/* ========== Reset & base ========== */
*,
*::before,
*::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background 0.3s ease, color 0.3s ease;
}

h1, h2, h3 { line-height: 1.25; margin: 0; font-weight: 600; letter-spacing: -0.015em; }
p { margin: 0; }
a { color: var(--accent); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--accent-hover); }
ul, ol { margin: 0; padding: 0; list-style: none; }

/* ========== Theme tokens — blue palette ========== */
:root {
  /* Light theme (default) */
  --bg: #f5f7ff;
  --bg-alt: #edf0fc;
  --surface: #ffffff;
  --surface-2: #f0f3fb;
  --border: #c8d3ed;
  --border-soft: #d6dff0;
  --text: #0d1626;
  --text-dim: #475270;
  --text-faint: #8a93b0;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-soft: rgba(37, 99, 235, 0.09);
  --accent-2: #0891b2;
  --accent-2-soft: rgba(8, 145, 178, 0.10);
  --accent-3: #e11d48;
  --shadow: 0 1px 2px rgba(0,0,0,0.04), 0 12px 32px rgba(30,60,140,0.09);
  --shadow-soft: 0 4px 16px rgba(37, 99, 235, 0.10);
}

[data-theme='dark'] {
  --bg: #0c1220;
  --bg-alt: #101828;
  --surface: #15213a;
  --surface-2: #1b2c4a;
  --border: #263554;
  --border-soft: #1f2e48;
  --text: #e2e8f8;
  --text-dim: #8da3cc;
  --text-faint: #546280;
  --accent: #5aa4f8;        /* vivid blue */
  --accent-hover: #7ebdfc;
  --accent-soft: rgba(90, 164, 248, 0.14);
  --accent-2: #38d0e8;      /* vivid cyan */
  --accent-2-soft: rgba(56, 208, 232, 0.12);
  --accent-3: #fb7185;      /* vivid rose */
  --shadow: 0 1px 2px rgba(0,0,0,0.5), 0 12px 32px rgba(0,0,0,0.45);
  --shadow-soft: 0 4px 16px rgba(90, 164, 248, 0.15);
}

/* ========== Layout ========== */
.container {
  width: 100%;
  max-width: 980px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 88px 0;
  border-top: 1px solid var(--border);
  position: relative;
}

.section-alt {
  background: var(--bg-alt);
  overflow: hidden;
}

.section-alt::before {
  content: '';
  position: absolute;
  top: -120px;
  right: -120px;
  width: 360px;
  height: 360px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-soft) 0%, transparent 70%);
  pointer-events: none;
}

#chat.section-alt::before {
  background: radial-gradient(circle, var(--accent-2-soft) 0%, transparent 70%);
  top: auto;
  bottom: -120px;
  right: auto;
  left: -120px;
}

.section-head {
  margin-bottom: 48px;
  max-width: 640px;
  position: relative;
  z-index: 1;
}

.section-num {
  display: inline-block;
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 0.8rem;
  color: var(--accent);
  letter-spacing: 0.12em;
  margin-bottom: 10px;
  font-weight: 500;
}

.section-head h2 {
  font-size: clamp(1.5rem, 3vw, 1.9rem);
  margin-bottom: 8px;
  font-weight: 700;
}

.section-head p {
  color: var(--text-dim);
  font-size: 0.98rem;
}

/* ========== Nav ========== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  font-weight: 600;
}

.brand:hover { color: var(--text); }

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  overflow: hidden;
  flex-shrink: 0;
}

.brand-mark img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.brand-name { font-size: 0.93rem; }

.nav-links {
  display: flex;
  gap: 24px;
}

.nav-links a {
  color: var(--text-dim);
  font-size: 0.9rem;
  font-weight: 500;
}

.nav-links a:hover { color: var(--text); }

.nav-controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.lang-switcher {
  display: inline-flex;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2px;
  background: transparent;
}

.lang-switcher button {
  background: transparent;
  border: none;
  color: var(--text-faint);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  padding: 5px 9px;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 500;
  letter-spacing: 0.06em;
  transition: all 0.18s ease;
}

