// 水平グラデーション
@mixin horizontal($start-color: #555, $end-color: #333, $start-percent: 0%, $end-percent: 100%) {
  background-color: $end-color;
  background-image: linear-gradient(to right, $start-color $start-percent, $end-color $end-percent); // Standard, IE10
  background-repeat: repeat-x;
}

// 垂直グラデーション
@mixin vertical($start-color: #555, $end-color: #333, $start-percent: 0%, $end-percent: 100%) {
  background-color: $end-color;
  background-image: linear-gradient(to bottom, $start-color $start-percent, $end-color $end-percent); // Standard, IE10
  background-repeat: repeat-x;
}

// 指定グラデーション
@mixin directional($start-color: #555, $end-color: #333, $deg: 45deg) {
  background-image: linear-gradient($deg, $start-color, $end-color); // Standard, IE10
  background-repeat: repeat-x;
}

// 3つ水平グラデーション
@mixin horizontal-three-colors($start-color: #00b3ee, $mid-color: #7a43b6, $color-stop: 50%, $end-color: #c3325f) {
  background-image: linear-gradient(to right, $start-color, $mid-color $color-stop, $end-color); // Standard, IE10
  background-repeat: no-repeat;
}

// 3つ垂直グラデーション
@mixin vertical-three-colors($start-color: #00b3ee, $mid-color: #7a43b6, $color-stop: 50%, $end-color: #c3325f) {
  background-image: linear-gradient($start-color, $mid-color $color-stop, $end-color); // Standard, IE10
  background-repeat: no-repeat;
}

// 円形グラデーション
@mixin radial($inner-color: #555, $outer-color: #333) {
  background-image: radial-gradient(circle, $inner-color, $outer-color); // Standard, IE10
  background-repeat: no-repeat;
}

// 縞模様グラデーション
@mixin striped($color: rgba(255, 255, 255, 0.15), $angle: 45deg) {
  background-image: linear-gradient(
    $angle,
    $color 25%,
    transparent 25%,
    transparent 50%,
    $color 50%,
    $color 75%,
    transparent 75%,
    transparent
  ); // Standard, IE10
}
