:root {
  --ink: #17202a;
  --muted: #667085;
  --line: #d9dee7;
  --paper: #fffdf8;
  --paper-warm: #fff7e8;
  --paper-cool: #f7fffb;
  --surface: #ffffff;
  --accent: #2f7a68;
  --accent-strong: #205f50;
  --rose: #d66877;
  --gold: #d7a846;
  --shadow: 0 18px 45px rgba(25, 34, 44, 0.12);
  --lifted-shadow: 0 24px 52px rgba(45, 51, 58, 0.16);
}

* {
  box-sizing: border-box;
}

body {
  position: relative;
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans KR", sans-serif;
  background:
    linear-gradient(110deg, rgba(47, 122, 104, 0.12), transparent 38%),
    linear-gradient(290deg, rgba(214, 104, 119, 0.13), transparent 36%),
    repeating-linear-gradient(90deg, rgba(255, 255, 255, 0.2) 0 1px, transparent 1px 72px),
    #f6f1e8;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.58), rgba(255, 255, 255, 0.08) 42%, rgba(255, 255, 255, 0.42)),
    repeating-linear-gradient(135deg, transparent 0 18px, rgba(47, 122, 104, 0.045) 18px 19px, transparent 19px 56px);
}

button,
input,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

.page-shell {
  width: min(1680px, calc(100% - 28px));
  margin: 0 auto;
  padding: 20px 0 64px;
  transition: filter 180ms ease;
}

.page-shell.is-locked {
  filter: blur(10px);
  pointer-events: none;
  user-select: none;
}

.topbar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding: 8px 0 14px;
}

.hero-copy {
  display: flex;
  align-items: center;
  gap: 16px;
}

.professor-photo {
  position: relative;
  width: clamp(74px, 8vw, 112px);
  aspect-ratio: 1 / 1;
  margin: 0;
  overflow: hidden;
  border: 4px solid rgba(255, 255, 255, 0.86);
  border-radius: 8px;
  box-shadow: 0 16px 34px rgba(23, 32, 42, 0.18);
  transform: rotate(-2deg);
}

.photo-click-button {
  position: absolute;
  left: 50%;
  bottom: 8px;
  min-height: 34px;
  border: 2px solid rgba(255, 255, 255, 0.9);
  border-radius: 999px;
  padding: 0 15px;
  background: linear-gradient(135deg, rgba(215, 168, 70, 0.98), rgba(214, 104, 119, 0.96));
  color: #fff;
  font-size: 0.84rem;
  font-weight: 900;
  letter-spacing: 0;
  white-space: nowrap;
  box-shadow:
    0 0 0 4px rgba(215, 168, 70, 0.2),
    0 10px 22px rgba(23, 32, 42, 0.25);
  transform: translateX(-50%);
  animation: buttonPulse 1.45s ease-in-out infinite;
}

.photo-click-button:hover {
  background: linear-gradient(135deg, rgba(223, 179, 78, 1), rgba(47, 122, 104, 0.96));
  transform: translateX(-50%) scale(1.08);
}

.professor-photo img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.eyebrow {
  margin: 0 0 7px;
  color: var(--accent-strong);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: clamp(1.9rem, 4vw, 3.35rem);
  line-height: 0.98;
  letter-spacing: 0;
  text-shadow: 0 3px 0 rgba(255, 255, 255, 0.78);
}

.session-panel {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 42px;
  color: var(--muted);
  font-size: 0.94rem;
  white-space: nowrap;
}

.paper-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  grid-auto-flow: dense;
  align-items: stretch;
  gap: 22px;
  margin-top: 18px;
  padding-top: 12px;
}

.paper-card {
  position: relative;
  display: block;
  width: 100%;
  min-height: 440px;
  margin: 0;
  padding: 18px 18px 20px;
  overflow: hidden;
  border: 1px solid rgba(23, 32, 42, 0.08);
  border-radius: 8px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.52), transparent 28%),
    var(--paper);
  box-shadow: var(--shadow);
  transform: rotate(-0.7deg);
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.paper-card:nth-child(3n + 2) {
  min-height: 460px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.5), transparent 28%),
    var(--paper-warm);
  transform: rotate(0.8deg);
}

.paper-card:nth-child(3n) {
  min-height: 450px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.48), transparent 28%),
    var(--paper-cool);
  transform: rotate(-0.25deg);
}

.paper-card:nth-child(4n) {
  min-height: 430px;
}

.paper-card:hover {
  box-shadow: var(--lifted-shadow);
  transform: translateY(-4px) rotate(0deg);
}

