:root {
  --bg: #212529;
  --bg-raised: #2b3035;
  --bg-inset: #343A40;
  --bg-mid: #495057;
  --fg: #DEE2E6;
  --fg-strong: #F8F9FA;
  --fg-soft: #adb5bd;
  --dim: #868e96;
  --border: #495057;
  --accent: #BDF226;
  --accent-text: #BDF226;
  --accent-soft: rgba(189, 242, 38, 0.10);
  --yellow: #f2f226;
  --serif: "Source Serif 4", Georgia, serif;
  --sans: "Inter", system-ui, sans-serif;
  --mono: "JetBrains Mono", monospace;
}

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

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-weight: 300;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 820px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

a { color: var(--accent-text); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
a em { color: var(--fg-soft); font-size: 0.98rem; }
a:hover em { color: var(--fg); }

/* ---------- masthead ---------- */
header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 2.2rem 0 1.2rem;
  border-bottom: 2px solid var(--fg-strong);
}
.site-name {
  font-family: var(--mono);
  font-weight: 700;
  font-size: 1.4rem;
  color: var(--fg-strong);
  letter-spacing: -0.02em;
}
.site-name::before { content: "> "; color: var(--accent-text); }
.site-name:hover { text-decoration: none; color: var(--accent-text); }

nav {
  display: flex;
  align-items: center;
  gap: 1.1rem;
}
nav a { color: var(--fg-soft); }
nav a:hover { color: var(--accent-text); }
nav a i { font-size: 1rem; vertical-align: -1px; }

/* ---------- hero ---------- */
.intro { padding: 3.2rem 0 2.8rem; }
.intro h1 {
  font-family: "Space Grotesk", var(--sans);
  font-weight: 700;
  font-size: clamp(1.7rem, 4.2vw, 2.4rem);
  line-height: 1.2;
  margin-bottom: 1rem;
  color: var(--fg-strong);
}
.intro em {
  color: var(--accent-text);
  font-family: var(--serif);
  font-style: italic;
  font-weight: 600;
}
.intro p {
  color: var(--fg-soft);
  font-size: 0.98rem;
}

/* ---------- sections ---------- */
section { padding: 1.8rem 0 2.4rem; }

.section-title {
  font-family: var(--mono);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--fg-strong);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1.4rem;
}
.section-title::before { content: ">"; color: var(--accent-text); font-weight: 700; }

.section-note {
  color: var(--dim);
  font-size: 0.82rem;
  margin: -0.9rem 0 1.2rem;
}

/* ---------- frameworks ---------- */
.framework-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
.framework {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  padding: 1.3rem 1.5rem;
  transition: border-left-color .2s;
}
.framework:hover { border-left-color: var(--fg-strong); }
.framework.muted { opacity: 0.45; }

.framework-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.3rem;
}
.framework h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--fg-strong);
}
.abbr {
  font-family: var(--sans);
  font-weight: 500;
  font-size: 0.62rem;
  letter-spacing: 0.1em;
  color: var(--fg-strong);
  background: var(--bg-mid);
  padding: 0.15rem 0.45rem;
  vertical-align: 2px;
  margin-left: 0.4rem;
}
.msc-code {
  font-family: var(--sans);
  font-weight: 200;
  font-size: 0.62rem;
  letter-spacing: 0.1em;
  color: var(--dim);
  background: var(--bg-inset);
  padding: 0.15rem 0.45rem;
  vertical-align: 2px;
  margin-left: 0.4rem;
}
.status {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-soft);
  white-space: nowrap;
}
.status.dim { color: var(--dim); }
.dots-green, .dots-yellow { font-size: 0.5rem; vertical-align: 2px; margin-right: 0.3rem; }
.dots-green { color: var(--accent-text); }
.dots-yellow { color: var(--yellow); }

.framework p { color: var(--fg-soft); font-size: 0.9rem; }

.framework-papers { margin-top: 0.9rem; }
.framework-papers-label {
  display: block;
  font-family: var(--mono);
  font-size: 0.64rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--dim);
  margin-bottom: 0.3rem;
}
.framework-papers ul { list-style: none; }
.framework-papers li {
  padding: 0.35rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.88rem;
}
.framework-papers li:last-child { border-bottom: none; }
.framework-papers a { color: var(--fg); font-weight: 400; }
.framework-papers a:hover { color: var(--accent-text); }
.paper-flag {
  font-size: 0.64rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--dim);
  margin-left: 0.5rem;
  white-space: nowrap;
}

/* ---------- progress (kept for future use) ---------- */
.progress { margin-top: 1rem; }
.progress-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.66rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--dim);
  margin-bottom: 0.3rem;
}
.progress-value { color: var(--accent-text); font-weight: 500; }
.progress-track {
  height: 4px;
  background: var(--bg-inset);
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--bg-mid), var(--accent));
}

