/* DEBUG */

* {
/*   outline: thin solid orange;*/
}

.inner {
/*   border: thin solid orange;*/
}

header, footer, .users {
/*   border: thick solid green;*/
}

/* Custom properties and typography */

:root {
   --base-font-size: 16px;
   --0-5v: .125rem;
   --1v: .25rem;
   --1-5v: .375rem;
   --2v: .5rem;
   --3v: .75rem;
   --3-5v: .875rem;
   --4v: 1rem; /* relative to --base-font-size */
   --4-5v: 1.125rem;
   --5v: 1.25rem;
   --5-5v: 1.375rem;
   --6v: 1.5rem;
   --7v: 1.75rem;
   --8v: 2rem;
   --10v: 2.5rem;
   --12v: 3rem;
   --13v: 3.25rem;
   --16v: 4rem;
   --18v: 4.5rem;
   --32v: 8rem;
   --cLight: white;
   --cDarkUltra: black;
   --cDark-100: #121615; /* sideral black C84M70Y57K80 -> RGB */
   --cDark-90: #2a2d2c;
   --cDark-80: #414544;
   --cDark-70: #595c5b;
   --cDark-60: #717373;
   --cDark-50: #888a8a;
   --cDark-35: #acadab;
   --cDark-30: #b8b4b9;
   --cDark-25: #c4c5c4;
   --cDark-20: #d0d0d0;
   --cDark-15: #dbdcdc;
   --cDark-10: #e7e8e9; /* meteor gray */
   --cPrimary: hsl(210, 58%, 46%);
   --cPrimaryDark: hsl(210, 66%, 40%);
   --cPrimaryLight: hsl(210, 100%, 74%);
   --cPrimaryGray: hsl(210, 10%, 95%);
   --xs: 575px;
   --md: 768px;
   --lg: 960px;
}

@font-face {
   font-display: swap;
   font-family: 'Arago';
   font-style: normal;
   font-weight: 500;
   src: url('../Arago-Medium.otf');
}

@font-face {
   font-display: swap;
   font-family: 'Arago';
   font-style: normal;
   font-weight: 600;
   src: url('../Arago-SemiBold.otf');
}

@font-face {
   font-display: swap;
   font-family: 'Gilroy';
   font-style: normal;
   font-weight: 400;
   src: url('../Gilroy-Regular.otf');
}

@font-face {
   font-display: swap;
   font-family: 'Gilroy';
   font-style: normal;
   font-weight: 500;
   src: url('../Gilroy-Medium.otf');
}

@font-face {
   font-display: swap;
   font-family: 'Gilroy';
   font-style: normal;
   font-weight: 600;
   src: url('../Gilroy-SemiBold.otf');
}

/* Common */

body {
   background-color: var(--cLight);
   color: var(--cDark-100);
   font-family: 'Gilroy', sans-serif;
   font-size: var(--base-font-size);
   font-weight: 500;
   line-height: 1.5;
}

footer {
   background-color: var(--cDarkUltra);
   color: var(--cLight);
}

section {
   padding: var(--16v) var(--4v);
}

section:nth-child(2n + 1) {
   background-color: var(--cPrimaryGray);
}

h1, h2, h3, h4 {
   font-family: 'Arago', sans-serif;
   font-weight: 600;
   line-height: 1.15;
   text-align: left;
}

h1 {
   font-size: var(--10v);
}

h2 {
   color: var(--cPrimary);
   font-size: var(--8v);
   padding: 0 0 var(--5v);
   position: relative;
}

h2:before {
   background-color: var(--cPrimary);
   border-radius: 4px;
   bottom: 0;
   content: '';
   height: 4px;
   left: 0;
   position: absolute;
   width: 6rem;
}

h3 {
   font-size: var(--6v);
   margin: var(--8v) 0 var(--6v);
}

img {
   display: block;
}

.icon,
label {
   align-items: center; /* vertical center :before if any */
   display: inline-flex;
}

.icon:before {
   aspect-ratio: 1;
   background-color: var(--cDark-100);
   content: '';
   height: var(--6v);
   margin-right: var(--0-5v);
   mask-size: contain;
}

abbr {
   text-transform: uppercase;
   white-space: nowrap;
}

cite {
   font-style: italic;
}

sup {
   font-size: smaller;
   vertical-align: super;
}

ul:not([class]) li {
   padding: 0 0 0 var(--6v);
   position: relative;
}

ul:not([class]) li::before {
   background-color: var(--cDark-100);
   border-radius: 50%;
   content: '';
   height: var(--2v);
   left: 0;
   position: absolute;
   top: var(--2v);
   width: var(--2v);
}

