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

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #111118;
  --bg-card: #16161f;
  --bg-card-hover: #1c1c28;
  --border: #252536;
  --text-primary: #e8e8ed;
  --text-secondary: #9898b0;
  --text-muted: #686880;
  --accent: #6366f1;
  --accent2: #8b5cf6;
  --accent3: #06b6d4;
  --accent4: #f59e0b;
  --green: #22c55e;
  --red: #ef4444;
  --radius: 12px;
  --radius-lg: 16px;
  --font: 'Inter', 'Noto Sans SC', -apple-system, sans-serif;
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  font-family: var(--font);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

/* === Navigation === */
#nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(10,10,15,0.85); backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: transform 0.3s;
}
#nav.hidden { transform: translateY(-100%); }

.nav-inner {
  max-width: 1200px; margin: 0 auto; padding: 0 24px;
  height: 64px; display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  font-size: 24px; font-weight: 800; letter-spacing: -1px;
}
.nav-logo .accent { color: var(--accent); }
.nav-links { display: flex; gap: 32px; }
.nav-links a {
  font-size: 14px; font-weight: 500; color: var(--text-secondary);
  transition: color 0.2s; position: relative;
}
.nav-links a:hover, .nav-links a.active { color: var(--text-primary); }
.nav-links a.active::after {
  content: ''; position: absolute; bottom: -4px; left: 0; right: 0;
  height: 2px; background: var(--accent); border-radius: 1px;
}

.nav-toggle { display: none; background: none; border: none; cursor: pointer; flex-direction: column; gap: 5px; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--text-primary); border-radius: 1px; transition: 0.3s; }

/* === Hero === */
#hero {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  position: relative; overflow: hidden; padding: 100px 24px;
}
.hero-bg {
  position: absolute; inset: 0;
  background: radial-gradient(80% 60% at 50% 30%, rgba(99,102,241,0.12), transparent 70%),
              radial-gradient(60% 50% at 80% 70%, rgba(139,92,246,0.08), transparent 70%),
              radial-gradient(50% 40% at 20% 60%, rgba(6,182,212,0.06), transparent 70%);
}
.hero-content { position: relative; z-index: 1; text-align: center; max-width: 720px; }
.hero-greeting { font-size: 14px; color: var(--accent); text-transform: uppercase; letter-spacing: 4px; margin-bottom: 16px; }
.hero-title { font-size: 56px; font-weight: 800; line-height: 1.15; margin-bottom: 24px; letter-spacing: -1.5px; }
.gradient-text {
  background: linear-gradient(135deg, var(--accent), var(--accent2), var(--accent3));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.hero-desc { font-size: 18px; color: var(--text-secondary); line-height: 1.8; margin-bottom: 40px; }

.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.btn-primary, .btn-secondary {
  display: inline-flex; align-items: center; padding: 14px 28px; border-radius: 8px;
  font-size: 15px; font-weight: 600; transition: all 0.25s; cursor: pointer;
}
.btn-primary { background: var(--accent); color: #fff; box-shadow: 0 4px 20px rgba(99,102,241,0.3); }
.btn-primary:hover { background: #7577f5; transform: translateY(-1px); box-shadow: 0 6px 28px rgba(99,102,241,0.4); }
.btn-secondary {
  background: transparent; color: var(--text-primary); border: 1.5px solid var(--border);
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

.scroll-hint {
  position: absolute; bottom: 40px; left: 50%; transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 8px; animation: bounce 2s infinite;
}
.scroll-hint span {
  width: 24px; height: 40px; border: 2px solid var(--text-muted); border-radius: 12px; position: relative;
}
.scroll-hint span::after {
  content: ''; position: absolute; top: 8px; left: 50%; transform: translateX(-50%);
  width: 4px; height: 8px; background: var(--text-muted); border-radius: 2px; animation: scroll-dot 2s infinite;
}
@keyframes bounce { 0%,100%{transform:translateX(-50%) translateY(0)} 50%{transform:translateX(-50%) translateY(8px)} }
@keyframes scroll-dot { 0%,100%{opacity:1;top:8px} 50%{opacity:0;top:20px} }