/* ---------- software ---------- */
.software-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
.software-item {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  padding: 1.2rem 1.4rem;
}

.software-head {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  flex-wrap: wrap;
}
.software-head a {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 1.05rem;
  color: var(--fg-strong);
}
.software-head a:hover { color: var(--accent-text); }
.version-bubble {
  font-family: var(--mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  color: var(--fg-strong);
  background: var(--bg-mid);
  padding: 0.1rem 0.5rem;
  white-space: nowrap;
}
.software-head a.version-bubble {
  font-size: 0.68rem;
  color: var(--fg-strong);
}
.software-head a.version-bubble:hover {
  color: var(--accent-text);
  text-decoration: none;
}
.software-head a.dev-bubble {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  color: #d8c782;
  background: rgba(216, 199, 130, 0.08);
  border: 1px dashed rgba(216, 199, 130, 0.6);
  padding: 0.05rem 0.45rem;
}
.software-head a.dev-bubble:hover {
  color: #f1df9d;
  background: rgba(216, 199, 130, 0.15);
  border-color: #f1df9d;
}
.software-desc {
  color: var(--fg-soft);
  font-size: 0.85rem;
  margin: 0.4rem 0 0.7rem;
}
.software-links {
  display: flex;
  gap: 1.2rem;
  font-size: 0.76rem;
  font-weight: 500;
}
.software-links a {
  color: var(--fg-soft);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}
.software-links a:hover { color: var(--accent-text); text-decoration: none; }
.software-links i { color: var(--accent-text); }

/* ---------- achievements ---------- */
.achievement-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
.achievement {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-top: 3px solid var(--accent);
  padding: 1.2rem 1.3rem;
  display: flex;
  flex-direction: column;
  transition: border-top-color .2s;
}
.achievement:hover { border-top-color: var(--fg-strong); }

.badge-row {
  display: flex;
  gap: 0.4rem;
  margin-bottom: 0.7rem;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.6rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  padding: 0.2rem 0.55rem;
  border: 1px solid var(--border);
}
.badge i { font-size: 0.6rem; }
.badge.solved {
  color: var(--bg-raised);
  background: var(--accent);
  border-color: transparent;
}
.badge.record {
  color: var(--fg-strong);
  background: var(--bg-mid);
  border-color: transparent;
}
.achievement h3 {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 0.98rem;
  margin-bottom: 0.4rem;
  color: var(--fg-strong);
}
.achievement p {
  color: var(--fg-soft);
  font-size: 0.84rem;
  flex: 1;
  margin-top: 0.9rem;
}
.achievement-meta {
  color: var(--dim);
  font-size: 0.76rem;
}
.achievement-links {
  margin-top: 0.9rem;
  display: flex;
  gap: 1.1rem;
  font-size: 0.76rem;
}
.achievement-links a { color: var(--fg-soft); font-weight: 500; }
.achievement-links a:hover { color: var(--accent-text); text-decoration: none; }
.achievement-links i { color: var(--accent-text); margin-right: 0.3rem; }

/* --------- unlocked --------- */
.unlocked-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding-bottom: 0.45rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 0.4rem;
}
.unlocked-heading .group-header {
  padding: 0;
  border: 0;
  margin: 0;
  white-space: nowrap;
}
.unlocked-heading .unlocked-links,
.unlocked-heading .unlocked-links a { margin-top: 0; }
.discovery-main {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 1rem;
}
.discovery-info {
  flex: 1 1 21rem;
  min-width: 0;
}
.discovery-info .paper-title {
  margin-bottom: 0;
}
.discovery-date {
  color: var(--dim);
  font-size: 0.78rem;
  margin-top: 0.1rem;
}
.discovery-main .discovery-links {
  margin: 0 0 0 auto;
}
.discovery-main .discovery-links a { width: auto; }

.unlocked p {
  color: var(--dim);
  font-size: 0.84rem;
  font-style: italic;
  flex: 1;
}

/* ---------- papers ---------- */
.paper, .unlocked {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1rem 0.2rem;
  transition: background .15s;
}
.paper:hover { background: var(--bg-raised); }
.paper-icon {
  color: var(--dim);
  font-size: 1.1rem;
  margin-top: 0.35rem;
}
.paper:hover .paper-icon { color: var(--accent-text); }
.paper-main { flex: 1; min-width: 240px; }
.paper-title {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.02rem;
  margin-bottom: 0.1rem;
}
.paper-title a { color: var(--fg); }
.paper-title a:hover { color: var(--accent-text); text-decoration: none; }
.paper-desc {
  color: var(--fg-soft);
  font-size: 0.92rem;
  margin-bottom: 0.1rem;
}
.paper-meta {
  color: var(--fg-soft);
  font-size: 0.89rem;
  margin-top: 0.1rem;
}