.paper-card::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(rgba(47, 122, 104, 0.06) 1px, transparent 1px) 0 82px / 100% 32px,
    linear-gradient(90deg, rgba(214, 104, 119, 0.12), transparent 34%) 0 0 / 100% 7px no-repeat,
    radial-gradient(circle at 24px 24px, rgba(215, 168, 70, 0.28), transparent 4px);
}

.paper-card::after {
  content: "";
  position: absolute;
  top: 10px;
  left: 50%;
  width: 76px;
  height: 18px;
  pointer-events: none;
  background: rgba(255, 255, 255, 0.54);
  border: 1px solid rgba(255, 255, 255, 0.72);
  box-shadow: 0 2px 8px rgba(23, 32, 42, 0.08);
  transform: translateX(-50%) rotate(-1deg);
}

.paper-card:nth-child(5n + 1)::after {
  top: 8px;
  left: 34%;
  background: rgba(255, 233, 153, 0.62);
  transform: translateX(-50%) rotate(-7deg);
}

.paper-card:nth-child(5n + 2)::after {
  top: 12px;
  left: 63%;
  width: 70px;
  background: rgba(255, 183, 197, 0.56);
  transform: translateX(-50%) rotate(5deg);
}

.paper-card:nth-child(5n + 3)::after {
  top: 9px;
  left: 48%;
  width: 88px;
  background: rgba(184, 230, 214, 0.58);
  transform: translateX(-50%) rotate(2deg);
}

.paper-card:nth-child(5n + 4)::after {
  top: 14px;
  left: 27%;
  width: 64px;
  background: rgba(200, 213, 255, 0.58);
  transform: translateX(-50%) rotate(8deg);
}

.paper-card:nth-child(5n)::after {
  top: 7px;
  left: 72%;
  width: 82px;
  background: rgba(255, 221, 184, 0.62);
  transform: translateX(-50%) rotate(-4deg);
}

.card-content {
  position: relative;
  z-index: 1;
  display: flex;
  height: 100%;
  min-height: 390px;
  flex-direction: column;
}

.card-head {
  display: flex;
  align-items: center;
  gap: 15px;
  padding-right: 42px;
}

.avatar-button {
  display: flex;
  width: 74px;
  flex: 0 0 auto;
  align-items: center;
  flex-direction: column;
  gap: 5px;
  border: 0;
  padding: 0;
  background: transparent;
  color: inherit;
}

.avatar {
  display: grid;
  width: 64px;
  height: 64px;
  flex: 0 0 auto;
  place-items: center;
  overflow: hidden;
  border: 3px solid rgba(255, 255, 255, 0.86);
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--gold), var(--rose));
  color: white;
  font-weight: 800;
  box-shadow: 0 8px 18px rgba(23, 32, 42, 0.16);
  transition: transform 160ms ease, box-shadow 160ms ease;
}

.avatar-button:hover .avatar {
  box-shadow: 0 12px 24px rgba(23, 32, 42, 0.2);
  transform: translateY(-2px) scale(1.04);
}

.avatar img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.avatar-cta {
  border: 1px solid rgba(255, 255, 255, 0.86);
  border-radius: 999px;
  padding: 2px 7px;
  background: rgba(47, 122, 104, 0.86);
  color: white;
  font-size: 0.65rem;
  font-weight: 900;
  line-height: 1.35;
  white-space: nowrap;
  box-shadow: 0 5px 12px rgba(23, 32, 42, 0.16);
}

.name {
  margin: 0;
  font-size: 1.12rem;
}

.permission {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.83rem;
}

.message {
  flex: 1;
  margin: 18px 0 0;
  overflow: auto;
  padding-right: 4px;
  color: #26323f;
  font-size: 1rem;
  line-height: 1.72;
  white-space: pre-wrap;
}

.message::-webkit-scrollbar {
  width: 7px;
}

.message::-webkit-scrollbar-thumb {
  border-radius: 999px;
  background: rgba(47, 122, 104, 0.26);
}

.paper-card.is-locked .card-content {
  filter: blur(9px);
  pointer-events: none;
  user-select: none;
}

.lock-note {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: grid;
  place-items: center;
  padding: 28px;
  background: rgba(255, 253, 248, 0.34);
  color: #3d4652;
  font-weight: 800;
  text-align: center;
}

.primary-button,
.secondary-button,
.ghost-button {
  min-height: 38px;
  border: 0;
  border-radius: 8px;
  padding: 0 14px;
  font-weight: 800;
}