.lang-switcher button:hover {
  color: var(--text-dim);
}

.lang-switcher button.active {
  background: var(--accent-soft);
  color: var(--accent);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.2s ease;
}

.theme-toggle:hover {
  color: var(--accent);
  border-color: var(--accent);
}

.theme-toggle svg { width: 16px; height: 16px; }
.theme-toggle .icon-sun { display: block; }
.theme-toggle .icon-moon { display: none; }
[data-theme='light'] .theme-toggle .icon-sun { display: none; }
[data-theme='light'] .theme-toggle .icon-moon { display: block; }

@media (max-width: 720px) {
  .brand-name { display: none; }
  .nav-links { gap: 14px; }
  .nav-links a { font-size: 0.82rem; }
}

@media (max-width: 540px) {
  .nav-links { display: none; }
}

/* ========== Hero ========== */
.hero {
  padding: 72px 0 64px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -80px;
  right: -100px;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-soft) 0%, transparent 65%);
  pointer-events: none;
  z-index: 0;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -120px;
  left: -80px;
  width: 320px;
  height: 320px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-2-soft) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

.hero .container { position: relative; z-index: 1; }

.hero-grid {
  display: flex;
  align-items: center;
  gap: 36px;
}

.hero-image {
  flex-shrink: 0;
  width: 140px;
  height: 140px;
  position: relative;
}

.hero-image::before {
  content: '';
  position: absolute;
  inset: -3px;
  border-radius: 22px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  z-index: 0;
  opacity: 0.85;
}

.hero-image img {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 19px;
  display: block;
  box-shadow: var(--shadow);
}

.hero-content { flex: 1; min-width: 0; }

.hero h1 {
  font-size: clamp(1.6rem, 3.5vw, 1.95rem);
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text);
}

.tagline {
  font-size: 1rem;
  color: var(--text-dim);
  margin-bottom: 18px;
  font-weight: 400;
}

.tagline .role {
  color: var(--accent);
  font-weight: 600;
}

.tagline-sep {
  color: var(--text-faint);
  margin: 0 4px;
}

.lede {
  max-width: 600px;
  font-size: 0.97rem;
  color: var(--text-dim);
  margin-bottom: 24px;
  line-height: 1.65;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 9px;
  font-weight: 500;
  font-size: 0.9rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-3));
  color: #fff;
}

.btn-primary:hover {
  color: #fff;
  transform: translateY(-1px);
  box-shadow: var(--shadow-soft);
}

.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 28px;
  color: var(--text-faint);
  font-size: 0.95rem;
}

.hero-meta li {
  display: inline-flex;
  align-items: center;
  gap: 14px;
}

.hero-meta svg {
  width: 17px;
  height: 17px;
  flex-shrink: 0;
  vertical-align: middle;
}

.hero-meta a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--text-dim);
}
.hero-meta a:hover { color: var(--accent); }

@media (max-width: 640px) {
  .hero { padding: 56px 0 56px; }
  .hero-grid {
    flex-direction: column;
    align-items: flex-start;
    gap: 20px;
  }
  .hero-image { width: 110px; height: 110px; }
  .hero-meta { gap: 10px 18px; }
}

/* ========== Timeline ========== */
.timeline {
  position: relative;
  padding-left: 32px;
}

.timeline::before {
  content: '';
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 7px;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent) 0%, var(--accent-2) 100%);
  opacity: 0.4;
}

.timeline-item {
  position: relative;
  padding-bottom: 36px;
}

.timeline-item:last-child { padding-bottom: 0; }

.timeline-marker {
  position: absolute;
  left: -32px;
  top: 6px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--accent);
  box-shadow: 0 0 0 4px var(--bg);
  transition: all 0.2s ease;
}

.section-alt .timeline-marker { box-shadow: 0 0 0 4px var(--bg-alt); }

.timeline-item:hover .timeline-marker {
  background: var(--accent);
  transform: scale(1.15);
}