.paper-meta::before { content: "> "; margin-right: 0.2rem; color: var(--accent); font-weight: 400; }

.paper-links, .unlocked-links {
  
  
  gap: 0.4rem;
  
  margin-top: 0.4rem;
align-items: flex-start; display: flex; flex-direction: row; }

.paper-links a, .unlocked-links a {
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  color: var(--fg-soft);
  border: 1px solid var(--border);
  padding: 0.2rem 0.55rem;
  white-space: nowrap;
  transition: all .15s;
  text-align: center;
}
.unlocked-links a {
  margin-top: 0.2rem;
  color: var(--dim);
  border-color: var(--bg-inset);
}
.paper-links a { width: 4.5rem; }
.paper-links a:hover, .unlocked-links a:hover {
  color: var(--accent-text);
  border-color: var(--accent-text);
  text-decoration: none;
}
.unlocked-links a:hover {
  color: var(--fg-soft);
  border-color: var(--border);
}
.arxiv-id { color: var(--dim); font-weight: 400; }

/* paper subgroups */
.paper-group, .unlocked-group { margin-bottom: 2.8rem; }
.paper-group:last-child, .unlocked-group:last-child { margin-bottom: 0; }

.group-header {
  font-family: var(--sans);
  font-weight: 500;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
  padding-bottom: 0.45rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 0.4rem;
}
.group-header::before {
  font-family: "Font Awesome 6 Free";
  font-weight: 900;
  color: var(--dim);
  margin-right: 0.5rem;
}

.group-header.elliptic-curves::before {
  content: "\f534"; /* fa-bezier-curve */
}

.group-header.physics::before {
  content: "\f5d2"; /* fa-atom */
}

/* unlocked group headers */
.group-header.high-rank::before {
  content: "\f091";
}
.group-header.solved::before {
  content: "\f00c";
}
.group-header.discoveries::before {
  content: "\f0c3"; /* fa-flask */
}

/* ---------- about ---------- */
.about-grid {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
}
.about-head {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  margin-bottom: 0.5rem;
}
.about-info h3 {
  font-family: var(--mono);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--fg-strong);
}
.about-socials {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.about-socials a { color: var(--fg-soft); }
.about-socials a:hover { color: var(--accent-text); }
.about-socials i { font-size: 1.1rem; }
.about-info p {
  color: var(--fg-soft);
  font-size: 0.9rem;
}
/* ---------- about ---------- */
.about-photo {
  position: relative;
  flex-shrink: 0;
  border: 1px solid var(--border);
  background: var(--bg-inset);
  padding: 4px;                       /* inner frame gap */
}
.about-photo::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 14px;
  height: 14px;
  border-top: 3px solid var(--accent);
  border-left: 3px solid var(--accent);
  z-index: 1;
}
.about-photo::after {
  content: "";
  position: absolute;
  bottom: 0; right: 0;
  width: 14px;
  height: 14px;
  border-bottom: 3px solid var(--accent);
  border-right: 3px solid var(--accent);
  z-index: 1;
}
.about-photo img {
  display: block;
  width: 160px;
  height: 160px;
  object-fit: cover;
  filter: grayscale(100%) contrast(1.08) brightness(0.92);
  transition: filter .3s;
}
.about-photo:hover img {
  filter: grayscale(0%) contrast(1.02) brightness(1);
}

/* -- lists -- */
ul {
  list-style: none;
  margin-bottom: 3.2rem;
}
ul:last-child {
  margin-bottom: 0.2rem;
}
.header-underline {
  padding-bottom: 0.45rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 0.4rem;
}
h2.header-underline {
  color: var(--fg);
}
h3.header-underline {
  color: var(--fg-soft);
}

/* ---------- footer ---------- */
footer {
  padding: 1.6rem 0 2.4rem;
  margin-top: 2rem;
  border-top: 1px solid var(--border);
  color: var(--dim);
  font-size: 0.78rem;
}

/* ---------- responsive ---------- */
@media (max-width: 680px) {
  .framework-grid { grid-template-columns: 1fr; }
  .achievement-grid { grid-template-columns: 1fr; }
  .software-grid { grid-template-columns: 1fr; }
  .paper { flex-wrap: wrap; }
  .paper-links { width: 100%; justify-content: flex-start; }
  .about-grid { flex-direction: column; align-items: center; text-align: center; }
  .about-head { flex-direction: column; gap: 0.7rem; }
}