@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&family=Poppins:wght@600;700&display=swap');

:root {
  --bg:#f7f8fa;
  --fg:#222;
  --muted:#6b7280;
  --card:#ffffff;
  --primary:#2563eb;
  --primary-hover:#1d4ed8;
  --nav:#0f172a;
  --nav-btn:#334155;
  --success:#16a34a;
  --warning:#d97706;
}

* { box-sizing: border-box; }

body {
  margin:0;
  font-family: 'Inter', sans-serif;
  color:var(--fg);
  background:var(--bg);
}

/* ------------------------
   Topbar
-------------------------*/
.topbar {
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:1rem;
  padding:0.75rem 1rem;
  background:var(--card);
  border-bottom:1px solid #e5e7eb;
  position:sticky; top:0; z-index:100;
}

.brand {
  display:flex;
  align-items:center;
  gap:0.6rem;
  flex-shrink:0;
}
.brand .logo { font-size:1.4rem; }
.topbar h1 {
  font-family:'Poppins',sans-serif;
  font-size:1.25rem;
  margin:0;
  white-space:nowrap;
}

.actions {
  display:flex;
  gap:0.5rem;
  flex-wrap:wrap;
}
.actions button { min-width: 90px; }

/* ------------------------
   Buttons
-------------------------*/
button {
  border:0;
  cursor:pointer;
  border-radius:10px;
  font-weight:600;
  padding:10px 14px;
  transition:transform .12s ease, background .2s ease;
  font-size:0.9rem;
}

button.primary { background:var(--primary); color:#fff; }
button.primary:hover { background:var(--primary-hover); transform:translateY(-1px); }

button.secondary { background:#e5e7eb; color:#111827; }
button.secondary:hover { background:#d1d5db; transform:translateY(-1px); }

button.danger { background:#dc2626; color:#fff; }
button.danger:hover { background:#b91c1c; transform:translateY(-1px); }

.inline.small { padding:4px 8px; border-radius:6px; }

/* Universal feature buttons */
.content-section button {
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 10px 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  font-size: 0.9rem;
}
.content-section button:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
}
.content-section button.danger {
  background: #dc2626;
}
.content-section button.danger:hover {
  background: #b91c1c;
}
.content-section button.secondary {
  background: #e5e7eb;
  color: #111827;
}
.content-section button.secondary:hover {
  background: #d1d5db;
}

/* ------------------------
   Status Row
-------------------------*/
.status-row {
  display:flex;
  gap:8px;
  align-items:center;
  justify-content:center;
  padding:8px;
  min-height:36px;
}
.badge {
  display:inline-flex;
  align-items:center;
  gap:6px;
  background:#fff3cd;
  color:#7a5d00;
  border:1px solid #ffe69c;
  padding:4px 10px;
  border-radius:999px;
  font-size:.875rem;
}
.badge.hidden { display:none; }

.toast {
  background:#ecfdf5;
  color:#065f46;
  border:1px solid #a7f3d0;
  padding:6px 12px;
  border-radius:10px;
  font-weight:600;
}
.toast.hidden { display:none; }

/* ------------------------
   Main Content
-------------------------*/
main { padding:24px 14px; max-width:1000px; margin:0 auto; }

.content-section {
  display:none;
  background:var(--card);
  border-radius:14px;
  padding:22px;
  box-shadow: 0 4px 10px rgba(0,0,0,.06);
}

/* Cards / grids */
.grid { display:grid; gap:14px; }
.grid.duo { grid-template-columns: repeat(2, minmax(0, 1fr)); }
@media (max-width: 820px){ .grid.duo{ grid-template-columns: 1fr; } }

.card {
  background:var(--bg);
  border:1px solid #e5e7eb;
  border-radius:12px;
  padding:14px;
}

/* Utility */
.muted { color:var(--muted); }
.live-clock { margin:1rem 0; font-size:1.125rem; font-weight:700; }
.row { display:flex; gap:10px; align-items:center; flex-wrap:wrap; }
.grow { flex:1 1 auto; min-width:180px; }
.result { font-weight:700; margin-top:8px; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace; }
.large { font-size:1.5rem; }
.callout {
  margin-top:16px;
  background:#eef2ff;
  color:#1e3a8a;
  border:1px solid #c7d2fe;
  padding:12px;
  border-radius:10px;
}

/* ------------------------
   Calculator
-------------------------*/
.calculator {
  max-width:320px;
  margin:auto;
  background:#f4f6fb;
  padding:18px;
  border-radius:16px;
}
#calcDisplay {
  width:100%;
  height:50px;
  font-size:1.5rem;
  text-align:right;
  margin-bottom:12px;
  border:1px solid #cbd5e1;
  border-radius:10px;
  padding:8px 10px;
  background:#fff;
}
.calc-grid { display:grid; grid-template-columns:repeat(4,1fr); gap:10px; }
.calc-grid button { background:#0f172a; color:#fff; border-radius:10px; padding:14px; }
.calc-grid button:hover { filter:brightness(1.1); }

/* ------------------------
   Notes / flashcards / planner / habits
-------------------------*/
#flashcardsContainer {
  display:grid;
  grid-template-columns:repeat(auto-fit, minmax(230px,1fr));
  gap:12px;
  margin-top:12px;
}
.flashcard {
  background:#ffffff;
  border:1px solid #e5e7eb;
  border-radius:12px;
  padding:12px;
}
#plannerContainer { margin-top:12px; text-align:left; }
.planner-entry {
  background:#f1f5f9;
  padding:12px;
  border-radius:10px;
  margin-bottom:10px;
  border:1px solid #e5e7eb;
}
#habitContainer { display:flex; flex-wrap:wrap; gap:10px; margin-top:10px; }
.habit {
  background:#f8fafc;
  border:1px solid #e5e7eb;
  border-radius:10px;
  padding:8px 12px;
  cursor:pointer;
}
.habit.done { background:#dcfce7; text-decoration:line-through; }

/* ------------------------
   Side menu (hamburger)
-------------------------*/
.side-menu {
  position: fixed;
  top: 0;
  left: -260px; /* hidden */
  width: 240px;
  height: 100vh;
  overflow-y: auto;
  background: var(--nav);
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  transition: left 0.3s ease;
  z-index: 200;
}
.side-menu.open { left: 0; }
.side-menu button {
  background: var(--nav-btn);
  color: #fff;
  padding: 12px;
  border-radius: 10px;
  text-align:left;
}
.side-menu button:hover { background: var(--primary-hover); }



/* ------------------------
   Responsive Fixes
-------------------------*/
@media (max-width: 600px) {
  .topbar {
    flex-wrap: wrap;
    align-items: center;
  }
  .brand {
    display:flex;
    align-items:center;
    gap:0.4rem;
  }
  .actions {
    width: 100%;
    justify-content: space-between;
    flex-wrap: wrap;
  }
}
  
/* ------------------------
   Dark mode
-------------------------*/
body.dark {
  --bg:#111827; --fg:#f9fafb; --card:#1f2937; --muted:#9ca3af;
  --nav:#1e293b; --nav-btn:#334155;
}
body.dark .card { background:#1e293b; border-color:#374151; }
body.dark .calculator { background:#1e2937; }