.primary-button {
  background: var(--accent);
  color: white;
}

.primary-button:hover {
  background: var(--accent-strong);
}

.secondary-button {
  border: 1px solid var(--line);
  background: white;
  color: var(--ink);
}

.ghost-button {
  border: 1px solid rgba(47, 122, 104, 0.22);
  background: rgba(255, 255, 255, 0.6);
  color: var(--accent-strong);
}

.login-overlay {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(246, 241, 232, 0.45);
  backdrop-filter: blur(7px);
}

.login-overlay.is-hidden {
  display: none;
}

.login-card {
  width: min(390px, 100%);
  padding: 28px;
  border: 1px solid rgba(23, 32, 42, 0.08);
  border-radius: 8px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(255, 253, 248, 0.92)),
    white;
  box-shadow: 0 22px 80px rgba(23, 32, 42, 0.18);
}

.login-card h2 {
  margin-bottom: 22px;
  font-size: 2rem;
}

.login-card label {
  display: block;
  margin-bottom: 14px;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 800;
}

.login-card input {
  width: 100%;
  height: 44px;
  margin-top: 7px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0 12px;
  color: var(--ink);
  background: white;
}

.login-card .primary-button {
  width: 100%;
  margin-top: 8px;
}

.login-error {
  min-height: 22px;
  margin-bottom: 8px;
  color: #b42318;
  font-size: 0.9rem;
  font-weight: 700;
}

.toast {
  position: fixed;
  top: 50%;
  left: 50%;
  z-index: 40;
  max-width: min(620px, calc(100% - 32px));
  border: 1px solid rgba(255, 255, 255, 0.78);
  border-radius: 8px;
  padding: 22px 28px;
  background: rgba(23, 32, 42, 0.86);
  color: white;
  font-size: clamp(1.25rem, 3.2vw, 2.2rem);
  font-weight: 800;
  line-height: 1.35;
  text-align: center;
  box-shadow: 0 18px 42px rgba(23, 32, 42, 0.22);
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, calc(-50% - 18px)) scale(0.96);
}

.toast.is-visible {
  animation: toastPop 2.35s ease forwards;
}

.student-pop {
  position: fixed;
  top: 50%;
  left: 50%;
  z-index: 43;
  display: flex;
  align-items: center;
  gap: 22px;
  border: 2px solid rgba(255, 255, 255, 0.82);
  border-radius: 8px;
  padding: 20px 26px 20px 20px;
  background: rgba(255, 253, 248, 0.94);
  box-shadow: 0 26px 70px rgba(23, 32, 42, 0.24);
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, calc(-50% + 16px)) scale(0.92);
}

.student-pop.is-visible {
  animation: studentPop 2.15s ease forwards;
}

.student-pop-media {
  display: grid;
  width: min(38vw, 260px);
  height: min(38vw, 260px);
  min-width: 150px;
  min-height: 150px;
  place-items: center;
  overflow: hidden;
  border: 5px solid white;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), var(--gold), var(--rose));
  color: white;
  font-size: clamp(2rem, 8vw, 4.5rem);
  font-weight: 900;
  box-shadow: 0 14px 34px rgba(23, 32, 42, 0.16);
}

.student-pop-media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.student-pop p {
  margin: 0;
  color: var(--ink);
  font-size: clamp(1.5rem, 4.3vw, 3rem);
  font-weight: 900;
  line-height: 1.15;
  white-space: nowrap;
}

.hero-rain-banner {
  position: fixed;
  top: 74px;
  left: 50%;
  z-index: 45;
  border: 2px solid rgba(255, 255, 255, 0.8);
  border-radius: 999px;
  padding: 13px 24px;
  background: linear-gradient(135deg, rgba(215, 168, 70, 0.95), rgba(214, 104, 119, 0.94));
  color: white;
  font-size: clamp(1.2rem, 3vw, 2rem);
  font-weight: 900;
  text-align: center;
  text-shadow: 0 2px 8px rgba(23, 32, 42, 0.22);
  box-shadow: 0 22px 54px rgba(23, 32, 42, 0.22);
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, -12px) scale(0.92);
}

.hero-rain-banner.is-visible {
  animation: bannerPop 2.8s ease forwards;
}

.professor-pop {
  position: fixed;
  top: 50%;
  left: 50%;
  z-index: 46;
  width: min(72vw, 630px);
  aspect-ratio: 1 / 1;
  border: 6px solid rgba(255, 255, 255, 0.92);
  border-radius: 8px;
  background: white;
  box-shadow: 0 30px 80px rgba(23, 32, 42, 0.28);
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, calc(-50% + 18px)) scale(0.9) rotate(-2deg);
}