/* === Section Common === */
section { padding: 100px 24px; }
.section-header { text-align: center; margin-bottom: 64px; }
.section-tag {
  display: inline-block; font-size: 12px; font-weight: 600; color: var(--accent);
  text-transform: uppercase; letter-spacing: 3px; margin-bottom: 12px;
  padding: 4px 12px; background: rgba(99,102,241,0.1); border-radius: 100px;
}
.section-header h2 { font-size: 36px; font-weight: 700; letter-spacing: -0.5px; margin-bottom: 8px; }
.section-header p { color: var(--text-secondary); font-size: 16px; max-width: 560px; margin: 0 auto; }

/* === ECS Architecture === */
#ecs { background: var(--bg-secondary); }

.ecs-arch { max-width: 1000px; margin: 0 auto 72px; }
.ecs-arch h3, .ecs-dataflow h3, .ecs-platforms h3 {
  text-align: center; font-size: 20px; margin-bottom: 32px; color: var(--text-secondary);
}

.arch-diagram {
  display: grid; grid-template-columns: 1fr auto 1fr; grid-template-rows: auto auto;
  gap: 20px; align-items: center; justify-items: center; position: relative;
}

.arch-node {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 28px 24px; text-align: center; transition: transform 0.3s, border-color 0.3s;
  min-width: 240px; max-width: 320px;
}
.arch-node:hover { transform: translateY(-4px); }
.arch-desktop:hover { border-color: var(--accent); }
.arch-hub:hover { border-color: var(--accent2); }
.arch-mobile:hover { border-color: var(--accent3); }

.arch-icon { font-size: 40px; margin-bottom: 12px; }
.arch-label { font-size: 18px; font-weight: 600; margin-bottom: 4px; }
.arch-tech { font-size: 13px; color: var(--text-muted); margin-bottom: 14px; }
.arch-features { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; }
.arch-features span {
  font-size: 12px; padding: 3px 10px; background: rgba(99,102,241,0.08);
  border-radius: 100px; color: var(--text-secondary);
}

.arch-hub {
  grid-column: 1 / -1; justify-self: center;
  background: linear-gradient(135deg, rgba(139,92,246,0.08), rgba(99,102,241,0.06));
  border-color: rgba(139,92,246,0.2);
}
.arch-hub .arch-features span { background: rgba(139,92,246,0.1); }

.arch-lines { display: none; } /* SVG overlay only needed on larger screens */

/* === ECS Features === */
.ecs-features {
  max-width: 1100px; margin: 0 auto 72px;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px;
}

.feature-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; transition: all 0.3s;
}
.feature-card:hover {
  border-color: rgba(99,102,241,0.3); transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.3);
}
.fc-icon { font-size: 32px; margin-bottom: 16px; }
.feature-card h4 { font-size: 17px; font-weight: 600; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* === Data Flow === */
.ecs-dataflow { max-width: 1000px; margin: 0 auto 72px; }

.dataflow-timeline {
  display: flex; align-items: flex-start; justify-content: center; flex-wrap: wrap;
  gap: 16px;
}
.df-step {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 24px 20px; text-align: center; flex: 1; min-width: 180px; max-width: 220px;
}
.df-num {
  width: 36px; height: 36px; border-radius: 50%; background: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 16px; color: #fff; margin: 0 auto 12px;
}
.df-step h4 { font-size: 15px; font-weight: 600; margin-bottom: 6px; }
.df-step p { font-size: 13px; color: var(--text-muted); line-height: 1.5; }
.df-arrow {
  font-size: 24px; color: var(--accent2); font-weight: 300;
  display: flex; align-items: center; padding-top: 24px;
}

/* === Platforms === */
.ecs-platforms { max-width: 800px; margin: 0 auto; }

.platform-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.platform-item {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 24px 16px; text-align: center; transition: all 0.3s;
  display: flex; flex-direction: column; align-items: center; gap: 8px;
}
.platform-item:hover { border-color: var(--green); }
.pl-icon { font-size: 32px; }
.platform-item span { font-size: 15px; font-weight: 600; }
.platform-item small { font-size: 12px; color: var(--text-muted); }