ul:not([class]) li ul, ul:not([class]) li + li {
   margin: var(--2v) 0 0;
}

ul:not([class]) li ul li:before {
   background-color: unset;
   border: 2px solid var(--cDark-50);
}

h2,
p:not(:last-child),
ul:not(:last-child) {
   margin: 0 0 var(--6v);
}

h2:not(:first-of-type) {
   margin-top: var(--18v);
}

/* Top bar */

.topbar {
   align-items: center;
   background-color: var(--cPrimaryGray);
   color: var(--cDark-80);
   display: flex;
   font-size: .75rem;
   font-weight: 400;
   gap: var(--4v);
   justify-content: center;
   letter-spacing: 3px;
   padding: var(--2v);
}

.topbarlogo {
   margin: auto;
   max-height: var(--4v);
}

.topbarlabel {
   display: none;
}

/* Header */

header {
   padding: var(--3-5v) var(--4v);
}

.header-inner {
   display: grid;
   gap: 0 var(--8v);
   grid-template-areas: 'home-link actionbar' 'main-nav main-nav';
   grid-template-rows: var(--10v);
}

.headerlogo {
   aspect-ratio: 200 / 131; /* intrinsic aspect ratio - set width needed for grid-template-columns min-content */
   grid-area: home-link;
   justify-self: start;
   height: 2.875rem;
}

.actionbar {
   align-items: center;
   display: flex;
   gap: var(--4v);
   grid-area: actionbar;
   justify-self: end;
}

.actionbar label {
   cursor: pointer;
   padding: var(--1v) var(--2v);
}

.lang {
   border: 1px solid var(--cDark-70);
   border-radius: var(--8v); /* 6v(h icon) + 2 * 1v (vpad) */
   color: var(--cDark-70);
   font-size: .875rem;
   padding: var(--0-5v) var(--1-5v) var(--0-5v) var(--0-5v);
   text-transform: uppercase;
}

.lang:before {
   mask-image: url('../language_24dp_1F1F1F_FILL0_wght200_GRAD0_opsz24.svg');
}

.menubtn:before {
   mask-image: url('../menu_24dp_1F1F1F_FILL0_wght400_GRAD0_opsz24.svg');
}

.menubtn:checked:before {
   mask-image: url('../close_24dp_1F1F1F_FILL0_wght400_GRAD0_opsz24.svg');
}

/* Main navigation */

.menu-wrapper {
   display: none;
   grid-area: main-nav;
}

body:has(.menubtn:checked) {
   overflow: hidden;
}

header:has(.menubtn:checked) {
   background-image:
      linear-gradient(
         to bottom, 
         rgb(255 255 255 / 1),
         rgb(255 255 255 / 0.1)),
      url('../bg-lowpoly.svg');
   background-position: bottom;
   background-repeat: no-repeat;
   background-size: cover;
   height: 100vh;
}

.actionbar:has(.menubtn:checked) + .menu-wrapper {
   display: block;
   font-size: var(--6v);
   font-weight: 600;
   hyphens: none;
   padding: calc(var(--12v) + var(--2v)) 0;
}

ul.menu {
   display: flex;
   flex-flow: column wrap;
   gap: var(--8v);
}

ul.menu li {
   text-align: center;
}

ul.menu li a {
   display: block;
   padding: var(--2v) 0;
}

/* Footer */

footer {
   padding: var(--4v) var(--4v) var(--6v);
}

.footer-inner {
   align-items: center;
   display: flex;
   flex-flow: column wrap;
   gap: var(--4v);
}

ul.footerlinks {
   display: flex;
   flex-flow: row wrap;
   gap: var(--2v) var(--8v);
   justify-content: center;
   margin: 0;
   white-space: nowrap;
}

.footerlinks li {
   flex-grow: 1;
   text-align: center;
}

.footerlinks li a {
   display: block;
   padding: var(--2v) 0;
}

.footerlogo {
   margin: auto;
   max-height: var(--6v);
}

/* Content */

section:first-of-type {
   background-blend-mode: darken;
   background-color: rgb(12 16 15 / .75);
   background-image: url('../bg-solarsystem.webp');
   background-position: 20% 0;
   background-repeat: no-repeat;
   background-size: cover;
   color: var(--cLight);
}

.emphase {
   font-size: var(--4-5v);
   font-weight: 400;
   margin: var(--8v) 0;
   padding: 0 0 0 var(--6v);
   position: relative;
}

.emphase:last-child {
   margin: var(--8v) 0 0 0;
}

.emphase:before {
   position: absolute;
   background-color: var(--cDark-50);
   border-radius: 4px;
   bottom: 0;
   content: '';
   left: 0;
   top: 0;
   width: 4px;
}

