/* Tidings coming soon：整页是一只航空信封。
   边框是航空条纹，左上寄件人是 Tidings，右上邮票和邮戳，右下收件人栏就是表单。 */

:root {
  --paper: #E1EAF0;      /* 航空信纸的浅蓝 */
  --paper-hi: #F5F8FA;   /* 条纹间隙、输入框、邮票纸 */
  --ink: #15213A;
  --ink-soft: #4B5874;
  --air-red: #C2303B;
  --air-red-deep: #A12530;
  --air-blue: #23428B;
  --hand: #2B3F9F;       /* 圆珠笔蓝，只给手写地址用 */
  --cancel: #565A78;     /* 邮戳油墨 */
  --stripe: 14;
  --gutter: clamp(20px, 4.5vw, 64px);
  color-scheme: light;
}

*, *::before, *::after { box-sizing: border-box; }

html, body { background: var(--paper); }

body {
  margin: 0;
  color: var(--ink);
  font-family: "Archivo", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 1.0625rem;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

.visually-hidden {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip-path: inset(50%); white-space: nowrap;
}

/* 信封 */

.envelope {
  min-height: 100vh;
  min-height: 100dvh;
  border: calc(var(--stripe) * 1px) solid transparent;
  border-image-source: repeating-linear-gradient(-45deg,
    var(--air-red) 0 16px, var(--paper-hi) 16px 24px,
    var(--air-blue) 24px 40px, var(--paper-hi) 40px 48px);
  border-image-slice: var(--stripe);
  padding: var(--gutter);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  grid-template-rows: auto 1fr auto auto;
  grid-template-areas: "top" "message" "recipient" "bottom";
  row-gap: clamp(36px, 6vh, 72px);
}

/* 寄件人 */

.top {
  grid-area: top;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
}

.sender p { margin: 0; }

.wordmark {
  font-weight: 800;
  font-stretch: 125%;
  font-size: clamp(1.35rem, 1.1rem + 1vw, 1.9rem);
  letter-spacing: .05em;
  text-transform: uppercase;
  line-height: 1;
}

.sender-line {
  margin-top: .45rem !important;
  font-family: "Courier Prime", ui-monospace, monospace;
  font-size: .9rem;
  color: var(--ink-soft);
}

.airmail-label {
  display: inline-block;
  margin-top: 1rem !important;
  padding: .32rem .6rem .26rem;
  border: 1.5px solid var(--air-blue);
  color: var(--air-blue);
  font: 700 .72rem/1 "Courier Prime", ui-monospace, monospace;
  letter-spacing: .14em;
  text-transform: uppercase;
}

/* 邮票和邮戳 */

.postage {
  position: relative;
  flex: none;
  width: 88px;
  margin: 2px 4px 0 0;
  transform: rotate(2.5deg);
}

.stamp {
  display: block;
  width: 100%;
  height: auto;
  filter: drop-shadow(0 1px 1.5px rgb(21 33 58 / .2));
}

.stamp-paper { fill: var(--paper-hi); }
.stamp-perf {
  fill: none;
  stroke: var(--paper);
  stroke-width: 6;
  stroke-dasharray: 0 8;
  stroke-linecap: round;
}
.stamp-field { fill: var(--air-blue); }
.stamp-letter {
  fill: var(--paper-hi);
  font-family: "Archivo", sans-serif;
  font-weight: 800;
  font-stretch: 125%;
  font-size: 52px;
}
.stamp-name, .stamp-value {
  fill: var(--paper-hi);
  font-family: "Courier Prime", monospace;
  font-weight: 700;
  font-size: 8px;
  letter-spacing: 1.5px;
}

.postmark {
  position: absolute;
  width: 190px;
  height: auto;
  left: -172px;
  top: 44px;
  transform: rotate(-12deg);
  mix-blend-mode: multiply;
  opacity: .8;
  pointer-events: none;
}

.pm-line {
  fill: none;
  stroke: var(--cancel);
  stroke-width: 2;
  stroke-linecap: round;
}
.pm-text {
  fill: var(--cancel);
  font-family: "Courier Prime", monospace;
  font-weight: 700;
}
.pm-ring-text { font-size: 7.5px; }
.pm-center { font-size: 8.5px; letter-spacing: 1px; }
.pm-big { font-size: 12px; letter-spacing: 2px; }

/* 正文 */

.message { grid-area: message; }

h1 {
  margin: 0;
  max-width: 11ch;
  font-weight: 760;
  font-stretch: 112%;
  font-size: clamp(2.5rem, 1.3rem + 4.4vw, 5.25rem);
  line-height: .98;
  letter-spacing: -.025em;
  text-wrap: balance;
}

.lede {
  margin: 1.4rem 0 0;
  max-width: 34ch;
  color: var(--ink-soft);
  font-size: clamp(1.05rem, .98rem + .35vw, 1.25rem);
  text-wrap: pretty;
}

/* 收件人栏 */

.recipient {
  grid-area: recipient;
  position: relative;
  width: 100%;
  max-width: 32rem;
}

.to {
  display: flex;
  align-items: baseline;
  gap: .9rem;
  min-height: 3.4rem;
  margin: 0 0 1.6rem;
  padding-bottom: .2rem;
  border-bottom: 1.5px solid var(--ink);
}

.to-label {
  flex: none;
  font: 700 .78rem/1 "Courier Prime", ui-monospace, monospace;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.hand {
  min-width: 0;
  font-family: "Homemade Apple", "Bradley Hand", "Segoe Script", cursive;
  font-size: calc(clamp(1.05rem, .8rem + 1.1vw, 1.55rem) * var(--fit, 1));
  line-height: 1.7;
  color: var(--hand);
  overflow-wrap: anywhere;
  transition: color .2s;
}

