* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-bg-body: linear-gradient(135deg, #4c9f47 0%, #8dc291 100%);
  --color-text: #ffffff;
  --color-calculator-bg: #222222;
  --color-display-bg: #111111;
  --color-key-bg: #eeeeee;
  --color-key-hover-bg: #dddddd;
  --color-op-bg: #ff9500;
  --color-op-hover-bg: #e08b00;
  --color-func-bg: #d4d4d2;
  --color-func-hover-bg: #c3c3c1;
  --color-eq-bg: #4caf50;
  --color-eq-hover-bg: #45a049;
  --color-active-theme: #ffffff;
  --color-theme-button-border: #999999;
}

.theme-blue-yellow {
  --color-bg-body: linear-gradient(135deg, #2196f3 0%, #90caf9 100%);
  --color-calculator-bg: #ffffff;
  --color-display-bg: #e0e0e0;
  --color-text: #333333;
  --color-key-bg: #ffeb3b;
  --color-key-hover-bg: #fdd835;
  --color-op-bg: #42a5f5;
  --color-op-hover-bg: #2196f3;
  --color-func-bg: #bdbdbd;
  --color-func-hover-bg: #9e9e9e;
  --color-eq-bg: #607d8b;
  --color-eq-hover-bg: #455a64;
  --color-active-theme: #2196f3;
}

.theme-green-beige {
  --color-bg-body: linear-gradient(135deg, #8bc34a 0%, #cddc39 100%);
  --color-calculator-bg: #f5f5dc;
  --color-display-bg: #d7ccc8;
  --color-text: #3e2723;
  --color-key-bg: #a1887f;
  --color-key-hover-bg: #8d6e63;
  --color-op-bg: #4caf50;
  --color-op-hover-bg: #43a047;
  --color-func-bg: #bcaaa4;
  --color-func-hover-bg: #a1887f;
  --color-eq-bg: #6d4c41;
  --color-eq-hover-bg: #5d4037;
  --color-active-theme: #4caf50;
}

.theme-purple-pink {
  --color-bg-body: linear-gradient(135deg, #9c27b0 0%, #e91e63 100%);
  --color-calculator-bg: #ffffff;
  --color-display-bg: #f3e5f5;
  --color-text: #4a148c;
  --color-key-bg: #e1bee7;
  --color-key-hover-bg: #ce93d8;
  --color-op-bg: #8e24aa;
  --color-op-hover-bg: #6a1b9a;
  --color-func-bg: #d1c4e9;
  --color-func-hover-bg: #b39ddb;
  --color-eq-bg: #f48fb1;
  --color-eq-hover-bg: #f06292;
  --color-active-theme: #8e24aa;
}

.theme-joke {
  --color-bg-body: linear-gradient(135deg, #ff6f61 0%, #ffb3a7 100%);
  --color-calculator-bg: #400000;
  --color-display-bg: #800000;
  --color-text: #ffd700;
  --color-key-bg: #d4a600;
  --color-key-hover-bg: #b8860b;
  --color-op-bg: #ff4500;
  --color-op-hover-bg: #cc3700;
  --color-func-bg: #a9a9a9;
  --color-func-hover-bg: #808080;
  --color-eq-bg: #ffd700;
  --color-eq-hover-bg: #eedd82;
}

body {
  min-height: 100vh;
  font-family: Arial, sans-serif;
  background: var(--color-bg-body);
  color: var(--color-text);
  overflow: hidden;
  transition: background 0.3s ease;
}

.site-header {
  position: fixed;
  top: 20px;
  left: 50%;
  width: min(92%, 560px);
  transform: translateX(-50%);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 18px;
  z-index: 20;
  pointer-events: none;
}

.site-title,
.theme-switcher {
  pointer-events: auto;
}

.site-title {
  font-size: 2rem;
  line-height: 1;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
}

.theme-switcher {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  flex-wrap: wrap;
  gap: 10px;
}

