .9rem;
  border-radius: 99px;
  font-size: .8rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-muted);
  transition: all var(--transition);
}

.uni-tab:hover {
  border-color: rgba(201,168,76,.3);
  color: var(--color-text);
}

.uni-tab.active {
  background: var(--color-accent-dim);
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* Filter row */
.filter-row {
  display: flex;
  gap: .75rem;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.filter-select {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-family: var(--font-body);
  font-size: .85rem;
  padding: .4rem .8rem;
  cursor: pointer;
  outline: none;
}

.filter-select:focus { border-color: rgba(201,168,76,.4); }

.results-count {
  font-size: .83rem;
  color: var(--color-text-subtle);
  margin-left: auto;
}

/* ── Paper Grid ────────────────────────────────────────── */
.papers-section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
}

.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}

/* ── Paper Card ────────────────────────────────────────── */
.paper-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: .85rem;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  position: relative;
  overflow: hidden;
}

.paper-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
  border-color: rgba(201,168,76,.2);
}

/* Accent strip on left edge */
.paper-card::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--color-primary);
  border-radius: 3px 0 0 3px;
  opacity: 0;
  transition: opacity var(--transition);
}

.paper-card:hover::before { opacity: 1; }

.paper-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: .5rem;
}

.paper-uni {
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--color-accent);
  background: var(--color-accent-dim);
  padding: .2rem .55rem;
  border-radius: 99px;
  white-space: nowrap;
}

.bookmark-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text-subtle);
  padding: .1rem;
  transition: color var(--transition);
  flex-shrink: 0;
}

.bookmark-btn:hover, .bookmark-btn.active { color: var(--color-accent); }

.paper-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.35;
}

.paper-meta {
  display: flex;
  gap: .75rem;
  flex-wrap: wrap;
}

.paper-meta-item {
  font-size: .78rem;
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: .25rem;
}

.paper-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: .75rem;
  border-top: 1px solid var(--color-border);
}

.paper-price {
  font-family: var(--font-display);
  font-size: 1.6rem;
  color: var(--color-accent);
  line-height: 1;
}

.paper-price small {
  font-family: var(--font-body);
  font-size: .72rem;
  color: var(--color-text-muted);
  font-weight: 400;
  display: block;
}

.paper-actions { display: flex; gap: .5rem; }

/* Solved badge */
.solved-badge {
  position: absolute;
  top: .75rem;
  right: .75rem;
  background: #2e7d32;
  color: #fff;
  font-size: .65rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  padding: .2rem .5rem;
  border-radius: 4px;
}

/* ── Skeleton loader ───────────────────────────────────── */
@keyframes shimmer {
  0%   { background-position: -400px 0; }
  100% { background-position: 400px 0; }
}

.skeleton {
  background: linear-gradient(90deg,
    var(--color-surface2) 25%,
    rgba(255,255,255,.05) 37%,
    var(--color-surface2) 63%
  );
  background-size: 800px 100%;
  animation: shimmer 1.4s infinite;
  border-radius: var(--radius-sm);
}

.skeleton-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: .85rem;
}

.skeleton-line { height: 14px; }
.skeleton-title { height: 18px; width: 85%; }
.skeleton-btn { height: 34px; width: 100px; border-radius: var(--radius-sm); }

/* ── Recently-viewed strip ─────────────────────────────── */
.recently-viewed {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem 2rem;
}

.section-label {
  font-size: .75rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--color-text-subtle);
  margin-bottom: .85rem;
}

.mini-strip {
  display: flex;
  gap: .75rem;
  overflow-x: auto;
  scrollbar-width: none;
  padding-bottom: .25rem;
}

.mini-strip::-webkit-scrollbar { display: none; }

.mini-card {
  flex-shrink: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: .65rem .9rem;
  font-size: .82rem;
  color: var(--color-text-muted);
  cursor: pointer;
  white-space: nowrap;
  transition: border-color var(--transition), color var(--transition);
  max-width: 200px;
  overflow: hidden;
  text-overflow: ellipsis;
}

.mini-card:hover { border-color: rgba(201,168,76,.3); color: var(--color-text); }

/* ── Toast notifications ───────────────────────────────── */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: .5rem;
  pointer-events: none;
}

.toast {
  background: var(--color-surface2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: .6rem 1.1rem;
  font-size: .85rem;
  color: var(--color-text);
  box-shadow: 0 4px 16px rgba(0,0,0,.5);
  pointer-events: auto;
  animation: toast-in .2s ease forwards;
  white-space: nowrap;
}

.toast.success { border-left: 3px solid var(--color-success); }
.toast.error   { border-left: 3px solid var(--color-error); }
.toast.warning { border-left: 3px solid var(--color-accent); }

@keyframes toast-in {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes toast-out {
  to { opacity: 0; transform: translateY(8px); }
}

.toast.removing { animation: toast-out .2s ease forwards; }

/* ── Footer ────────────────────────────────────────────── */
.footer {
  text-align: center;
  padding: 2rem 1.5rem;
  font-size: .82rem;
  color: var(--color-text-subtle);
  border-top: 1px solid var(--color-border);
}

.footer a { color: var(--color-text-muted); }
.footer a:hover { color: var(--color-text); }

/* ── Empty state ───────────────────────────────────────── */
.empty-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: 4rem 1rem;
  color: var(--color-text-muted);
}

.empty-icon { font-size: 3rem; margin-bottom: 1rem; }
.empty-state h3 { font-size: 1.1rem; margin-bottom: .5rem; color: var(--color-text); }
.empty-state p  { font-size: .9rem; max-width: 320px; margin: 0 auto; }

/* ── Responsive ────────────────────────────────────────── */
@media (max-width: 640px) {
  .hero { padding: 2.5rem 1rem 2rem; }
  .hero-stats { gap: 1.5rem; }
  .navbar-links { display: none; }
  .papers-grid { grid-template-columns: 1fr; }
  .filter-row { gap: .5rem; }
  .results-count { order: -1; width: 100%; margin-left: 0; }
}