/* ============================================================
   ipaperVN Portfolio — style.css
   Phong cách: dark tech, gradient đen-tím, Quinquefive headings
   Gồm: loading, nav, hero (drag-to-orbit), stats, plugins,
   experience, blog, support/discord, và component styles
   dùng chung cho projects.html / tools.html.
   ============================================================ */

/* ---------- Design tokens ---------- */
:root {
  --bg-0: #0a0a0f;
  --bg-1: #14101f;
  --bg-2: #1c1530;
  --grad-end: #a855f7;
  --accent: #c084fc;
  --accent-deep: #7c3aed;
  --text: #f4f1fa;
  --text-dim: #9d94b8;
  --space-sm: 0.75rem;
  --space-md: 1.5rem;
  --space-lg: 3rem;
  --font-display: "Inter", system-ui, sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --nav-h: 68px;
  --radius: 12px;
  --border: 1px solid rgba(192, 132, 252, 0.18);
  --glow: 0 8px 30px rgba(168, 85, 247, 0.35);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 10px);
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-body);
  color: var(--text);
  background:
    linear-gradient(rgba(10, 10, 15, 0.85), rgba(14, 10, 24, 0.94)),
    url("../img/background.jpg") center / cover fixed no-repeat;
  background-color: var(--bg-0);
  line-height: 1.7;
  overflow-x: hidden;
}

img, svg { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
button { font-family: inherit; cursor: pointer; }

/* Heading chung — sans-serif đậm (phong cách hiện đại) */
.loader-brand, .nav-brand, .stat-num,
.plugin-title, .project-title, .skill-name, .tool-name,
.contact-heading, .discord-avatar { font-weight: 800; }

.container { width: 100%; max-width: 1120px; margin: 0 auto; padding: 0 var(--space-md); }

/* ============================================================
   LOADING SCREEN
   ============================================================ */
.loader {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: var(--bg-0);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity 0.6s ease, visibility 0.6s ease;
}
.loader.hide { opacity: 0; visibility: hidden; }
.loader-inner { text-align: center; width: min(320px, 80vw); }
.loader-brand {
  font-family: var(--font-display);
  font-size: 1.8rem;
  text-transform: uppercase;
  letter-spacing: 2px;
  background: linear-gradient(90deg, var(--grad-end), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: var(--space-md);
}
.loader-bar {
  height: 4px;
  background: var(--bg-2);
  border-radius: 4px;
  overflow: hidden;
}
.loader-bar span {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--accent-deep), var(--accent));
  border-radius: 4px;
  transition: width 0.15s linear;
}
.loader-pct {
  margin-top: var(--space-sm);
  font-size: 0.8rem;
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
}

/* ============================================================
   NAV
   ============================================================ */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10, 10, 15, 0.55);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: background 0.3s ease, border-color 0.3s ease;
}
.site-header.scrolled {
  background: rgba(10, 10, 15, 0.88);
  border-bottom-color: var(--border);
}
.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  height: var(--nav-h);
}
.nav-brand {
  font-family: var(--font-display);
  font-size: 1.05rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text);
}
.nav-brand:hover { color: var(--accent); }
.nav-links {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 1.1rem;
}
.nav-link {
  color: var(--text-dim);
  font-size: 0.9rem;
  font-weight: 500;
  white-space: nowrap;
  transition: color 0.2s ease;
}
.nav-link:hover, .nav-link.active { color: var(--accent); }

.lang-toggle {
  background: transparent;
  border: var(--border);
  border-radius: 6px;
  color: var(--text);
  padding: 0.4rem 0.9rem;
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 1px;
  transition: all 0.2s ease;
}
.lang-toggle:hover { border-color: var(--accent); color: var(--accent); box-shadow: 0 0 12px rgba(168, 85, 247, 0.4); }

.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: transparent;
  border: none;
  padding: 0 8px;
}
.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.3s ease;
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-top: calc(var(--nav-h) + 2rem);
}
.hero-inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  align-items: center;
}
.hero-name {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 9vw, 5rem);
  font-weight: 900;
  letter-spacing: -1px;
  line-height: 1.1;
}
.hero-name span {
  background: linear-gradient(90deg, var(--grad-end), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-role {
  margin-top: var(--space-sm);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text);
}
.hero-alias {
  margin-top: 0.6rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent);
}
.hero-status {
  margin-top: var(--space-sm);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-dim);
  font-size: 0.95rem;
}
.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #4ade80;
  box-shadow: 0 0 10px #4ade80;
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}
.hero-tagline {
  margin-top: var(--space-md);
  max-width: 560px;
  color: var(--text-dim);
  font-size: 1.05rem;
}
.hero-cta {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-lg);
  flex-wrap: wrap;
}
.hero-orbit-hint {
  margin-top: var(--space-md);
  color: var(--text-dim);
  font-size: 0.8rem;
  letter-spacing: 1px;
}

/* Orbit artwork (drag to rotate) */
.hero-art { display: flex; justify-content: center; }
.orbit {
  width: min(300px, 70vw);
  aspect-ratio: 1 / 1;
  perspective: 900px;
}
.orbit img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 24px;
  border: 1px solid var(--border);
  box-shadow: var(--glow);
  transform-style: preserve-3d;
  transition: transform 0.1s linear;
  user-select: none;
  -webkit-user-drag: none;
}

