/* ===== Flip7 Design Tokens ===== */
:root {
  --primary: #2BA8A2;
  --primary-light: #3CC4BD;
  --primary-dark: #1E8C86;
  --primary-bg: #E8F6F5;

  --gold: #FFD23F;
  --gold-light: #FFE47A;
  --gold-dark: #E6B800;

  --coral: #EF6C4A;
  --coral-light: #FF8A6A;
  --coral-dark: #D45233;

  --cream: #FFF8E7;
  --sky: #5DADE2;

  --surface: #EFF8F7;
  --card: #FFFFFF;

  --success: #27AE60;
  --error: #E74C3C;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-round: 999px;

  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;

  --font-stack: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

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

body {
  font-family: var(--font-stack);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: linear-gradient(145deg, #1a2a3a 0%, #0d1a2a 100%);
  color: var(--primary-dark);
  padding: 20px;
}

/* ===== Container ===== */
.container {
  width: 380px;
  background: var(--surface);
  border-radius: var(--radius-xl);
  padding: 20px 20px 24px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.2);
  position: relative;
}

/* ===== Logo Section ===== */
.logo-section {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 16px;
  padding-top: 8px;
}

.fan-cards {
  position: absolute;
  top: -4px;
  left: 50%;
  transform: translateX(-50%);
  width: 180px;
  height: 64px;
  z-index: 0;
}

.fan-card {
  position: absolute;
  width: 44px;
  height: 60px;
  border-radius: 6px;
  border: 2px solid rgba(0,0,0,0.1);
  left: 50%;
  bottom: 0;
  transform-origin: bottom center;
  transform: translateX(-50%) rotate(calc(var(--i) * 12deg - 24deg));
  background: var(--c);
  box-shadow: 0 2px 6px rgba(0,0,0,0.12);
  z-index: 1;
}

.fan-card:nth-child(1) { background: var(--coral); }
.fan-card:nth-child(2) { background: var(--sky); }
.fan-card:nth-child(3) { background: var(--primary); }
.fan-card:nth-child(4) { background: var(--gold); }
.fan-card:nth-child(5) { background: var(--primary-bg); }

.logo-text {
  position: relative;
  z-index: 2;
  display: inline-flex;
  align-items: baseline;
  transform: rotate(-3deg);
  background: var(--cream);
  padding: 2px 16px 2px 20px;
  border: 3px solid var(--primary-dark);
  border-radius: 4px;
  transform: rotate(-3deg) skewX(-6deg);
}

.logo-flip {
  font-family: var(--font-stack);
  font-size: 44px;
  font-weight: 800;
  letter-spacing: 4px;
  color: var(--primary-dark);
  text-shadow: 0 1px 2px rgba(0,0,0,0.15);
  display: inline-block;
  transform: skewX(6deg);
}

.logo-seven {
  font-family: var(--font-stack);
  font-size: 76px;
  font-weight: 800;
  color: var(--gold);
  transform: rotate(5deg) skewX(6deg);
  display: inline-block;
  line-height: 1;
  text-shadow:
    2px 0 0 var(--primary-dark),
    -1px 0 0 var(--primary-dark),
    0 2px 0 var(--primary-dark),
    0 -1px 0 var(--primary-dark),
    1px 1px 0 var(--primary-dark),
    -1px -1px 0 var(--primary-dark),
    1px -1px 0 var(--primary-dark),
    -1px 1px 0 var(--primary-dark),
    3px 3px 0 rgba(0,0,0,0.2);
}

/* ===== Ribbon Banner ===== */
.ribbon-banner {
  position: relative;
  z-index: 2;
  margin-top: -4px;
  display: flex;
  justify-content: center;
}

.ribbon-body {
  background: var(--cream);
  border: 3px solid var(--primary-dark);
  padding: 2px 24px;
  font-family: var(--font-stack);
  font-weight: 800;
  font-size: 12px;
  letter-spacing: 6px;
  color: var(--primary-dark);
  position: relative;
  z-index: 2;
  border-radius: 2px;
  text-transform: uppercase;
}

.ribbon-tail {
  position: absolute;
  top: 8px;
  width: 16px;
  height: 100%;
  background: #f0e8d0;
  border: 3px solid var(--primary-dark);
  border-top: none;
  z-index: 0;
}

.ribbon-tail-l {
  right: 100%;
  border-right: none;
  border-radius: 0 0 0 6px;
  transform-origin: top right;
  transform: skewY(6deg);
}