/* === Projects === */
#projects { background: var(--bg-primary); }

.project-cards { max-width: 1100px; margin: 0 auto; display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 20px; }

.pc-header { margin-bottom: 12px; }
.pc-tag { font-size: 11px; color: var(--text-muted); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 6px; }
.pc-header h3 { font-size: 20px; font-weight: 700; display: inline; }
.pc-badge {
  display: inline-block; font-size: 11px; font-weight: 600; padding: 2px 10px;
  border-radius: 100px; margin-left: 8px; vertical-align: middle;
  background: rgba(99,102,241,0.15); color: var(--accent);
}
.pc-badge.old { background: rgba(104,104,128,0.15); color: var(--text-muted); }
.pc-badge.store { background: rgba(6,182,212,0.15); color: var(--accent3); }

.project-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; margin-bottom: 16px; }

.pc-stack { display: flex; flex-wrap: wrap; gap: 8px; }
.pc-stack span {
  font-size: 12px; padding: 4px 12px; background: rgba(255,255,255,0.04);
  border: 1px solid var(--border); border-radius: 6px; color: var(--text-secondary);
}

/* === Tech Stack === */
#tech { background: var(--bg-secondary); }

.tech-grid { max-width: 1000px; margin: 0 auto; display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 24px; }

.tech-group { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; }
.tech-group h4 { font-size: 15px; font-weight: 600; margin-bottom: 14px; color: var(--accent); }
.tech-items { display: flex; flex-wrap: wrap; gap: 8px; }
.tech-items span {
  font-size: 13px; padding: 5px 12px; background: rgba(255,255,255,0.03);
  border: 1px solid var(--border); border-radius: 6px; color: var(--text-secondary);
}

/* === About === */
#about { background: var(--bg-primary); }
.about-content {
  max-width: 800px; margin: 0 auto; display: grid; grid-template-columns: 1fr 280px; gap: 48px; align-items: center;
}
.about-text p { color: var(--text-secondary); font-size: 15px; line-height: 1.8; margin-bottom: 16px; }
.about-links { margin-top: 24px; }
.about-link {
  display: inline-flex; align-items: center; gap: 8px; padding: 10px 20px;
  border: 1px solid var(--border); border-radius: 8px; font-size: 14px; font-weight: 500;
  transition: all 0.25s;
}
.about-link:hover { border-color: var(--accent); color: var(--accent); }

.about-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.stat { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; text-align: center; }
.stat strong {
  display: block; font-size: 32px; font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.stat span { font-size: 13px; color: var(--text-muted); margin-top: 4px; display: block; }

/* === Contact CTA === */
#contact { background: var(--bg-secondary); }
.contact-cta {
  max-width: 600px; margin: 0 auto; text-align: center; padding: 60px 24px;
}
.contact-cta h2 { font-size: 36px; font-weight: 700; margin-bottom: 12px; letter-spacing: -0.5px; }
.contact-cta p { color: var(--text-secondary); font-size: 16px; margin-bottom: 32px; }
.contact-links { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.contact-link {
  display: inline-flex; align-items: center; gap: 10px; padding: 14px 28px;
  border: 1px solid var(--border); border-radius: 8px; font-size: 15px; font-weight: 500;
  transition: all 0.25s; color: var(--text-secondary);
}
.contact-link:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-1px); }
.contact-link svg { flex-shrink: 0; }

/* === Footer Enhanced === */
.footer-inner {
  max-width: 1200px; margin: 0 auto; padding: 40px 24px 24px;
  display: flex; justify-content: space-between; align-items: flex-start;
  flex-wrap: wrap; gap: 32px;
}
.footer-brand .footer-logo { font-size: 20px; font-weight: 800; letter-spacing: -1px; }
.footer-brand .footer-logo .accent { color: var(--accent); }
.footer-brand p { font-size: 13px; color: var(--text-muted); margin-top: 8px; }
.footer-links { display: flex; gap: 24px; }
.footer-links a { font-size: 13px; color: var(--text-secondary); transition: color 0.2s; }
.footer-links a:hover { color: var(--accent); }
.footer-bottom { border-top: 1px solid var(--border); padding: 16px 24px; text-align: center; }
.footer-bottom p { color: var(--text-muted); font-size: 12px; }