/* Hero stats */
.hero-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  margin-top: var(--space-lg);
}
.stat {
  text-align: center;
  padding: var(--space-md);
  background: rgba(20, 16, 31, 0.6);
  border: var(--border);
  border-radius: var(--radius);
}
.stat-num {
  font-family: var(--font-display);
  font-size: 2rem;
  color: var(--accent);
}
.stat-plus { color: var(--accent); font-weight: 700; }
.stat-label {
  display: block;
  margin-top: 0.3rem;
  color: var(--text-dim);
  font-size: 0.85rem;
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-block;
  padding: 0.85rem 1.8rem;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.95rem;
  min-height: 44px;
  transition: all 0.25s ease;
}
.btn-primary {
  background: linear-gradient(135deg, var(--grad-end), var(--accent-deep));
  color: #fff;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: var(--glow); }
.btn-ghost { border: var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* ============================================================
   SECTIONS (chung)
   ============================================================ */
.section { padding: 5rem 0; }
.section-alt { background: rgba(16, 12, 26, 0.5); border-block: var(--border); }
.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  font-weight: 800;
  letter-spacing: -0.5px;
  text-align: center;
  margin-bottom: var(--space-md);
}
.section-intro {
  text-align: center;
  color: var(--text-dim);
  max-width: 640px;
  margin: 0 auto var(--space-lg);
}

/* ============================================================
   PLUGINS
   ============================================================ */
.plugins-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}
.plugin-card {
  background: var(--bg-1);
  border: var(--border);
  border-radius: var(--radius);
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}
.plugin-card:hover {
  transform: translateY(-5px);
  border-color: var(--accent);
  box-shadow: var(--glow);
}
.plugin-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text);
}
.plugin-desc { color: var(--text-dim); font-size: 0.95rem; flex: 1; }
.plugin-tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.tag {
  background: rgba(124, 58, 237, 0.2);
  border: 1px solid rgba(124, 58, 237, 0.3);
  color: var(--accent);
  padding: 0.2rem 0.7rem;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
}
.card-link { align-self: flex-start; font-weight: 700; font-size: 0.9rem; color: var(--accent); }
.card-link:hover { text-decoration: underline; }
.plugins-more { text-align: center; margin-top: var(--space-lg); }

/* ============================================================
   EXPERIENCE / ABOUT
   ============================================================ */
.exp-body { max-width: 720px; margin: 0 auto; text-align: center; color: var(--text-dim); }
.exp-body p + p { margin-top: var(--space-sm); }
.exp-body strong { color: var(--text); }
.tech-icons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem;
  margin-top: var(--space-lg);
}
.tech {
  background: var(--bg-2);
  border: var(--border);
  color: var(--text);
  padding: 0.5rem 1rem;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  transition: all 0.2s ease;
}
.tech:hover { transform: translateY(-3px); border-color: var(--accent); color: var(--accent); box-shadow: var(--glow); }

/* ============================================================
   BLOG
   ============================================================ */
.blog-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}
.blog-card {
  background: var(--bg-1);
  border: var(--border);
  border-radius: var(--radius);
  padding: var(--space-md);
  transition: all 0.25s ease;
}
.blog-card:hover { transform: translateY(-5px); border-color: var(--accent); box-shadow: var(--glow); }
.blog-tag {
  display: inline-block;
  background: rgba(168, 85, 247, 0.15);
  color: var(--accent);
  border: var(--border);
  padding: 0.2rem 0.7rem;
  border-radius: 6px;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.blog-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
  margin: 0.8rem 0 0.4rem;
}
.blog-excerpt { color: var(--text-dim); font-size: 0.92rem; margin-bottom: var(--space-sm); }

/* ============================================================
   SUPPORT / CONTACT
   ============================================================ */
.support-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
  max-width: 720px;
  margin: 0 auto;
}
.discord-card {
  background: var(--bg-1);
  border: var(--border);
  border-radius: var(--radius);
  padding: var(--space-md);
}
.discord-head { display: flex; align-items: center; gap: 0.8rem; }
.discord-avatar {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--grad-end), var(--accent-deep));
  background-size: cover;
  background-position: center;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 0.8rem;
  color: #fff;
  flex-shrink: 0;
}
.discord-id { display: flex; flex-direction: column; }
.discord-name { font-weight: 700; color: var(--text); }
.discord-badge { font-size: 0.8rem; color: var(--text-dim); }
.discord-activity {
  margin-top: var(--space-md);
  background: var(--bg-2);
  border-radius: 8px;
  padding: 0.9rem;
  color: var(--text-dim);
  font-size: 0.9rem;
  min-height: 44px;
}
.discord-join { margin-top: var(--space-md); width: 100%; text-align: center; }