.ribbon-tail-r {
  left: 100%;
  border-left: none;
  border-radius: 0 0 6px 0;
  transform-origin: top left;
  transform: skewY(-6deg);
}

/* ===== Mode Tabs ===== */
.mode-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
}

.mode-tab {
  flex: 1;
  padding: 10px 0;
  border: none;
  border-radius: var(--radius-round);
  background: var(--card);
  color: var(--primary-dark);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
  box-shadow: 0 2px 6px rgba(0,0,0,0.06);
  letter-spacing: 1px;
}

.mode-tab:hover {
  background: var(--primary-bg);
  box-shadow: 0 2px 8px rgba(43,168,162,0.12);
}

.mode-tab.active {
  background: var(--primary);
  color: white;
  box-shadow: 0 4px 16px rgba(43,168,162,0.3);
}

/* ===== Calculator Body ===== */
.calc-body {
  animation: fadeSlideIn 0.3s ease-out;
}

@keyframes fadeSlideIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.hidden {
  display: none !important;
}

/* ===== Display ===== */
.display {
  background: var(--cream);
  border-radius: var(--radius-lg);
  padding: 16px 18px;
  margin-bottom: 12px;
  min-height: 80px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  align-items: flex-end;
  overflow: hidden;
  box-shadow: inset 0 2px 6px rgba(0,0,0,0.06);
}

.expression {
  font-size: 13px;
  font-weight: 500;
  color: #8a8a9a;
  min-height: 20px;
  word-break: break-all;
  text-align: right;
  width: 100%;
}

.result {
  font-size: 34px;
  font-weight: 800;
  color: var(--primary-dark);
  word-break: break-all;
  text-align: right;
  width: 100%;
  transition: font-size 0.1s;
}

/* ===== Buttons Grid ===== */
.buttons-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.sci-buttons-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
}

/* ===== Base Button ===== */
.btn {
  padding: 14px 0;
  border: none;
  border-radius: var(--radius-round);
  font-size: 18px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s cubic-bezier(0.34, 1.56, 0.64, 1);
  user-select: none;
  font-family: var(--font-stack);
  min-height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn:active {
  transform: scale(0.93);
}

/* ===== Number Button (Teal) ===== */
.btn-number {
  background: var(--primary);
  color: white;
  box-shadow: 0 4px 12px rgba(43,168,162,0.25);
}

.btn-number:hover {
  background: var(--primary-light);
  box-shadow: 0 4px 16px rgba(43,168,162,0.35);
}

/* ===== Zero Button (spans 2 cols) ===== */
.btn-zero {
  grid-column: span 2;
}

/* ===== Operator Button (Coral) ===== */
.btn-operator {
  background: var(--coral);
  color: white;
  box-shadow: 0 4px 12px rgba(239,108,74,0.25);
}

.btn-operator:hover {
  background: var(--coral-light);
  box-shadow: 0 4px 16px rgba(239,108,74,0.35);
}

/* ===== Clear Button (outlined coral) ===== */
.btn-clear {
  background: transparent;
  color: var(--coral);
  border: 2px solid var(--coral);
  box-shadow: none;
  font-weight: 800;
}

.btn-clear:hover {
  background: rgba(239,108,74,0.08);
  box-shadow: 0 4px 16px rgba(239,108,74,0.2);
}

/* ===== Primary Button (Gold CTA) ===== */
.btn-primary {
  background: linear-gradient(145deg, var(--gold), var(--gold-dark));
  color: var(--primary-dark);
  box-shadow: 0 4px 16px rgba(255,210,63,0.4);
  position: relative;
  overflow: hidden;
  font-size: 20px;
}

.btn-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(255,255,255,0.3) 0%, transparent 60%);
  border-radius: inherit;
  pointer-events: none;
}

.btn-primary:hover {
  box-shadow: 0 6px 24px rgba(255,210,63,0.5);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: scale(0.95);
}

/* ===== Scientific Button ===== */
.btn-sci {
  background: var(--card);
  color: var(--primary);
  border: 2px solid var(--primary-bg);
  font-size: 13px;
  font-weight: 700;
  min-height: 42px;
  padding: 10px 0;
  box-shadow: 0 2px 6px rgba(0,0,0,0.04);
}

.btn-sci:hover {
  background: var(--primary-bg);
  border-color: var(--primary);
  box-shadow: 0 2px 8px rgba(43,168,162,0.12);
}

/* ===== BOOM Pulse (applied to AC in BOOM state) ===== */
.btn-clear.boom-active {
  background: var(--coral);
  color: white;
  border-color: var(--coral);
  animation: boomPulse 2s infinite;
  box-shadow: 0 4px 20px rgba(239,108,74,0.35);
}