.theme-button {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 2px solid var(--color-theme-button-border);
  cursor: pointer;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.theme-button:hover {
  transform: translateY(-2px);
}

.theme-button.active-theme {
  border-color: var(--color-active-theme);
  box-shadow: 0 0 0 4px var(--color-active-theme);
}

.theme-button--default {
  background: linear-gradient(135deg, #4c9f47 0%, #8dc291 100%);
}

.theme-button--blue-yellow {
  background: linear-gradient(135deg, #2196f3 0 50%, #ffeb3b 50% 100%);
}

.theme-button--green-beige {
  background: linear-gradient(135deg, #4caf50 0 50%, #f5f5dc 50% 100%);
}

.theme-button--purple-pink {
  background: linear-gradient(135deg, #8e24aa 0 50%, #f48fb1 50% 100%);
}

.joke-button {
  width: 46px;
  border-radius: 6px;
  font-size: 10px;
  font-weight: bold;
  color: #ffd700;
  background: #400000;
  border-color: #ff4500;
  display: flex;
  justify-content: center;
  align-items: center;
}

.calculator {
  position: absolute;
  width: 380px;
  max-width: calc(100vw - 28px);
  padding: 20px;
  border-radius: 15px;
  background: var(--color-calculator-bg);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
  transition: background 0.3s ease, box-shadow 0.2s ease;
  touch-action: none;
}

.calculator.is-movable {
  cursor: grab;
}

.calculator.is-dragging {
  cursor: grabbing;
}

.display {
  width: 100%;
  height: 60px;
  margin-bottom: 10px;
  padding: 10px;
  border: none;
  border-radius: 10px;
  background: var(--color-display-bg);
  color: var(--color-text);
  font-size: 2rem;
  line-height: 40px;
  text-align: right;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: background 0.3s ease;
}

.keys {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
}

.key {
  height: 60px;
  min-width: 0;
  border: none;
  border-radius: 10px;
  background: var(--color-key-bg);
  color: var(--color-text);
  font-size: 1.5rem;
  cursor: pointer;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  transition: background 0.3s ease, transform 0.1s ease;
}

.key:hover {
  background: var(--color-key-hover-bg);
}

.key:active {
  transform: translateY(1px);
}

.key--op {
  background: var(--color-op-bg);
}

.key--op:hover {
  background: var(--color-op-hover-bg);
}

.key--func {
  background: var(--color-func-bg);
}

.key--func:hover {
  background: var(--color-func-hover-bg);
}

.key--wide,
.key--eq {
  grid-column: span 2;
}

.key--eq {
  background: var(--color-eq-bg);
}

.key--eq:hover {
  background: var(--color-eq-hover-bg);
}

.theme-joke .key {
  color: #400000;
}

.theme-joke .key--op,
.theme-joke .key--eq {
  color: #ffffff;
}

.joke-label {
  display: none;
}

.theme-joke .joke-label {
  position: absolute;
  top: -34px;
  left: 50%;
  display: block;
  transform: translateX(-50%);
  padding: 5px 10px;
  border-radius: 5px;
  background-color: var(--color-op-bg);
  color: var(--color-text);
  font-size: 0.9rem;
  font-weight: bold;
  letter-spacing: 1px;
  white-space: nowrap;
  z-index: 10;
  animation: pulse-joke 1s infinite alternate;
}

.calculator.is-movable.theme-joke {
  padding-bottom: 30px;
  overflow: visible;
}

.calculator.is-movable.theme-joke::before,
.calculator.is-movable.theme-joke::after {
  content: "";
  position: absolute;
  bottom: 0;
  width: 10px;
  height: 20px;
  background: #333333;
  border-radius: 5px 5px 0 0;
  z-index: -1;
  transform-origin: top center;
  animation: walk 0.3s infinite alternate;
}

.calculator.is-movable.theme-joke::before {
  left: 20px;
}

.calculator.is-movable.theme-joke::after {
  right: 20px;
  animation-delay: 0.15s;
}