/* === Project Card === */
.project-card {
  display: block; color: inherit; text-decoration: none;
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 28px; transition: all 0.3s;
}
.project-card:hover { border-color: rgba(99,102,241,0.2); transform: translateY(-2px); }
.project-card.featured { border-color: rgba(99,102,241,0.3); background: linear-gradient(135deg, rgba(99,102,241,0.04), transparent); }
.project-card.featured:hover { border-color: var(--accent); }
.pc-links { display: flex; gap: 12px; margin-top: 12px; }
.pc-links a { font-size: 13px; color: var(--accent); text-decoration: none; font-weight: 500; }
.pc-links a:hover { text-decoration: underline; }

/* === Responsive === */
@media (max-width: 900px) {
  .hero-title { font-size: 36px; }
  .hero-desc { font-size: 16px; }
  .nav-links { display: none; }
  .nav-toggle { display: flex; }
  .arch-diagram { grid-template-columns: 1fr; }
  .arch-lines { display: none; }
  .arch-hub { grid-column: auto; }
  .dataflow-timeline { flex-direction: column; align-items: center; }
  .df-arrow { transform: rotate(90deg); padding-top: 0; }
  .df-step { max-width: 100%; }
  .platform-grid { grid-template-columns: repeat(2, 1fr); }
  .about-content { grid-template-columns: 1fr; }
  .about-stats { grid-template-columns: repeat(4, 1fr); }
}

@media (max-width: 600px) {
  .hero-actions { flex-direction: column; align-items: center; }
  .section-header h2 { font-size: 28px; }
  .project-cards { grid-template-columns: 1fr; }
  .ecs-features { grid-template-columns: 1fr; }
  .platform-grid { grid-template-columns: 1fr 1fr; }
  .about-stats { grid-template-columns: 1fr 1fr; }
}

/* === Theme Toggle Button === */
.theme-toggle {
  background: none; border: 1.5px solid var(--border); border-radius: 8px;
  width: 40px; height: 40px; display: flex; align-items: center; justify-content: center;
  cursor: pointer; color: var(--text-secondary); transition: all 0.25s; position: relative;
  margin-left: 8px;
}
.theme-toggle:hover { border-color: var(--accent); color: var(--accent); }
.theme-toggle svg { width: 20px; height: 20px; position: absolute; transition: all 0.35s; }
.theme-toggle .theme-icon-dark { opacity: 1; transform: rotate(0deg) scale(1); }
.theme-toggle .theme-icon-light { opacity: 0; transform: rotate(90deg) scale(0.5); }
[data-theme="light"] .theme-toggle .theme-icon-dark { opacity: 0; transform: rotate(-90deg) scale(0.5); }
[data-theme="light"] .theme-toggle .theme-icon-light { opacity: 1; transform: rotate(0deg) scale(1); }

/* === Light Theme === */
[data-theme="light"] {
  --bg-primary: #f8f9fc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f0f1f5;
  --border: #e2e4ea;
  --text-primary: #1a1a2e;
  --text-secondary: #555770;
  --text-muted: #8e8ea0;
  --accent: #4f46e5;
  --accent2: #7c3aed;
  --accent3: #0891b2;
  --accent4: #d97706;
  --green: #16a34a;
  --red: #dc2626;
}
[data-theme="light"] #nav {
  background: rgba(255,255,255,0.88);
  border-bottom-color: var(--border);
}
[data-theme="light"] .hero-bg {
  background:
    radial-gradient(80% 60% at 50% 30%, rgba(79,70,229,0.08), transparent 70%),
    radial-gradient(60% 50% at 80% 70%, rgba(124,58,237,0.06), transparent 70%),
    radial-gradient(50% 40% at 20% 60%, rgba(8,145,178,0.05), transparent 70%);
}
[data-theme="light"] .gradient-text {
  -webkit-text-fill-color: unset;
  color: var(--accent);
  background: none;
}
[data-theme="light"] .scroll-hint span { border-color: var(--text-muted); }
[data-theme="light"] .scroll-hint span::after { background: var(--text-muted); }
[data-theme="light"] .feature-card { box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
[data-theme="light"] .project-card { box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
[data-theme="light"] .tech-group { box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
[data-theme="light"] .stat { box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
[data-theme="light"] .platform-item { box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
[data-theme="light"] .arch-node { box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
[data-theme="light"] .df-step { box-shadow: 0 1px 3px rgba(0,0,0,0.06); }

