body {
  background: url("https://img.freepik.com/premium-photo/abstract-blurred-sky-colorful_40299-22.jpg")
    no-repeat center center fixed;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

/* 移动端适配：基础媒体查询 */
@media (max-width: 600px) {
  html {
    font-size: 14px;
  }
  body {
    min-height: 100vh;
    overflow-x: hidden;
    overflow-y: auto;
  }
  .modal {
    position: static;
    left: unset;
    top: unset;
    transform: none;
    width: 20rem;
    max-width: 100vw;
    min-width: unset;
    max-height: 90vh;
    height: auto;
    padding: 0.7rem 0.8rem;
    border-radius: 1.2rem;
    box-sizing: border-box;
    overflow-y: auto;
    margin: 1.2rem auto;
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
  }
  .field {
    font-size: 1.1rem;
    min-height: 2.5rem;
    padding: 0 0.6rem 0.1rem 0.6rem;
    border-radius: 0.7rem;
  }
  .sign {
    height: 2.3rem;
    font-size: 0.9rem;
    padding: 0 0.7rem 0.1rem 0.6rem;
    border-radius: 0.6rem;
  }
  button#download-btn {
    padding: 0.6rem 0.8rem;
    font-size: 1rem;
    border-radius: 0.6rem;
    width: 100%;
    margin-top: 0.7rem;
  }
  .signature-main {
    min-height: 2.2rem;
    flex-wrap: wrap;
    gap: 0.2rem;
  }
  .signed-by {
    font-size: 1rem;
  }
}



@import url("https://fonts.googleapis.com/css2?family=Instrument+Sans:ital,wght@0,400..700;1,400..700&family=JetBrains+Mono:ital,wght@0,100..800;1,100..800&display=swap");

button#download-btn {
  padding: 5px 10px;
  font-size: 12px;
  cursor: pointer;
  background-color: #007bff;
  color: white;
  border: none;
  border-radius: 5px;
  font-family: "JetBrains Mono", monospace;
  font-optical-sizing: auto;
  font-style: normal;
  text-transform: uppercase;
  font-size: 14px;
  letter-spacing: 0.02em;
  background: #000;
}

.modal {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 36px;
  width: 380px;
  height: 52px;
  padding: 24px;
  border-radius: 40px;
  overflow: visible; /* 允许内容溢出，移动端下会被媒体查询覆盖为auto */
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.5) 0%,
    rgba(255, 255, 255, 0.2) 100%
  );
  box-shadow: 0 0 16px 0 rgba(0, 0, 0, 0);
  transition: 0.4s ease height, 0.4s ease padding, 0.2s border-radius,
    0.6s ease box-shadow;
}
.modal:hover {
  box-shadow: 0 24px 48px -24px rgba(0, 0, 0, 0.025);
}

.modal.active {
  height: auto;
  padding: 32px;
  border-radius: 48px;
}
@media (max-width: 600px) {
  .modal.active {
    height: auto;
    padding: 14px 4vw;
    border-radius: 20px;
  }
}

.field-wrapper {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

.field {
  font-family: "Instrument Sans", sans-serif;
  font-optical-sizing: auto;
  font-style: normal;
  /*   font-variation-settings: "wdth" 100; */
  font-size: 20px;
  display: flex;
  align-items: center;
  min-height: 48px;
  border-radius: 16px;
  border: 1px solid rgba(0, 0, 0, 0.05);
  padding: 0 12px 2px 12px;
  background: none;
  color: #000;
  outline: none;
  transition: border 0.2s;
}
.active .field {
  border: 1px solid rgba(0, 0, 0, 0.5);
}

.field::placeholder {
  opacity: 0.5;
  color: #000;
}

.sign,
.signed-by {
  font-family: "JetBrains Mono", monospace;
  font-optical-sizing: auto;
  font-style: normal;
  text-transform: uppercase;
  font-size: 14px;
  letter-spacing: 0.02em;
}
.active .signed-by {
  opacity: 1;
}

.sign {
  position: absolute;
  right: 4px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  gap: 8px;
  align-items: center;
  height: 44px;
  border-radius: 12px;
  padding: 0 14px 2px 12px;
  background: #000;
  color: #fff;
  border: none;
  opacity: 0.2;
  transition: 0.2s;
}
.active .sign {
  opacity: 1;
}