.professor-pop.is-visible {
  animation: professorPop 3.15s ease forwards;
}

.professor-pop img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.professor-crown {
  position: absolute;
  left: 50%;
  top: -50px;
  z-index: 1;
  font-size: clamp(2.5rem, 8vw, 5.4rem);
  line-height: 1;
  filter: drop-shadow(0 8px 10px rgba(23, 32, 42, 0.22));
  transform: translateX(-50%) rotate(5deg);
}

.rain-layer {
  position: fixed;
  inset: 0;
  z-index: 44;
  overflow: hidden;
  pointer-events: none;
}

.rain-drop {
  position: absolute;
  top: -56px;
  left: var(--left);
  color: var(--drop-color);
  font-size: var(--size);
  line-height: 1;
  animation: iconRain var(--duration) linear forwards;
  animation-delay: var(--delay);
}

@keyframes toastPop {
  0% {
    opacity: 0;
    transform: translate(-50%, calc(-50% - 18px)) scale(0.96);
  }
  14%,
  78% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
  100% {
    opacity: 0;
    transform: translate(-50%, calc(-50% - 12px)) scale(0.98);
  }
}

@keyframes bannerPop {
  0% {
    opacity: 0;
    transform: translate(-50%, -12px) scale(0.92);
  }
  16%,
  78% {
    opacity: 1;
    transform: translate(-50%, 0) scale(1);
  }
  100% {
    opacity: 0;
    transform: translate(-50%, -10px) scale(0.96);
  }
}

@keyframes professorPop {
  0% {
    opacity: 0;
    transform: translate(-50%, calc(-50% + 18px)) scale(0.9) rotate(-2deg);
  }
  14%,
  78% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1) rotate(-1deg);
  }
  100% {
    opacity: 0;
    transform: translate(-50%, calc(-50% - 16px)) scale(0.98) rotate(1deg);
  }
}

@keyframes studentPop {
  0% {
    opacity: 0;
    transform: translate(-50%, calc(-50% + 16px)) scale(0.92);
  }
  14%,
  76% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
  100% {
    opacity: 0;
    transform: translate(-50%, calc(-50% - 12px)) scale(0.98);
  }
}

@keyframes iconRain {
  0% {
    opacity: 0;
    transform: translate3d(0, -40px, 0) rotate(0deg);
  }
  8% {
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: translate3d(var(--drift), calc(100vh + 100px), 0) rotate(var(--spin));
  }
}

@keyframes buttonPulse {
  0%,
  100% {
    box-shadow:
      0 0 0 4px rgba(215, 168, 70, 0.18),
      0 10px 22px rgba(23, 32, 42, 0.25);
    transform: translateX(-50%) scale(1);
  }
  50% {
    box-shadow:
      0 0 0 8px rgba(215, 168, 70, 0.1),
      0 13px 26px rgba(23, 32, 42, 0.28);
    transform: translateX(-50%) scale(1.05);
  }
}

@media (max-width: 980px) {
  .page-shell {
    width: min(100% - 28px, 980px);
  }

  .paper-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .paper-card,
  .paper-card:nth-child(n) {
    grid-column: span 1;
    min-height: 440px;
    transform: none;
  }
}

@media (max-width: 680px) {
  .page-shell {
    width: min(100% - 24px, 1180px);
    padding-top: 18px;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero-copy {
    width: 100%;
    align-items: center;
    flex-direction: row;
    gap: 16px;
  }

  .professor-photo {
    width: 96px;
  }

  h1 {
    font-size: clamp(1.85rem, 10vw, 3rem);
  }

  .session-panel {
    width: 100%;
    justify-content: space-between;
  }

  .paper-grid {
    grid-template-columns: 1fr;
    gap: 16px;
    margin-top: 8px;
  }

  .paper-card,
  .paper-card:nth-child(n) {
    grid-column: span 1;
    min-height: 500px;
    padding: 17px;
    margin-top: 0;
    transform: none;
  }

  .card-content {
    min-height: 455px;
  }

  .message {
    font-size: 1rem;
    line-height: 1.75;
  }

  .student-pop {
    width: min(100% - 28px, 360px);
    align-items: center;
    flex-direction: column;
    gap: 14px;
    padding: 18px;
  }

  .student-pop-media {
    width: min(70vw, 230px);
    height: min(70vw, 230px);
  }

  .student-pop p {
    white-space: normal;
  }

  .professor-pop {
    width: min(90vw, 495px);
  }

  .professor-crown {
    top: -38px;
  }
}