/* CSS variables for theming */
:root {
  --bg-color: #f5f5f7;
  --bg-elevated: #ffffff;
  --text-color: #1f2933;
  --muted-text: #6b7280;
  --accent: #2563eb;
  --accent-soft: #dbeafe;
  --border-subtle: #e5e7eb;
  --shadow-soft: 0 10px 25px rgba(15, 23, 42, 0.08);
}

/* Dark theme overrides */
:root[data-theme="dark"] {
  --bg-color: #0b1120;
  --bg-elevated: #020617;
  --text-color: #e5e7eb;
  --muted-text: #9ca3af;
  --accent: #60a5fa;
  --accent-soft: #1d283a;
  --border-subtle: #1f2937;
  --shadow-soft: 0 16px 40px rgba(0, 0, 0, 0.7);
}

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

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  min-height: 100vh;
}

/* Layout */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 5vw;
  border-bottom: 1px solid var(--border-subtle);
  background: radial-gradient(circle at top left, var(--accent-soft), transparent),
              var(--bg-elevated);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
}

.header-left h1 {
  margin: 0;
  font-size: 1.6rem;
  letter-spacing: 0.06em;
}

.header-left p {
  margin: 0.25rem 0 0;
  font-size: 0.9rem;
  color: var(--muted-text);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

#theme-toggle {
  border: 1px solid var(--border-subtle);
  background-color: transparent;
  color: var(--text-color);
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
  font-size: 0.85rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  transition:
    background-color 0.2s ease,
    color 0.2s ease,
    border-color 0.2s ease,
    transform 0.1s ease,
    box-shadow 0.2s ease;
}

#theme-toggle:hover {
  background-color: var(--accent-soft);
  border-color: var(--accent);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

#theme-toggle:active {
  transform: translateY(1px) scale(0.98);
  box-shadow: none;
}

.notes-main {
  padding: 1.5rem 5vw 2.5rem;
}

/* Responsive grid for notes */
.notes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}

/* Card styling */
.note-box {
  background-color: var(--bg-elevated);
  border-radius: 0.9rem;
  padding: 1.1rem 1.15rem;
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-soft);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition:
    transform 0.15s ease,
    box-shadow 0.15s ease,
    border-color 0.15s ease,
    background-color 0.15s ease;
}

.note-box:hover {
  transform: translateY(-3px);
  box-shadow: 0 16px 35px rgba(15, 23, 42, 0.16);
  border-color: var(--accent);
}

.note-box h2 {
  margin: 0 0 0.4rem;
  font-size: 1rem;
}

.note-box p {
  margin: 0.15rem 0 0;
  font-size: 0.9rem;
  line-height: 1.4;
  color: var(--muted-text);
}

/* Links */

.note-box a {
  color: var(--accent);
  text-decoration: none;
  position: relative;
}

.note-box a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.15rem;
  width: 0;
  height: 2px;
  background-color: var(--accent);
  transition: width 0.2s ease;
}

.note-box a:hover::after {
  width: 100%;
}

/* Responsive tweaks */

@media (max-width: 768px) {
  .site-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
    padding-inline: 1.25rem;
  }

  .notes-main {
    padding-inline: 1.25rem;
  }
}

@media (max-width: 480px) {
  .header-left h1 {
    font-size: 1.3rem;
  }

  #theme-toggle {
    font-size: 0.8rem;
  }
}