.signature {
  border-bottom: 1px solid rgba(0, 0, 0, 0.25);
}

.letter-bank {
  display: none;
}

.signed-by {
  color: rgba(0, 0, 0, 0.5);
  opacity: 0;
  padding-bottom: 2px;
  transition: 0.2s ease;
}

.signature-main {
  display: flex;
  min-height: 51px;
  flex-flow: wrap;
  justify-content: start;
}

.signature-main svg path {
  stroke-linejoin: round;
  stroke-linecap: round;
  stroke-width: 1;
  stroke: #000;
  transition: 0.2s stroke-dashoffset;
}

.up,
.lo {
  max-height: 51px;
}

/* letter boxes */
.up.a {
  margin: 0 -10px 0 -7px;
}
.up.b {
  margin: 0 -5px 0 -13px;
}
.up.c {
  margin: 0 -5px 0 -6px;
}
.up.d {
  margin: 0 -6px 0 -6px;
}
.up.e {
  margin: 0 -10px 0 -8px;
}
.up.f {
  margin: 0 -13px 0 -5px;
}
.up.g {
  margin: 0 0px 0 -6px;
}
.up.h {
  margin: 0 -8px 0 -6px;
}
.up.i {
  margin: 0 -25px 0 -16px;
}
.up.j {
  margin: 0 -24px 0 -6px;
}
.up.k {
  margin: 0 -23px 0 -3px;
}
.up.l {
  margin: 0 -7px 0 -5px;
}
.up.m {
  margin: 0 -7px 0 -10px;
}
.up.n {
  margin: 0 -4px 0 -10px;
}
.up.o {
  margin: 0 -1px 0 -1px;
}
.up.p {
  margin: 0 -12px 0 -3px;
}
.up.q {
  margin: 0 -3px 0 -3px;
}
.up.r {
  margin: 0 -8px 0 -4px;
}
.up.s {
  margin: 0 -14px 0 -2px;
}
.up.t {
  margin: 0 -29px 0 -17px;
}
.up.u {
  margin: 0 -10px 0 -1px;
}
.up.v {
  margin: 0 -15px 0 -6px;
}
.up.w {
  margin: 0 -8px 0 -6px;
}
.up.x {
  margin: 0 -11px 0 -13px;
}
.up.y {
  margin: 0 -12px 0 2px;
}
.up.z {
  margin: 0 -9px 0 -8px;
}
.lo.a {
  margin: 0 -4px 0 0;
}
.lo.b {
  margin: 0 -6px 0 -1.5px;
}
.lo.c {
  margin: 0 -4px 0 0;
}
.lo.d {
  margin: 0 -11.3px 0 0;
}
.lo.e {
  margin: 0 -4px 0 0;
}
.lo.f {
  margin: 0 -6px 0 -6px;
}
.lo.g {
  margin: 0 -4px 0 -10px;
}
.lo.h {
  margin: 0 -4px 0 -1px;
}
.lo.i {
  margin: 0 -3.5px 0 0;
}
.lo.j {
  margin: 0 -5px 0 -14px;
}
.lo.k {
  margin: 0 -6.5px 0 0;
}
.lo.l {
  margin: 0 -12px 0 -4px;
}
.lo.m,
.lo.n {
  margin: 0 -5px 0 0;
}
.lo.o {
  margin: 0 -2.5px 0 0;
}
.lo.p {
  margin: 0 -2.5px 0 -10px;
}
.lo.q {
  margin: 0 -2px 0 -6px;
}
.lo.r {
  margin: 0 -3px 0 -1px;
}
.lo.s {
  margin: 0 -4px 0 -4px;
}
.lo.t {
  margin: 0 -12.5px 0 -3.5px;
}
.lo.u,
.lo.v {
  margin: 0 -4.5px 0 0;
}
.lo.w,
.lo.x {
  margin: 0 -4px 0 0;
}
.lo.y {
  margin: 0 -4px 0 -9px;
}
.lo.z {
  margin: 0 -4px 0 -10px;
}