.hand.is-placeholder { color: color-mix(in srgb, var(--hand) 40%, var(--paper)); }

.rubber {
  display: none;
  position: absolute;
  right: 0;
  top: -1.4rem;
  padding: .12em .5em .06em;
  border: 3px solid var(--air-red);
  border-radius: 3px;
  color: var(--air-red);
  font-weight: 800;
  font-stretch: 125%;
  font-size: 1.3rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  transform: rotate(-9deg);
  mix-blend-mode: multiply;
  opacity: .9;
  pointer-events: none;
}

.recipient.is-held .rubber { display: inline-block; }

/* 表单 */

.field + .field { margin-top: 1.1rem; }

.field label {
  display: block;
  margin-bottom: .4rem;
  font: 700 .76rem/1.2 "Courier Prime", ui-monospace, monospace;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

input {
  width: 100%;
  min-width: 0;
  padding: .72rem .85rem;
  border: 0;
  background: transparent;
  color: var(--ink);
  font: inherit;
}

input::placeholder { color: color-mix(in srgb, var(--ink-soft) 55%, var(--paper-hi)); }
input:focus { outline: none; }

.handle-input,
.field > input {
  background: var(--paper-hi);
  border: 1.5px solid var(--ink);
  border-radius: 2px;
}

.handle-input { display: flex; align-items: center; }

.suffix {
  padding-right: .85rem;
  font-family: "Courier Prime", ui-monospace, monospace;
  color: var(--ink-soft);
  white-space: nowrap;
}

.handle-input:focus-within,
.field > input:focus-visible {
  outline: 3px solid var(--air-blue);
  outline-offset: 2px;
}

.status, .hint {
  margin: .45rem 0 0;
  font-size: .88rem;
  color: var(--ink-soft);
}
.status { min-height: 1.4em; }
.status[data-state="free"] { color: var(--air-blue); }
.status[data-state="no"] { color: var(--air-red-deep); }

.trap {
  position: absolute;
  left: -9999px;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

button {
  margin-top: 1.5rem;
  padding: .85rem 1.5rem;
  border: 0;
  border-radius: 2px;
  background: var(--air-red);
  color: var(--paper-hi);
  font: inherit;
  font-weight: 700;
  font-stretch: 108%;
  cursor: pointer;
  transition: background .15s;
}
button:hover { background: var(--air-red-deep); }
button:active { transform: translateY(1px); }
button:disabled { opacity: .7; cursor: progress; }
button:focus-visible { outline: 3px solid var(--air-blue); outline-offset: 3px; }

.form-error {
  margin: .8rem 0 0;
  color: var(--air-red-deep);
  font-size: .92rem;
}
.form-error:empty { display: none; }

.held:focus { outline: none; }
.held p { margin: 0; }
.held-title { font-size: 1.15rem; font-weight: 700; }
.held-title span { overflow-wrap: anywhere; }
#held-note { margin-top: .4rem; color: var(--ink-soft); }

/* 页脚 */

.bottom {
  grid-area: bottom;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: .4rem 1.5rem;
  font-family: "Courier Prime", ui-monospace, monospace;
  font-size: .82rem;
  color: var(--ink-soft);
}
.bottom p { margin: 0; }
.bottom a { color: inherit; text-underline-offset: 3px; }
.bottom a:focus-visible { outline: 2px solid var(--air-blue); outline-offset: 2px; }

/* 宽屏：正文在左上，收件人栏在右下，和信封上的位置一样 */

@media (min-width: 880px) {
  .envelope {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
    grid-template-rows: auto 1fr auto;
    grid-template-areas: "top top" "message recipient" "bottom bottom";
    column-gap: clamp(32px, 5vw, 80px);
  }
  .message { align-self: start; padding-top: clamp(0px, 4vh, 40px); }
  .recipient { align-self: end; justify-self: end; }
}

@media (max-width: 560px) {
  :root { --stripe: 10; }
  .postage { width: 70px; }
  .postmark { width: 150px; left: -116px; top: 16px; }
  .pm-wave { display: none; }  /* 窄屏上波浪线会压到 PAR AVION 标签 */
  .suffix { font-size: .85rem; padding-right: .6rem; }
}

/* 没跑 JS 时表单提交后的结果页 */

.envelope.envelope--plain {
  grid-template-columns: minmax(0, 36rem);
  grid-template-rows: auto;
  grid-template-areas: none;
  place-content: center;
}
.plain h1 { font-size: clamp(2rem, 1.4rem + 3vw, 3.5rem); }
.plain p { color: var(--ink-soft); }
.plain a { color: var(--air-blue); }

/* 开场：先手写地址，再盖邮戳。用户一开始输入就取消。 */

@media (prefers-reduced-motion: no-preference) {
  .js .hand.is-intro { clip-path: inset(0 100% 0 0); }
  .js.is-ready .hand.is-intro { animation: write 1.5s linear .15s forwards; }
  .js .postmark { opacity: 0; }
  .js.is-ready .postmark { animation: cancel .32s cubic-bezier(.3, 1.5, .5, 1) 1.75s forwards; }
  .recipient.is-held .rubber { animation: thump .28s cubic-bezier(.3, 1.6, .5, 1) both; }
}

@keyframes write {
  from { clip-path: inset(0 100% 0 0); }
  to { clip-path: inset(0 0 0 0); }
}
@keyframes cancel {
  from { opacity: 0; transform: rotate(-12deg) scale(1.3); }
  to { opacity: .8; transform: rotate(-12deg) scale(1); }
}
@keyframes thump {
  from { opacity: 0; transform: rotate(-9deg) scale(1.4); }
  to { opacity: .9; transform: rotate(-9deg) scale(1); }
}