/* === Page Load Transition === */
.page-transition {
  animation: pageIn 0.5s ease-out both;
}
@keyframes pageIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}
@media (prefers-reduced-motion: reduce) {
  .page-transition { animation: none; }
  .scroll-hint { animation: none; }
  .fade-up { animation: none; opacity: 1; transform: none; }
  @keyframes bounce { from, to { transform: translateX(-50%) translateY(0); } }
  @keyframes scroll-dot { from, to { opacity: 1; top: 8px; } }
}

/* === Blog === */
#blog { background: var(--bg-primary); }

.blog-grid { max-width: 1100px; margin: 0 auto; display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px; }

.blog-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 28px; display: flex; flex-direction: column; transition: all 0.3s;
}
.blog-card:hover { border-color: rgba(99,102,241,0.25); transform: translateY(-3px); box-shadow: 0 8px 30px rgba(0,0,0,0.2); }

.bc-meta { display: flex; gap: 12px; align-items: center; margin-bottom: 12px; font-size: 12px; }
.bc-date { color: var(--text-muted); }
.bc-tag { padding: 2px 10px; background: rgba(99,102,241,0.1); color: var(--accent); border-radius: 100px; font-weight: 500; }

.bc-title { font-size: 17px; font-weight: 700; margin-bottom: 10px; line-height: 1.5; }
.bc-excerpt { font-size: 13.5px; color: var(--text-secondary); line-height: 1.7; flex: 1; margin-bottom: 16px; }
.bc-read { font-size: 13px; color: var(--accent); font-weight: 500; }

@media (max-width: 600px) {
  .blog-grid { grid-template-columns: 1fr; }
}

/* === Smooth theme transition === */
body { transition: background-color 0.35s ease, color 0.35s ease; }
section { transition: background-color 0.35s ease; }
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}
.fade-up { animation: fadeUp 0.6s ease-out both; }

/* === Legal / Privacy === */
.page-hero {
  text-align: center; padding: 60px 24px 40px;
}
.page-hero h1 { font-size: 36px; font-weight: 800; margin-bottom: 8px; }
.page-hero .subtitle { color: var(--text-muted); font-size: 14px; }

.legal-content {
  max-width: 760px; margin: 0 auto; padding: 0 24px 80px;
}
.legal-content section {
  margin-bottom: 40px;
}
.legal-content h2 {
  font-size: 22px; font-weight: 700; margin-bottom: 16px; padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
.legal-content h3 {
  font-size: 16px; font-weight: 600; margin: 24px 0 10px; color: var(--text-primary);
}
.legal-content p {
  font-size: 14.5px; color: var(--text-secondary); line-height: 1.85; margin-bottom: 12px;
}
.legal-content ul {
  padding-left: 20px; margin-bottom: 16px;
}
.legal-content li {
  font-size: 14px; color: var(--text-secondary); line-height: 1.8; margin-bottom: 6px;
}
.legal-content strong { color: var(--text-primary); }
.legal-content code {
  font-size: 13px; background: var(--bg-card); padding: 2px 6px; border-radius: 4px;
  border: 1px solid var(--border);
}
.legal-content a { color: var(--accent); text-decoration: underline; }
.legal-content table {
  width: 100%; border-collapse: collapse; margin: 16px 0;
  font-size: 14px;
}
.legal-content th {
  text-align: left; padding: 10px 12px; background: var(--bg-card);
  border-bottom: 2px solid var(--border); font-weight: 600; color: var(--text-primary);
}
.legal-content td {
  padding: 10px 12px; border-bottom: 1px solid var(--border); color: var(--text-secondary);
}

/* Mobile Nav */
.nav-open .nav-links {
  display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0;
  background: var(--bg-secondary); border-bottom: 1px solid var(--border); padding: 16px 24px; gap: 16px;
}