:root {
  --bg: #0f1117;
  --surface: #1a1d28;
  --surface-2: #232740;
  --border: #2a2e3f;
  --text: #e8eaf0;
  --text-2: #989cb0;
  --accent: #3b82f6;
  --accent-2: #60a5fa;
  --green: #22c55e;
  --gold: #f59e0b;
  --radius: 10px;
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

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

a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Nav */
nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 100;
}
nav .logo {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
nav .logo span { color: var(--accent); }
nav .logo small {
  font-size: 0.65rem;
  font-weight: 400;
  color: var(--text-2);
  margin-left: 0.3rem;
}
nav .nav-links { display: flex; gap: 1.5rem; align-items: center; }
nav .nav-links a { color: var(--text-2); font-size: 0.9rem; }
nav .nav-links a:hover { color: var(--accent-2); text-decoration: none; }

/* Container */
.container { max-width: 1100px; margin: 0 auto; padding: 2rem; }

/* Hero */
.hero {
  text-align: center;
  padding: 4rem 2rem;
  max-width: 800px;
  margin: 0 auto;
}
.hero h1 { font-size: 2.5rem; margin-bottom: 1rem; }
.hero h1 span { color: var(--accent); }
.hero p { color: var(--text-2); font-size: 1.1rem; max-width: 600px; margin: 0 auto 2rem; }
.hero .badge {
  display: inline-block;
  background: var(--surface-2);
  border: 1px solid var(--border);
  padding: 0.4rem 1rem;
  border-radius: 20px;
  font-size: 0.8rem;
  color: var(--text-2);
  margin-bottom: 1.5rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.5rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
}
.btn-primary { background: var(--accent); color: white; }
.btn-primary:hover { background: #2563eb; text-decoration: none; }
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-outline:hover { background: var(--surface-2); text-decoration: none; }
.btn-group { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

/* Stats */
.stats {
  display: flex;
  justify-content: center;
  gap: 3rem;
  padding: 2rem 0;
  border-top: 1px solid var(--border);
  margin-top: 2rem;
}
.stat { text-align: center; }
.stat .num { font-size: 1.8rem; font-weight: 700; color: var(--accent-2); }
.stat .label { font-size: 0.85rem; color: var(--text-2); }

/* Paper Cards */
.paper-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.2rem;
}
.paper-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.3rem;
  transition: border-color 0.2s;
}
.paper-card:hover { border-color: var(--accent); }
.paper-card .meta {
  font-size: 0.75rem;
  color: var(--text-2);
  margin-bottom: 0.5rem;
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.paper-card .meta .tag {
  background: var(--surface-2);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.7rem;
}
.paper-card h3 { font-size: 1rem; margin-bottom: 0.5rem; line-height: 1.4; }
.paper-card h3 a { color: var(--text); }
.paper-card h3 a:hover { color: var(--accent-2); }
.paper-card .authors {
  font-size: 0.8rem;
  color: var(--text-2);
  margin-bottom: 0.7rem;
}
.paper-card .abstract {
  font-size: 0.8rem;
  color: var(--text-2);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  line-height: 1.5;
}
.paper-card .actions {
  margin-top: 0.8rem;
  display: flex;
  gap: 0.8rem;
}
.paper-card .actions a { font-size: 0.8rem; }

/* Section Header */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
}
.section-header h2 { font-size: 1.3rem; }
.section-header .count { color: var(--text-2); font-size: 0.85rem; }

/* Submit Page */
.submit-form {
  max-width: 600px;
  margin: 0 auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
}
.submit-form label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-2);
  margin-bottom: 0.4rem;
  font-weight: 600;
}
.submit-form input, .submit-form textarea {
  width: 100%;
  padding: 0.7rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 0.9rem;
  margin-bottom: 1.2rem;
  font-family: var(--font);
}
.submit-form textarea { min-height: 100px; resize: vertical; }
.submit-form .hint {
  font-size: 0.75rem;
  color: var(--text-2);
  margin-top: -0.8rem;
  margin-bottom: 1rem;
}
.submit-form .btn { width: 100%; justify-content: center; }

/* Paper View Page */
.paper-view { max-width: 900px; margin: 0 auto; }
.paper-view .paper-header { margin-bottom: 2rem; }
.paper-view .paper-header h1 { font-size: 1.6rem; line-height: 1.3; }
.paper-view .paper-meta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin: 1rem 0;
  font-size: 0.85rem;
  color: var(--text-2);
}
.paper-view .paper-meta span { display: flex; align-items: center; gap: 0.3rem; }
.paper-view .license-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  background: #064e3b;
  color: #6ee7b7;
  padding: 0.2rem 0.7rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
}
.paper-view .lang-toggle {
  display: flex;
  gap: 0;
  margin-bottom: 2rem;
  background: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  width: fit-content;
}
.paper-view .lang-toggle button {
  padding: 0.5rem 1.5rem;
  border: none;
  background: transparent;
  color: var(--text-2);
  font-size: 0.85rem;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.2s;
}
.paper-view .lang-toggle button.active {
  background: var(--accent);
  color: white;
}
.paper-view .paper-body h2 {
  font-size: 1.15rem;
  margin: 2rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}
.paper-view .paper-body h3 {
  font-size: 1rem;
  margin: 1.5rem 0 0.8rem;
  color: var(--accent-2);
}
.paper-view .paper-body p {
  margin-bottom: 1rem;
  color: var(--text-2);
  line-height: 1.7;
}
.paper-view .paper-body .arabic {
  direction: rtl;
  font-family: 'Amiri', 'Traditional Arabic', serif;
  font-size: 1.05rem;
  line-height: 1.8;
}
.paper-view .paper-body .arabic p { color: var(--text); }
.paper-view .paper-body img {
  max-width: 100%;
  border-radius: 6px;
  margin: 1rem 0;
  border: 1px solid var(--border);
}
.paper-view .paper-body .table-wrap {
  overflow-x: auto;
  margin: 1rem 0;
}
.paper-view .paper-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}
.paper-view .paper-body th, .paper-view .paper-body td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.7rem;
  text-align: left;
}
.paper-view .paper-body th {
  background: var(--surface-2);
  font-weight: 600;
}
.paper-view .paper-body td { color: var(--text-2); }
.paper-view .paper-body .ref-section { margin-top: 3rem; }
.paper-view .paper-body .ref-section ol {
  font-size: 0.8rem;
  color: var(--text-2);
  padding-left: 1.5rem;
}
.paper-view .paper-body .ref-section li { margin-bottom: 0.5rem; }
.paper-view .paper-body .ref-section li a { color: var(--accent-2); }
.paper-view .side-by-side {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}
@media (max-width: 768px) {
  .side-by-side { grid-template-columns: 1fr; }
}

/* Footer */
footer {
  text-align: center;
  padding: 2rem;
  border-top: 1px solid var(--border);
  color: var(--text-2);
  font-size: 0.8rem;
  margin-top: 3rem;
}
footer a { color: var(--accent-2); }

/* Responsive */
@media (max-width: 600px) {
  nav { padding: 0.8rem 1rem; }
  nav .nav-links { gap: 0.8rem; }
  .hero { padding: 2rem 1rem; }
  .hero h1 { font-size: 1.8rem; }
  .stats { gap: 1.5rem; }
  .paper-grid { grid-template-columns: 1fr; }
  .container { padding: 1rem; }
}