.timeline-content h3 {
  font-size: 1.1rem;
  margin-bottom: 4px;
  color: var(--text);
  font-weight: 600;
}

.timeline-content .company {
  color: var(--accent);
  font-weight: 500;
}

.timeline-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.74rem;
  color: var(--text-faint);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.timeline-content p {
  color: var(--text-dim);
  margin: 10px 0;
  font-size: 0.94rem;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 12px;
}

.tag-list li {
  font-size: 0.76rem;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-dim);
  font-family: 'JetBrains Mono', monospace;
  transition: all 0.2s ease;
}

.tag-list li:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Education card */
.education-card {
  margin-top: 44px;
  display: flex;
  gap: 20px;
  padding: 22px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  position: relative;
  overflow: hidden;
}

.education-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--accent-2), var(--accent));
}

.education-icon {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--accent-2-soft);
  color: var(--accent-2);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.education-icon svg { width: 22px; height: 22px; }

.education-card h3 {
  font-size: 1rem;
  margin-bottom: 6px;
  font-weight: 600;
}

.education-meta {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: var(--text-faint);
  margin-bottom: 8px;
}

.education-card p { color: var(--text-dim); font-size: 0.92rem; }

/* ========== Projects ========== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 18px;
}

.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px;
  transition: all 0.25s ease;
  position: relative;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.project-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  opacity: 0;
  transition: opacity 0.25s ease;
}

.project-card:hover {
  border-color: var(--border-soft);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.project-card:hover::after { opacity: 1; }

.project-tag {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 12px;
  align-self: flex-start;
  font-weight: 500;
}

.project-card h3 {
  font-size: 1.05rem;
  margin-bottom: 8px;
  font-weight: 600;
}

.project-card > p {
  color: var(--text-dim);
  font-size: 0.92rem;
  flex-grow: 1;
}

/* ========== Skills ========== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
}

.skill-group {
  padding: 22px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  position: relative;
  transition: all 0.2s ease;
}

.skill-group:hover {
  border-color: var(--border-soft);
  box-shadow: var(--shadow-soft);
}

.skill-group h3 {
  font-size: 0.9rem;
  font-family: 'JetBrains Mono', monospace;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent);
  margin-bottom: 14px;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 8px;
}

.skill-group h3::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent);
}

.skill-group:nth-child(2n) h3 { color: var(--accent-2); }
.skill-group:nth-child(2n) h3::before {
  background: var(--accent-2);
  box-shadow: 0 0 8px var(--accent-2);
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.skill-tags li {
  font-size: 0.83rem;
  padding: 4px 11px;
  border-radius: 999px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  transition: all 0.2s ease;
}

.skill-tags li:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ========== Chat widget ========== */
.chat-widget {
  max-width: 720px;
  margin: 0 auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

[data-theme='dark'] .chat-widget {
  background: #1b2c4a;
  border-color: #2e4270;
  box-shadow: 0 0 0 1px rgba(255,255,255,0.04), 0 8px 32px rgba(0,0,0,0.5);
}

.chat-widget::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-2), transparent);
  z-index: 1;
}

/* Toolbar with clear button */
.chat-toolbar {
  display: flex;
  justify-content: flex-end;
  padding: 10px 14px 0;
}

.chat-clear {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font: inherit;
  font-size: 0.78rem;
  color: var(--text-dim);
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px 6px;
  border-radius: 6px;
  opacity: 0.6;
  transition: opacity 0.15s ease, color 0.15s ease;
}

.chat-clear svg { width: 13px; height: 13px; flex-shrink: 0; }
.chat-clear:hover { opacity: 1; color: var(--accent); }
.chat-clear:disabled { pointer-events: none; opacity: 0.3; }

/* Messages area */
.chat-messages {
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 240px;
  max-height: 460px;
  overflow-y: auto;
  padding: 10px 18px 16px;
  scroll-behavior: smooth;
  overscroll-behavior: contain;
}

.chat-messages::-webkit-scrollbar { width: 4px; }
.chat-messages::-webkit-scrollbar-track { background: transparent; }
.chat-messages::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 4px;
}