.contact-box {
  background: var(--bg-1);
  border: var(--border);
  border-radius: var(--radius);
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}
.contact-heading {
  font-family: var(--font-display);
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text);
  margin-bottom: 0.4rem;
}
.contact-link {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--text);
  font-weight: 600;
  min-height: 44px;
  transition: color 0.2s ease;
}
.contact-link:hover { color: var(--accent); }
.contact-icon { font-size: 1.2rem; }

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  border-top: var(--border);
  padding: 2rem 0;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.9rem;
}
.footer-note { margin-top: 0.3rem; font-size: 0.8rem; }

/* ============================================================
   BACK TO TOP
   ============================================================ */
.back-to-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: var(--border);
  background: var(--bg-1);
  color: var(--accent);
  font-size: 1.3rem;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.3s ease;
  z-index: 90;
}
.back-to-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: linear-gradient(135deg, var(--grad-end), var(--accent-deep)); color: #fff; box-shadow: var(--glow); }

/* ============================================================
   COMPONENT STYLES (projects.html / tools.html)
   ============================================================ */
.page-title { padding-top: calc(var(--nav-h) + 3rem); }

.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}
.project-card {
  background: var(--bg-1);
  border: var(--border);
  border-radius: var(--radius);
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}
.project-card:hover { transform: translateY(-5px); border-color: var(--accent); box-shadow: var(--glow); }
.project-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text);
}
.project-desc { color: var(--text-dim); font-size: 0.95rem; flex: 1; }

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: var(--space-lg);
}
.filter-btn {
  background: var(--bg-1);
  border: var(--border);
  color: var(--text-dim);
  padding: 0.45rem 1.1rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  min-height: 36px;
  transition: all 0.2s ease;
}
.filter-btn:hover { color: var(--accent); border-color: var(--accent); }
.filter-btn.active { background: linear-gradient(135deg, var(--grad-end), var(--accent-deep)); color: #fff; border-color: transparent; }

.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}
.skill-card {
  background: var(--bg-1);
  border: var(--border);
  border-radius: var(--radius);
  padding: var(--space-md);
  text-align: center;
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}
.skill-card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: var(--glow); }
.skill-icon { font-size: 2rem; margin-bottom: var(--space-sm); }
.skill-name {
  font-family: var(--font-display);
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--space-sm);
  color: var(--text);
}
.skill-desc { color: var(--text-dim); font-size: 0.92rem; }

.badge {
  background: rgba(168, 85, 247, 0.15);
  border: var(--border);
  color: var(--accent);
  padding: 0.4rem 1rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
}

.tools-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}
.tool-card {
  background: var(--bg-1);
  border: var(--border);
  border-radius: var(--radius);
  padding: var(--space-md);
}
.tool-name {
  font-family: var(--font-display);
  font-size: 1.05rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text);
  margin-bottom: var(--space-sm);
}
.tool-desc { color: var(--text-dim); font-size: 0.95rem; margin-bottom: var(--space-md); }
.tool-field {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-bottom: var(--space-sm);
  color: var(--text-dim);
  font-size: 0.9rem;
  font-weight: 500;
}
.tool-field input,
.tool-field select,
.tool-field textarea {
  background: var(--bg-0);
  border: var(--border);
  border-radius: 8px;
  color: var(--text);
  padding: 0.6rem 0.75rem;
  font-family: inherit;
  font-size: 0.95rem;
  width: 100%;
}
.tool-field input:focus,
.tool-field select:focus,
.tool-field textarea:focus { outline: none; border-color: var(--accent); }
.tool-field select option { background: var(--bg-1); color: var(--text); }
.tool-output {
  background: var(--bg-0);
  border: var(--border);
  border-radius: 8px;
  color: var(--accent);
  padding: 0.9rem;
  margin-top: var(--space-sm);
  font-size: 0.82rem;
  line-height: 1.5;
  white-space: pre-wrap;
  word-break: break-word;
  overflow-x: auto;
  min-height: 40px;
}
.tool-card .btn { margin-top: var(--space-sm); }

/* ============================================================
   SCROLL REVEAL
   ============================================================ */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 900px) {
  .hamburger { display: flex; }
  .nav-links {
    position: absolute;
    top: var(--nav-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(10, 10, 15, 0.98);
    border-bottom: var(--border);
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 0.4s ease, opacity 0.4s ease;
  }
  .nav-links.open { max-height: 100vh; opacity: 1; }
  .nav-links li { width: 100%; }
  .nav-link, .lang-toggle { display: block; padding: 0.9rem var(--space-md); font-size: 1.1rem; border-radius: 0; }
  .lang-toggle { border: none; text-align: left; }
}

@media (min-width: 768px) {
  .plugins-grid { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
  .blog-grid { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
  .projects-grid { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
  .skills-grid { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
  .tools-grid { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
  .hero-stats { grid-template-columns: repeat(4, 1fr); }
}

@media (min-width: 900px) {
  .hero-inner { grid-template-columns: 1.2fr 0.8fr; }
  .support-layout { grid-template-columns: 1.2fr 0.8fr; }
}

@media (max-width: 767px) {
  body { background-attachment: scroll; }
}

/* ============================================================
   REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .status-dot { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .back-to-top, .btn, .plugin-card, .project-card, .blog-card, .skill-card, .tech, .lang-toggle { transition: none; }
}