/*
  EMMANUEL INALEGWU
  VUG/SEN/22/7171
  SEN 482

  ============================================================
  INALEGWU EMMANUEL – SEN 482 Calculator styles
  ============================================================
*/

:root {
  --primary-color: #0d6efd;
  --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  --card-bg: rgba(255, 255, 255, 0.9);
  --btn-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
  --btn-hover-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
}

body {
  background: var(--bg-gradient);
  min-height: 100vh;
  display: flex;
  align-items: center;
  font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

/* ── Card ── */
.calculator-card {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 24px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
  overflow: hidden;
  transition: transform 0.3s ease;
}
.calculator-card:hover { transform: translateY(-5px); }

/* ── Display ── */
.display-container {
  background: #f8f9fa;
  padding: 20px;
  border-radius: 16px;
  margin-bottom: 16px;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.05);
  height: 90px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
}
#result {
  text-align: right;
  font-size: 38px;
  font-weight: 600;
  height: auto;
  border: none;
  background: transparent;
  padding: 0;
  color: #212529;
  box-shadow: none;
  width: 100%;
}

/* ── Roman numeral strip ── */
.word-display-area {
  background: rgba(255, 255, 255, 0.6);
  border-radius: 12px;
  padding: 10px 16px;
  border: 1px dashed rgba(13, 110, 253, 0.25);
  display: flex;
  align-items: center;
  gap: 12px;
  animation: slideUp 0.25s ease-out;
}
@keyframes slideUp {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}
.small-label {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #adb5bd;
  font-weight: 700;
}

/* ── Button grid ── */
.btn-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}
.calculator .btn {
  height: 60px;
  border-radius: 14px;
  font-size: 18px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  border: none;
  box-shadow: var(--btn-shadow);
}
.calculator .btn:hover  { transform: translateY(-2px); box-shadow: var(--btn-hover-shadow); }
.calculator .btn:active { transform: translateY(0); }

.btn-light    { background: #ffffff; color: #495057; }
.btn-light:hover { background: #f1f3f5; }

.btn-operator { background: #e7f1ff; color: var(--primary-color); }
.btn-operator:hover { background: #cfe2ff; }

.btn-action   { background: #fff5f5; color: #fa5252; }
.btn-action:hover { background: #ffe3e3; }

.btn-equals   { background: var(--primary-color); color: white; }
.btn-equals:hover { background: #0b5ed7; color: white; }

/* ── Header ── */
.group-header {
  color: #495057;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  font-size: 1.1rem;
}

/* ── Theme toggle ── */
.theme-toggle-btn {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 1000;
}

/* ── Dark mode ── */
body.dark-mode {
  background: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 100%);
  color: #e0e0e0;
}
body.dark-mode .calculator-card {
  background: rgba(45, 45, 45, 0.9);
  border-color: rgba(255, 255, 255, 0.1);
}
body.dark-mode .display-container { background: #333333; }
body.dark-mode #result            { color: #e0e0e0; }
body.dark-mode .btn-light         { background: #444444; color: #e0e0e0; }
body.dark-mode .btn-light:hover   { background: #555555; }