/* Home content */

.home h1 {
   text-align: center;
}

.baseline {
   font-size: var(--5-5v);
   font-weight: 400;
   margin: var(--2v) 0 0; /* space between h1 and baseline */
   text-align: center;
}

.baseline:before, .baseline:after {
   content: '–';
   padding: 0 var(--1v);
}

.about-inner {
   display: grid;
   gap: var(--12v);
   grid-template-columns: auto;
}

.aboutnumbers {
   display: grid;
   gap: var(--4v);
   grid-template-columns: 1fr 1fr;
}

.aboutnumbers li {
   border: 2px solid var(--cDark-60);
   border-radius: var(--2v);
   display: flex;
   flex-direction: column;
   justify-content: center;
   opacity: .9;
   padding: var(--4v);
   text-align: center;
}

.aboutnumbers .number {
   display: block;
   color: var(--cPrimaryLight);
   font-size: var(--6v);
   font-weight: 600;
   line-height: 1.15;
}

.users {
   background-color: var(--cPrimaryGray);
   padding: var(--10v) var(--4v) var(--12v);
}

.users .inner {
   border-top: 1px solid var(--cDark-100);
}

.users h3 {
   background-color: var(--cPrimaryGray);
   display: block;
   font-size: var(--4v);
   font-variant: all-small-caps;
   font-weight: 400;
   letter-spacing: .1875rem; /* Magic */
   margin: 0 auto var(--8v);
   padding: 0 var(--4v);
   transform: translateY(-50%);
   width: fit-content;
}

.userslogos {
   align-items: center;
   display: flex;
   flex-flow: row wrap;
   gap: var(--7v);
   justify-content: space-evenly;
}

.userslogos img {
   height: var(--16v);
}

.userslogos img.esa {
   height: var(--8v);
}

/* Contacts content */

.contacts-container {
   display: grid;
   gap: var(--12v);
   grid-template-columns: auto;
}

.contactsemail,
.contactsmail {
   background-blend-mode: exclusion;
   background-color: var(--cLight);
   background-position: top var(--6v) center;
   background-repeat: no-repeat;
   background-size: var(--16v);
   border: 1px solid var(--cDark-20);
   border-radius: var(--2v);
   padding: calc(2 * var(--6v) + var(--16v)) var(--6v) var(--6v);
}

.contactsemail {
   background-image: url('../alternate_email_24dp_1F1F1F_FILL0_wght400_GRAD0_opsz24.svg')
}

.contactsmail {
   background-image: url('../mail_24dp_1F1F1F_FILL0_wght400_GRAD0_opsz24.svg')
}

.contacts-container h2 {
   color: var(--cDark-100);
   font-size: var(--6v);
   margin: 0 0 var(--6v);
   padding: 0;
   text-align: center;
}

.contacts-container h2:before {
   all: revert;
}

/* Page content */

.page ul {
   padding: 0 0 0 var(--4v);
}

.page .update {
   color: var(--cDark-80);
   font-size: var(--3-5v);
   padding: var(--4v);
   text-align: right;
}

/* Component - CTA button */

.cta-wrapper {
   display: flex;
   justify-content: center;
   margin: var(--12v) 0 0;
}

.cta {
   background-color: var(--cPrimary);
   border-radius: var(--2v);
   color: var(--cLight);
   font-family: 'Arago', sans-serif;
   font-weight: 500;
   padding: var(--2v) var(--4v);
}

/* Component - Tiles and Tile */

.Tiles {
   display: flex;
   gap: var(--4v);
   margin: var(--12v) 0;
   overflow-x: scroll; /* setup CSS scroll snap */
   scroll-snap-type: x mandatory; /* setup CSS scroll snap */
}

.Tiles:last-child {
   margin: var(--12v) 0 0;
}

.Tile {
   background-color: var(--cLight);
   border-radius: var(--2v);
   isolation: isolate;
   min-width: calc(100% - 2 * var(--4v));
   padding: var(--6v);
   position: relative;
   scroll-snap-align: center; /* setup CSS scroll snap */
}

.Tile:after {
   border: 1px solid var(--cDark-20);
   border-radius: var(--2v);
   content: '';
   height: 100%;
   left: 0;
   position: absolute;
   top: 0;
   width: 100%;
}

.Tile.ondemand:before {
   background-color: var(--cDark-10);
   border-radius: var(--6v); /* font-size(4v) + 2 * hpad(1v) */
   bottom: var(--4v);
   color: var(--cDark-70);
   content: attr(data-label);
   font-size: var(--3-5v);
   padding: var(--1v) var(--3v);
   position: absolute;
   right: var(--4v);
}

