/* ===== Design tokens ===== */
:root {
  --bg: #ffffff;
  --bg-soft: #f5f6f8;
  --surface: #ffffff;
  --border: #e6e8ec;
  --text: #1a1d24;
  --text-soft: #5b6270;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --shadow: 0 6px 24px rgba(20, 24, 40, 0.08);
  --radius: 14px;
  --maxw: 1080px;
}

[data-theme="dark"] {
  --bg: #0d1017;
  --bg-soft: #141823;
  --surface: #161b26;
  --border: #232a39;
  --text: #e8ebf2;
  --text-soft: #9aa3b4;
  --accent: #818cf8;
  --accent-hover: #a5b4fc;
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.4);
}

/* ===== Reset / base ===== */
* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background 0.3s ease, color 0.3s ease;
}

a { color: inherit; text-decoration: none; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 1.25rem; }

/* ===== Header / nav ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand { font-weight: 800; font-size: 1.4rem; letter-spacing: -0.02em; }
.brand span { color: var(--accent); }

.nav-links {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.nav-links a { color: var(--text-soft); font-weight: 500; transition: color 0.2s; }
.nav-links a:hover { color: var(--text); }

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.15rem;
  line-height: 1;
}

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

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 0.7rem 1.4rem;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.2s ease, border-color 0.2s ease;
  border: 1px solid transparent;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-hover); }
.btn-ghost { background: transparent; border-color: var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* ===== Hero ===== */
.hero { padding: 6rem 1.25rem 4rem; text-align: center; }
.eyebrow { color: var(--accent); font-weight: 600; letter-spacing: 0.05em; text-transform: uppercase; font-size: 0.85rem; }
.hero-title { font-size: clamp(2.5rem, 6vw, 4rem); font-weight: 800; letter-spacing: -0.03em; margin: 0.5rem 0; }
.hero-subtitle { font-size: clamp(1.1rem, 2.5vw, 1.5rem); color: var(--text); font-weight: 600; }
.hero-text { max-width: 560px; margin: 1.25rem auto 0; color: var(--text-soft); }
.hero-actions { display: flex; gap: 1rem; justify-content: center; margin-top: 2rem; flex-wrap: wrap; }

/* ===== Sections ===== */
.section { padding: 4rem 1.25rem; }
.section-head { text-align: center; margin-bottom: 2.5rem; }
.section-head h2 { font-size: clamp(1.8rem, 4vw, 2.5rem); font-weight: 800; letter-spacing: -0.02em; }
.section-head p { color: var(--text-soft); margin-top: 0.5rem; }

/* ===== Filters ===== */
.filters { display: flex; gap: 0.5rem; justify-content: center; flex-wrap: wrap; margin-bottom: 2rem; }
.filter {
  padding: 0.45rem 1.1rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-soft);
  cursor: pointer;
  font-weight: 500;
  font-size: 0.9rem;
  transition: 0.2s;
}
.filter:hover { color: var(--text); border-color: var(--accent); }
.filter.active { background: var(--accent); color: #fff; border-color: var(--accent); }

/* ===== Projects grid ===== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--accent); }

.card-thumb {
  height: 170px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  background: linear-gradient(135deg, var(--accent) 0%, color-mix(in srgb, var(--accent) 50%, #000) 100%);
  color: #fff;
  overflow: hidden;
}
.card-thumb.has-img { background: var(--bg-soft); padding: 0; }
.card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
}

.card-body { padding: 1.25rem; display: flex; flex-direction: column; flex: 1; }
.card-body h3 { font-size: 1.15rem; font-weight: 700; }
.card-body p { color: var(--text-soft); font-size: 0.92rem; margin: 0.5rem 0 1rem; flex: 1; }

.tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-bottom: 1rem; }
.tag {
  font-size: 0.72rem;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: var(--bg-soft);
  color: var(--text-soft);
  font-weight: 500;
}

.card-links { display: flex; gap: 1rem; }
.card-links a { font-size: 0.88rem; font-weight: 600; color: var(--accent); }
.card-links a:hover { text-decoration: underline; }

/* ===== About ===== */
.about-grid { display: grid; grid-template-columns: 1.5fr 1fr; gap: 2.5rem; align-items: start; }
.about-text p { color: var(--text-soft); margin-bottom: 1rem; }
.skills h3 { margin-bottom: 1rem; }
.skill-tags { list-style: none; display: flex; flex-wrap: wrap; gap: 0.5rem; }
.skill-tags li {
  padding: 0.4rem 0.85rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 500;
}

/* ===== Contact ===== */
.contact-links { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

/* ===== Footer ===== */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
  color: var(--text-soft);
  font-size: 0.9rem;
}

/* ===== Responsive ===== */
@media (max-width: 720px) {
  .nav-toggle { display: flex; }
  .nav-links {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 1rem 1.25rem;
    gap: 1rem;
    transform: translateY(-150%);
    transition: transform 0.3s ease;
  }
  .nav-links.open { transform: translateY(0); }
  .about-grid { grid-template-columns: 1fr; }
}