mkdocs-material/src/assets/stylesheets/layout/_search.scss

/*
 * Copyright (c) 2016 Martin Donath <martin.donath@squidfunk.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

/* ----------------------------------------------------------------------------
 * Search
 * ------------------------------------------------------------------------- */

/*
 * Application search
 */
.md-search {
  position: relative;

  /*
   * Search overlay
   */
  &__overlay {
    display: none;

    /* [mobile -]: Only show overlay on mobile */
    @include break-to-device(mobile) {
      display: block;
      position: absolute;
      top: 0.4rem;
      left: 0.4rem;
      width: 4.0rem;
      height: 4.0rem;
      overflow: hidden;
      z-index: 0;
      opacity: 0;
      background: #EEEEEE;
      border-radius: 100%;
      transform-orgin: center;
      transition: opacity   .2s .2s,
                  transform .3s .1s;

      /*
       * Expanded overlay
       */
      #md-toggle-search:checked ~ .md-header & {
        z-index: 1;
        opacity: 1;
        transform: scale(40);
        transition: opacity   .1s,
                    transform .4s;
      }
    }
  }

  /*
   * Inner wrapper
   */
  &__inner {
    padding: 0.8rem 0.8rem 0;

    /* [tablet +]: Header-embedded search */
    @include break-from-device(tablet) {
      padding: 0.4rem;
    }
  }

  /*
   * Search form
   */
  &__form {
    position: relative;
    text-align: right;
    border-radius: px2rem(2px);

    /* [mobile -]: Add drop-shadow on mobile */
    @include break-to-device(mobile) {
      @include z-depth(2);
    }
  }

  /*
   * Icon
   */
  &__icon {
    position: absolute;
    top: 0.8rem;
    left: 1.2rem;
    font-size: 2.4rem;
    transition: color .25s;
    cursor: pointer;


    /* [mobile -]: Use back arrow as search icon */
    @include break-to-device(mobile) {
      top: 1.2rem;

      /* Hack: @extend doesn't work in media queries, so override manually */
      &:before {
        content: "arrow_back";
      }
    }
  }

  /*
   * Search field
   */
  &__input {
    padding: 0 0.8rem 0 6.4rem;
    border-radius: px2rem(2px);

    /*
     * Placeholder and icon color in active state
     */
    + .md-search__icon,
    &::placeholder {
      color: $md-color-black--light;
    }

    /* [mobile -]: Full-screen search bar */
    @include break-to-device(mobile) {
      width: 100%;
      height: 4.8rem;
      font-size: 1.8rem;
    }

    /* [tablet +]: Header-embedded search */
    @include break-from-device(tablet) {
      width: 23.0rem;
      height: 4.0rem;
      padding-left: 4.8rem;
      font-size: ms(0);
      background: $md-color-white--lightest;
      color: $md-color-white;
      transition: color            .25s,
                  background-color .25s,
                  width            .25s cubic-bezier(0.1, 0.7, 0.1, 1.0);

      /*
       * Placeholder color
       */
      + .md-search__icon,
      &::placeholder {
        color: $md-color-white;
        transition: color .25s;
      }

      /*
       * Active search field
       */
      &:focus {
        background: $md-color-white;
        color: $md-color-black;
        width: 40.0rem;

        /*
         * Placeholder and icon color in active state
         */
        + .md-search__icon,
        &::placeholder {
          color: $md-color-black--light;
        }
      }
    }
  }
}