为什么容器在块后不扩展？

body,
html {
  min-height: 100%;
}

.b-page-wrapper {
  height: 100%;
}

p {
  margin-top: 500px;
}

.b-header {
  background-color: #fafafa;
  -webkit-box-align: center;
  -webkit-align-items: center;
  -ms-flex-align: center;
  -ms-grid-row-align: center;
  align-items: center;
  border-bottom: 0;
  padding-left: 23px;
  padding-right: 25px;
  height: 60px;
  -webkit-box-orient: horizontal;
  -webkit-flex-direction: row;
  -ms-flex-direction: row;
  flex-direction: row;
  -webkit-box-pack: justify;
  -webkit-justify-content: space-between;
  -ms-flex-pack: justify;
  justify-content: space-between;
  border: 2px solid #000;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
}

.b-container {
  height: -webkit-calc(100% - 60px);
  height: calc(100% - 60px);
  min-height: 600px;
  position: relative;
  border: 2px solid #000;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
}

.b-aside {
  width: -webkit-calc(20% + 9px);
  width: calc(20% + 9px);
  background-color: #202020;
  border-right: solid 2px #000;
}

.b-main {
  display: inline-block;
  width: -webkit-calc(80% - 9px);
  width: calc(80% - 9px);
  background-color: #fafafa;
}

.b-aside--project-diary {
  width: -webkit-calc(100%/3 - 41px);
  width: calc(100%/3 - 41px);
  border-right: 0;
  border-left: solid 2px #000;
  background-color: transparent;
  background-image: -webkit-gradient(linear, left top, left bottom, from(#facf61), to(#fa5d5d)), -webkit-gradient(linear, left bottom, left top, from(#e0093d), to(#fff));
  background-image: -webkit-linear-gradient(top, #facf61, #fa5d5d), -webkit-linear-gradient(bottom, #e0093d, #fff);
  background-image: linear-gradient(to bottom, #facf61, #fa5d5d), linear-gradient(to top, #e0093d, #fff);
  width: -webkit-calc(20% + 9px);
  width: calc(20% + 9px);
  background-color: #202020;
  border-right: solid 2px #000;
}

.b-tool-project__add {
  margin-bottom: 585px;
}

<div class="b-page-wrapper">
  <header class="b-header">header</header>
  <div class="b-container">
    <aside class="b-aside b-aside--max-menu"></aside>
    <main class="b-main b-main--page-project-team">
      <div class="b-tool-project b-tool-project--team">
        <div class="b-tool-project__top b-tool-project__top--team">
          <div class="b-tool-project__title">text</div><a href="javascript:void(0);" title=" Initial brief" class="b-tool-project__link-brief"><i class="icon"></i>text</a>
        </div>
        <div class="b-todo b-todo--team">
          <ul class="b-todo__header-list b-todo__header-list--team">
            <li class="b-todo__header-item">To-do list name</li>
            <li class="b-todo__header-item">Deadline</li>
            <li class="b-todo__header-item">Assigned</li>
          </ul>
          <ul class="b-todo__todo-list">
            <li class="b-todo__todo-item b-todo__todo-item--team"><a href="javascript:void(0);" title="" class="b-todo__link b-todo__link--team"><span class="b-todo__name b-todo__name--team">text</span><span class="b-todo__deadline b-todo__deadline--team">textm</span><span class="b-todo__assigned b-todo__assigned--team"><span class="b-todo__image-inner"><img src="/images/content/avatar.jpg" alt="Oddity Studio" title="Oddity Studio" class="b-todo__image b-todo__image--team"></span><span class="b-todo__assigned-text b-todo__assigned-text--team">text</span></span></a>
            </li>
            <li class="b-todo__todo-item b-todo__todo-item--team"><a href="javascript:void(0);" title="" class="b-todo__link b-todo__link--team"><span class="b-todo__name b-todo__name--team">text</span><span class="b-todo__deadline b-todo__deadline--team">text</span><span class="b-todo__assigned b-todo__assigned--team"><span class="b-todo__image-inner"><img src="/images/content/avatar.jpg" alt="Client" title="Client" class="b-todo__image b-todo__image--team"></span><span class="b-todo__assigned-text b-todo__assigned-text--team">text</span></span></a>
            </li>
            <li class="b-todo__todo-item b-todo__todo-item--team"><a href="javascript:void(0);" title="" class="b-todo__link b-todo__link--team"><span class="b-todo__name b-todo__name--team">text</span><span class="b-todo__deadline b-todo__deadline--team">text</span><span class="b-todo__assigned b-todo__assigned--team"><span class="b-todo__image-inner"><img src="/images/content/avatar.jpg" alt="Oddity Studio Super long name" title="Oddity Studio Super long name" class="b-todo__image b-todo__image--team"></span><span class="b-todo__assigned-text b-todo__assigned-text--team">text</span></span></a>
            </li>
          </ul>
        </div>
        <div class="b-tool-project__add b-tool-project__add--team"><a href="javascript:void(0);" title="Add task" class="b-tool-project__link-add"><i class="icon-icon-"></i>text</a>
        </div>
        <div class="b-tool-project__text-block b-tool-project__text-block--team">
          <div class="b-tool-project__text">text</div>
        </div>
      </div>
    </main>
    <aside class="b-aside b-aside--project-diary"></aside>
  </div>