.calculator:not(.is-dragging).theme-joke::before,
.calculator:not(.is-dragging).theme-joke::after {
  animation-play-state: paused;
  transform: rotate(0deg);
}

.site-footer {
  position: fixed;
  left: 50%;
  bottom: 16px;
  width: min(92%, 560px);
  transform: translateX(-50%);
  text-align: center;
  font-size: 0.85rem;
  opacity: 0.85;
  z-index: 10;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  border: 0;
  clip: rect(0, 0, 0, 0);
}

@keyframes pulse-joke {
  0% {
    transform: translateX(-50%) scale(1);
    opacity: 0.8;
  }

  50% {
    transform: translateX(-50%) scale(1.05);
    opacity: 1;
  }

  100% {
    transform: translateX(-50%) scale(1);
    opacity: 0.8;
  }
}

@keyframes walk {
  0% {
    transform: rotate(0deg);
    box-shadow: 0 5px 0 0 #000000;
  }

  50% {
    transform: rotate(8deg);
    box-shadow: 0 2px 0 0 #000000;
  }

  100% {
    transform: rotate(0deg);
    box-shadow: 0 5px 0 0 #000000;
  }
}

@keyframes phone-jump {
  0% {
    transform: translate(-50%, -50%) scale(1);
  }

  30% {
    transform: translate(-50%, -62%) scale(1.05) rotate(-2deg);
  }

  60% {
    transform: translate(-50%, -46%) scale(0.98) rotate(2deg);
  }

  100% {
    transform: translate(-50%, -50%) scale(1);
  }
}

@media (max-width: 768px) {
  .site-header {
    top: 16px;
    width: min(94%, 430px);
    flex-direction: column;
    justify-content: center;
    gap: 12px;
  }

  .site-title {
    font-size: 1.7rem;
    text-align: center;
  }

  .theme-switcher {
    justify-content: center;
  }

  .calculator {
    width: min(360px, calc(100vw - 24px));
    padding: 18px;
  }

  .display {
    height: 58px;
    font-size: 1.8rem;
    line-height: 38px;
  }

  .key {
    height: 56px;
    font-size: 1.25rem;
  }
}

@media (max-width: 480px) {
  .site-header {
    top: 12px;
    width: calc(100% - 24px);
  }

  .site-title {
    font-size: 1.45rem;
  }

  .theme-button {
    width: 24px;
    height: 24px;
  }

  .joke-button {
    width: 42px;
    height: 24px;
    font-size: 9px;
  }

  .calculator {
    position: fixed;
    top: 50%;
    left: 50%;
    width: calc(100vw - 20px);
    max-width: 340px;
    padding: 14px;
    border-radius: 18px;
    transform: translate(-50%, -50%) !important;
    cursor: default;
    touch-action: manipulation;
  }

  .calculator.is-movable,
  .calculator.is-dragging {
    cursor: default;
  }

  .calculator.phone-jump {
    animation: phone-jump 0.35s ease;
  }

  .display {
    height: 54px;
    margin-bottom: 8px;
    padding: 9px;
    font-size: 1.55rem;
    line-height: 36px;
  }

  .keys {
    gap: 8px;
  }

  .key {
    height: 50px;
    border-radius: 12px;
    font-size: 1.1rem;
  }

  .theme-joke .joke-label {
    top: -30px;
    font-size: 0.75rem;
  }

  .site-footer {
    bottom: 10px;
    font-size: 0.72rem;
  }
}

@media (max-width: 360px) {
  .site-title {
    font-size: 1.3rem;
  }

  .calculator {
    width: calc(100vw - 16px);
    padding: 12px;
  }

  .display {
    height: 48px;
    font-size: 1.35rem;
    line-height: 30px;
  }

  .keys {
    gap: 7px;
  }

  .key {
    height: 46px;
    font-size: 1rem;
  }

  .site-footer {
    font-size: 0.68rem;
  }
}