@keyframes boomPulse {
  0%, 100% { box-shadow: 0 4px 12px rgba(239,108,74,0.25); }
  50%      { box-shadow: 0 4px 28px rgba(239,108,74,0.5); transform: scale(1.02); }
}

/* ===== BMI Mode ===== */
.bmi-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.bmi-display .expression {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 15px;
  color: var(--primary-dark);
  font-weight: 700;
}

/* BMI Card (with left accent bar) */
.bmi-card {
  background: var(--card);
  border-radius: var(--radius-lg);
  box-shadow: 0 4px 20px rgba(43,168,162,0.1);
  display: flex;
  overflow: hidden;
  transition: all 0.3s ease;
}

.bmi-card-accent {
  width: 6px;
  min-height: 100%;
  background: var(--primary-light);
  flex-shrink: 0;
}

.bmi-card-accent.gold {
  background: linear-gradient(180deg, var(--gold), var(--gold-dark));
}

.bmi-card-content {
  flex: 1;
  padding: 16px;
}

.bmi-card.highlighted {
  box-shadow: 0 4px 20px rgba(255,210,63,0.3);
}

/* BMI Inputs */
.input-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 10px;
}

.input-group label {
  font-size: 13px;
  font-weight: 700;
  color: var(--primary-dark);
}

.input-group input {
  padding: 12px 14px;
  border: 2px solid var(--primary-bg);
  border-radius: var(--radius-md);
  background: var(--cream);
  color: var(--primary-dark);
  font-size: 16px;
  font-weight: 600;
  outline: none;
  transition: border-color 0.2s;
  font-family: var(--font-stack);
}

.input-group input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(43,168,162,0.15);
}

.input-group input::placeholder {
  color: #b0b0c0;
  font-weight: 400;
}

.bmi-calc-btn {
  width: 100%;
  padding: 14px !important;
  font-size: 15px !important;
  letter-spacing: 2px;
  margin-top: 2px;
}

/* BMI Result */
.bmi-result-content {
  text-align: center;
  padding: 20px;
}

.bmi-value {
  font-size: 42px;
  font-weight: 800;
  color: var(--coral);
  line-height: 1.1;
}

.bmi-category {
  font-size: 16px;
  font-weight: 700;
  margin-top: 4px;
}

.bmi-bar-track {
  height: 10px;
  background: #e8e8f0;
  border-radius: var(--radius-round);
  margin-top: 14px;
  overflow: hidden;
}

.bmi-bar-fill {
  height: 100%;
  width: 0%;
  border-radius: var(--radius-round);
  background: linear-gradient(90deg, #4caf50, var(--gold), var(--coral), var(--error));
  transition: width 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.bmi-labels {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  font-weight: 600;
  color: #8a8a9a;
  margin-top: 4px;
}

/* ===== Confetti ===== */
#confetti-container {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9999;
  overflow: hidden;
}

.confetti-piece {
  position: absolute;
  top: -20px;
  width: 10px;
  height: 10px;
  opacity: 0.9;
  animation: confettiFall linear forwards;
}

@keyframes confettiFall {
  0%   { transform: translateY(0) rotate(0deg); opacity: 1; }
  100% { transform: translateY(110vh) rotate(720deg); opacity: 0; }
}

/* ===== Glow Pulse (winner cards) ===== */
.glow-pulse {
  animation: glowPulse 2s infinite;
}

@keyframes glowPulse {
  0%, 100% { box-shadow: 0 4px 20px rgba(255,210,63,0.3); }
  50%      { box-shadow: 0 4px 32px rgba(255,210,63,0.55); transform: scale(1.01); }
}

/* ===== Crown Bounce ===== */
.crown-bounce {
  animation: crownBounce 1.5s infinite;
  display: inline-block;
}

@keyframes crownBounce {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  25%      { transform: translateY(-4px) rotate(-5deg); }
  50%      { transform: translateY(-2px) rotate(3deg); }
  75%      { transform: translateY(-5px) rotate(-2deg); }
}

/* ===== Responsive ===== */
@media (max-width: 420px) {
  .container { width: 100%; padding: 14px; }
  .logo-flip { font-size: 36px; }
  .logo-seven { font-size: 62px; }
  .btn { font-size: 16px; min-height: 46px; padding: 12px 0; }
  .display { min-height: 70px; padding: 12px 14px; }
  .result { font-size: 28px; }
}