/* Bubble entrance animation */
@keyframes bubbleIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.chat-bubble {
  padding: 11px 15px;
  border-radius: 16px;
  font-size: 0.92rem;
  line-height: 1.55;
  max-width: 82%;
  white-space: pre-wrap;
  word-break: break-word;
  animation: bubbleIn 0.18s ease-out;
}

.chat-bubble.chat-user {
  background: var(--accent-2-soft);
  color: var(--text);
  align-self: flex-end;
  border-bottom-right-radius: 4px;
}

.chat-bubble.chat-bot {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  align-self: flex-start;
  border-bottom-left-radius: 4px;
}

.chat-bubble.chat-error {
  border-color: #c33 !important;
  color: #c33 !important;
}

.chat-bubble.chat-typing {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 13px 16px;
}

/* Streaming cursor */
.chat-cursor {
  display: inline-block;
  width: 2px;
  height: 0.9em;
  background: var(--accent);
  border-radius: 1px;
  margin-left: 2px;
  vertical-align: text-bottom;
  animation: blink 0.8s ease-in-out infinite;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0; }
}

/* Typing dots */
.dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-2);
  animation: pulse 1.2s infinite ease-in-out;
}

.dot:nth-child(2) { animation-delay: 0.15s; }
.dot:nth-child(3) { animation-delay: 0.3s; }

@keyframes pulse {
  0%, 80%, 100% { opacity: 0.3; transform: translateY(0); }
  40%           { opacity: 1;   transform: translateY(-3px); }
}

/* Suggestion pills */
.chat-suggestions {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  padding: 0 18px 4px;
}

.chat-suggestion {
  font: inherit;
  font-size: 0.8rem;
  padding: 5px 13px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text-dim);
  cursor: pointer;
  transition: border-color 0.15s ease, color 0.15s ease, background 0.15s ease;
}

.chat-suggestion:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
}

/* Input row */
.chat-input-row {
  display: flex;
  gap: 8px;
  padding: 10px 14px 12px;
  border-top: 1px solid var(--border);
}

.chat-input {
  flex: 1;
  font: inherit;
  font-size: 0.93rem;
  padding: 10px 14px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.chat-input::placeholder { color: var(--text-dim); opacity: 0.7; }
.chat-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
.chat-input:disabled { opacity: 0.55; cursor: not-allowed; }

.chat-send {
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 10px 20px;
  border-radius: 12px;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  flex-shrink: 0;
  transition: filter 0.15s ease, transform 0.07s ease;
}

.chat-send:hover  { filter: brightness(1.1); }
.chat-send:active { transform: translateY(1px); }
.chat-send:disabled { opacity: 0.5; cursor: not-allowed; }

/* Disclaimer */
.chat-disclaimer {
  font-size: 0.75rem;
  color: var(--text-dim);
  text-align: center;
  margin: 0;
  padding: 0 18px 14px;
  line-height: 1.5;
  opacity: 0.75;
}

/* Not-configured notice */
.chat-notice {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
  padding: 36px 28px;
  background: var(--surface);
  border: 1px dashed var(--border);
  border-radius: 18px;
}

.chat-notice h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.chat-notice p {
  color: var(--text-dim);
  font-size: 0.92rem;
}

/* ========== Footer ========== */
.footer {
  padding: 36px 0;
  border-top: 1px solid var(--border);
  background: var(--bg);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.86rem;
  color: var(--text-faint);
}

.footer-links {
  display: flex;
  gap: 20px;
}

.footer-links a {
  color: var(--text-dim);
}

.footer-links a:hover { color: var(--accent); }

/* ========== Reveal animation ========== */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
  .dot { animation: none; }
}

/* ========== Responsive ========== */
@media (max-width: 640px) {
  .section { padding: 64px 0; }
  .hero-meta { flex-direction: column; gap: 8px; align-items: flex-start; }
  .education-card { flex-direction: column; }
  .footer-inner { flex-direction: column; text-align: center; }
}