/* letter paths */
.up.a path {
  stroke-dasharray: 190;
  stroke-dashoffset: 190;
}
.up.b path {
  stroke-dasharray: 230;
  stroke-dashoffset: 230;
}
.up.c path {
  stroke-dasharray: 101;
  stroke-dashoffset: 101;
}
.up.d path {
  stroke-dasharray: 194;
  stroke-dashoffset: 194;
}
.up.e path {
  stroke-dasharray: 132;
  stroke-dashoffset: 132;
}
.up.f path {
  stroke-dasharray: 191;
  stroke-dashoffset: 191;
}
.up.g path {
  stroke-dasharray: 145;
  stroke-dashoffset: 145;
}
.up.h path {
  stroke-dasharray: 235;
  stroke-dashoffset: 235;
}
.up.i path {
  stroke-dasharray: 128;
  stroke-dashoffset: 128;
}
.up.j path {
  stroke-dasharray: 174;
  stroke-dashoffset: 174;
}
.up.k path {
  stroke-dasharray: 244;
  stroke-dashoffset: 244;
}
.up.l path {
  stroke-dasharray: 83;
  stroke-dashoffset: 83;
}
.up.m path {
  stroke-dasharray: 176;
  stroke-dashoffset: 176;
}
.up.n path {
  stroke-dasharray: 111;
  stroke-dashoffset: 111;
}
.up.o path {
  stroke-dasharray: 167;
  stroke-dashoffset: 167;
}
.up.p path {
  stroke-dasharray: 203;
  stroke-dashoffset: 203;
}
.up.q path {
  stroke-dasharray: 212;
  stroke-dashoffset: 212;
}
.up.r path {
  stroke-dasharray: 235;
  stroke-dashoffset: 235;
}
.up.s path {
  stroke-dasharray: 100;
  stroke-dashoffset: 100;
}
.up.t path {
  stroke-dasharray: 133;
  stroke-dashoffset: 133;
}
.up.u path {
  stroke-dasharray: 136;
  stroke-dashoffset: 136;
}
.up.v path {
  stroke-dasharray: 100;
  stroke-dashoffset: 100;
}
.up.w path {
  stroke-dasharray: 163;
  stroke-dashoffset: 163;
}
.up.x path {
  stroke-dasharray: 153;
  stroke-dashoffset: 153;
}
.up.y path {
  stroke-dasharray: 162;
  stroke-dashoffset: 162;
}
.up.z path {
  stroke-dasharray: 149;
  stroke-dashoffset: 149;
}

.lo.a path {
  stroke-dasharray: 36;
  stroke-dashoffset: 36;
}
.lo.b path {
  stroke-dasharray: 64;
  stroke-dashoffset: 64;
}
.lo.c path {
  stroke-dasharray: 17;
  stroke-dashoffset: 17;
}
.lo.d path {
  stroke-dasharray: 73;
  stroke-dashoffset: 73;
}
.lo.e path {
  stroke-dasharray: 22;
  stroke-dashoffset: 22;
}
.lo.f path {
  stroke-dasharray: 59;
  stroke-dashoffset: 59;
}
.lo.g path {
  stroke-dasharray: 75;
  stroke-dashoffset: 75;
}
.lo.h path {
  stroke-dasharray: 48;
  stroke-dashoffset: 48;
}
.lo.i path {
  stroke-dasharray: 16;
  stroke-dashoffset: 16;
}
.lo.j path {
  stroke-dasharray: 59;
  stroke-dashoffset: 59;
}
.lo.k path {
  stroke-dasharray: 54;
  stroke-dashoffset: 54;
}
.lo.l path {
  stroke-dasharray: 33;
  stroke-dashoffset: 33;
}
.lo.m path {
  stroke-dasharray: 43;
  stroke-dashoffset: 43;
}
.lo.n path {
  stroke-dasharray: 27;
  stroke-dashoffset: 27;
}
.lo.o path {
  stroke-dasharray: 17;
  stroke-dashoffset: 17;
}
.lo.p path {
  stroke-dasharray: 67;
  stroke-dashoffset: 67;
}
.lo.q path {
  stroke-dasharray: 63;
  stroke-dashoffset: 63;
}
.lo.r path {
  stroke-dasharray: 24;
  stroke-dashoffset: 24;
}
.lo.s path {
  stroke-dasharray: 32;
  stroke-dashoffset: 32;
}
.lo.t path {
  stroke-dasharray: 91;
  stroke-dashoffset: 91;
}
.lo.u path {
  stroke-dasharray: 28;
  stroke-dashoffset: 28;
}
.lo.v path {
  stroke-dasharray: 17;
  stroke-dashoffset: 17;
}
.lo.w path {
  stroke-dasharray: 21;
  stroke-dashoffset: 21;
}
.lo.x path {
  stroke-dasharray: 24;
  stroke-dashoffset: 24;
}
.lo.y path {
  stroke-dasharray: 70;
  stroke-dashoffset: 70;
}
.lo.z path {
  stroke-dasharray: 67;
  stroke-dashoffset: 67;
}