.Tile:not(.ondemand):before {
   aspect-ratio: 1;
   background-color: var(--cPrimary);
   bottom: var(--4v);
   content: '';
   height: var(--6v);
   mask-image: url('../arrow_forward_24dp_1F1F1F_FILL0_wght400_GRAD0_opsz24.svg');
   position: absolute;
   right: var(--4v);
}

.Tile h3 {
   color: var(--cPrimary);
   font-weight: 500;
   margin: 0 0 var(--5v);
   text-align: left;
}

.Tile p {
   margin: 0 0 var(--10v);
}

.Tile a:before {
   bottom: 0;
   content: '';
   display: block;
   left: 0;
   position: absolute;
   right: 0;
   top: 0;
   z-index: 1;
}

.Tile ul.tags {
   color: var(--cLight);
   display: flex;
   font-size: var(--3-5v);
   font-weight: 400;
   gap: var(--1v);
   margin: 0 0 var(--2v);
   padding: 0;
}

.Tile ul.tags li {
   background-color: var(--cPrimary);
   border-radius: 2px;
   padding: var(--0-5v) var(--2v);
}

/* Animations */

@media (hover: hover) {
   .menu-mi {
      position: relative;
      transition: color .35s ease;
   }

   .menu-mi:before {
      background-color: var(--cPrimary);
      border-radius: 4px;
      bottom: 0;
      content: '';
      height: 2px;
      position: absolute;
      transform: scaleX(0);
      transition: transform .35s ease;
      width: 50%;
   }

   .menu-mi:before {
      left: 25%;
   }

   .menu-mi:hover {
      color: var(--cPrimary);
   }

   .menu-mi:hover:before {
      transform: scaleX(1);
   }

   .lang {
      transition: color .35s ease, border-color .35s ease;
   }

   .lang:before {
      transition: background-color .35s ease;
   }

   .lang:hover {
      color: var(--cPrimary);
      border-color: var(--cPrimary);
   }

   .lang:hover:before {
      background-color: var(--cPrimary);
   }

   ul.footerlinks li a:hover {
      color: unset;
      transition: none;
   }

   ul.footerlinks li a:before {
      background-color: var(--cLight);
   }

   .cta {
      transition: background-color .35s ease;
   }

   .cta:hover {
      background-color: var(--cPrimaryDark);
   }

   .Tile:after {
      transition: border-color .35s ease;
   }

   .Tile:hover:after {
      border: 2px solid var(--cPrimary);
    }

   .Tile:not(.ondemand):before {
      transition: transform .35s ease;
   }

   .Tile:not(.ondemand):hover:before {
      transform: translateX(var(--2v));
   }
}

/* Responsive */

@media screen and (width >= 576px) {
   .header-inner {
      grid-template-areas: 'home-link main-nav actionbar';
      grid-template-columns: min-content 1fr min-content;
   }

   label:has(.menubtn) {
      display: none;
   }

   .menu-wrapper {
      display: block;
      justify-self: end;
      align-self: center;
   }

   ul.menu {
      flex-flow: row nowrap;
   }

   .Tiles {
      display: grid;
      grid-template-columns: 1fr 1fr;
      overflow: hidden;
      padding: 0;
   }

   h2:not(:first-of-type) {
      margin-top: var(--32v);
   }

   .aboutnumbers {
      grid-template-columns: 1fr 1fr 1fr 1fr;
   }

   .contacts-container {
      grid-template-columns: 1fr 1fr;
   }
}

@media screen and (width >= 768px) {
   .topbarlabel {
      display: block;
   }

   .inner {
      margin: auto;
      max-width: var(--lg);
   }

   footer {
      padding: var(--4v);
   }

   .footer-inner {
      flex-flow: row wrap;
      justify-content: space-between;
   }

   h1 {
      font-size: var(--12v);
   }

   h2 {
      font-size: var(--10v);
      margin-bottom: var(--12v);
   }

   h2:before {
      left: calc(50% - 3rem);
   }

   h1, h2 {
      text-align: center;
   }

   .users h3 {
      font-size: var(--4-5v);
   }

   a:has(.footerlogo) {
      order: -1;
   }

   .about-inner {
      grid-template-columns: auto auto;
   }

   .emphase {
      margin: var(--16v) 0;
   }

   .emphase:last-child {
      margin: var(--16v) 0 0;
   }

   .aboutnumbers {
      grid-template-columns: 1fr;
   }

   .home h2 + p {
      text-align: center;
   }

   .Tiles {
      grid-template-columns: 1fr 1fr 1fr;
   }
}