/* ==========================================================
   Pattern C「冬の手紙」— ネットスクールからのエール
   冬空の紺 × 雪のアイスブルー × 生成りの便箋 × あたたかなテラコッタ
   ========================================================== */
:root {
  --paper: #f7f4ee;
  --paper-2: #eaf0f5;
  --card: #fffdf9;
  --navy: #243b5a;
  --navy-2: #3d5a80;
  --ice: #e3ebf3;
  --accent: #c4654d;
  --accent-dark: #9e4b37;
  --accent-pale: #f8e8e2;
  --amber: #e2b45c;
  --text: #2b2e35;
  --text-soft: #5b606b;
  --line: #e0dacd;
  --hand: "Klee One", "Hiragino Maru Gothic ProN", "Yu Gothic", sans-serif;
  --gothic: "Zen Kaku Gothic New", "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", sans-serif;
  --sans: "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", sans-serif;
  --flake: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cg fill='none' stroke='%233d5a80' stroke-width='1.8' stroke-linecap='round'%3E%3Cpath d='M12 2v20M3.34 7l17.32 10M3.34 17L20.66 7'/%3E%3Cpath d='M9.5 3.5L12 6l2.5-2.5M9.5 20.5L12 18l2.5 2.5M3.6 10.4L6.8 9.5 5.9 6.3M18.1 17.7l-.9-3.2 3.2-.9M3.6 13.6l3.2.9-.9 3.2M18.1 6.3l-.9 3.2 3.2.9'/%3E%3C/g%3E%3C/svg%3E");
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--text); font-family: var(--sans); line-height: 1.9; letter-spacing: .03em; -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
img { max-width: 100%; }
a { color: inherit; }
h1, h2, h3 { margin: 0; font-family: var(--gothic); font-weight: 900; }
.container { width: min(1080px, calc(100% - 32px)); margin-inline: auto; }
.narrow { width: min(820px, calc(100% - 32px)); }
.center, .center-text { text-align: center; }
.sp { display: none; }

/* ---------- header ---------- */
.site-header { display: flex; align-items: center; gap: 12px; min-height: 64px; padding: 0 clamp(16px, 4vw, 56px); background: #fff; border-bottom: 1px solid var(--line); }
.logo img { display: block; height: 26px; width: auto; }
.header-tag { padding: 3px 10px; border-radius: 4px; background: var(--ice); color: var(--navy); font-size: 12px; font-weight: 700; white-space: nowrap; }
.header-btn { margin-left: auto; padding: 8px 16px; border-radius: 6px; background: var(--navy); color: #fff; font-size: 13px; font-weight: 700; text-decoration: none; white-space: nowrap; }

/* ---------- hero ---------- */
.hero { position: relative; overflow: hidden; padding: 64px 16px 130px; background:
  radial-gradient(circle at 15% 30%, rgba(255,255,255,.55) 0 1.6px, transparent 2.6px) 0 0 / 64px 64px,
  radial-gradient(circle at 70% 70%, rgba(255,255,255,.4) 0 1.2px, transparent 2.2px) 0 0 / 46px 46px,
  linear-gradient(180deg, #1f3452 0%, #2e4d74 60%, #5f7fa3 100%); }
.hero-card { position: relative; z-index: 1; max-width: 760px; margin: 0 auto; padding: 56px clamp(20px, 5vw, 56px) 48px; border-radius: 6px; background: var(--card); text-align: center; box-shadow: 0 24px 60px rgba(10,25,45,.35); }
.hero-card::before { content: ""; position: absolute; inset: 10px; border: 1px dashed var(--line); border-radius: 4px; pointer-events: none; }
.stamp { position: absolute; top: -24px; right: clamp(16px, 5vw, 40px); display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 4px; width: 92px; height: 108px; background: var(--ice); color: var(--navy); border: 4px dotted var(--card); outline: 2px solid var(--navy-2); transform: rotate(5deg); font-family: var(--gothic); font-size: 12px; font-weight: 900; line-height: 1.3; text-align: center; }
.stamp svg { width: 40px; height: 40px; }
.hero-to { margin: 0 0 14px; color: var(--navy-2); font-family: var(--hand); font-size: 17px; font-weight: 600; }
.hero h1 { color: var(--navy); font-size: clamp(32px, 5.6vw, 56px); line-height: 1.4; }
.hero h1 span { color: var(--accent); background: linear-gradient(transparent 70%, var(--accent-pale) 70%); }
.hero-lead { margin: 18px 0 30px; color: var(--text-soft); font-size: 16px; }
.hero-offer { position: relative; margin: 0 auto 24px; padding: 34px 20px 22px; border: 2px solid var(--navy); border-radius: 8px; background: #fff; }
.offer-ribbon { position: absolute; top: -18px; left: 50%; margin: 0; padding: 4px 26px; transform: translateX(-50%); background: var(--navy); color: #fff; font-family: var(--gothic); font-size: 15px; font-weight: 900; white-space: nowrap; clip-path: polygon(0 0, 100% 0, 96% 50%, 100% 100%, 0 100%, 4% 50%); }
.offer-main { margin: 0; font-size: clamp(16px, 2.4vw, 20px); font-weight: 700; line-height: 1.75; }
.offer-main strong { color: var(--accent); }
.offer-zero { margin: 14px 0 0; padding-top: 12px; border-top: 1px dashed var(--line); color: var(--text-soft); font-size: 14px; }
.offer-zero b { margin-left: 10px; color: var(--accent); font-family: var(--gothic); font-size: 40px; line-height: 1; vertical-align: -6px; }
.offer-zero small { font-size: 18px; }
.hero-period { margin: 0 0 26px; font-size: 17px; font-weight: 700; }
.hero-period span { display: block; color: var(--accent); font-size: 12px; letter-spacing: .14em; }
.btn { display: inline-block; padding: 16px 40px; border-radius: 999px; background: var(--accent); color: #fff; font-size: 15px; font-weight: 700; text-decoration: none; box-shadow: 0 6px 0 var(--accent-dark); transition: transform .2s, box-shadow .2s; }
.btn:hover { transform: translateY(-2px); box-shadow: 0 8px 0 var(--accent-dark); }
.hero-drift { position: absolute; left: 0; bottom: -1px; width: 100%; height: 100px; }

/* ---------- common ---------- */
section { padding: 90px 0; }
section h2 { color: var(--navy); font-size: clamp(25px, 3.6vw, 36px); line-height: 1.5; }
section h2::before { content: ""; display: block; width: 26px; height: 26px; margin: 0 auto 10px; background: var(--flake) center / contain no-repeat; opacity: .8; }
h2.small { font-size: 26px; }

/* ---------- letter ---------- */
.letter-sec { padding-top: 50px; }
.letter { position: relative; margin-top: 40px; padding: 52px clamp(22px, 6vw, 64px) 46px; border-top: 6px solid var(--navy); border-radius: 4px; background: var(--card); box-shadow: 0 2px 0 var(--line), 0 18px 40px rgba(36,59,90,.1); font-family: var(--hand); font-size: 17px; line-height: 2.2; }
.letter p { margin: 0 0 1.6em; }
.letter-to { color: var(--navy); font-weight: 600; font-size: 19px; }
.letter mark { background: linear-gradient(transparent 60%, rgba(226,180,92,.4) 60%); color: inherit; font-weight: 600; }
.letter-sign { margin: 0 !important; text-align: right; color: var(--navy); font-weight: 600; font-size: 18px; }

/* ---------- postcards ---------- */
.cards-sec { background: var(--paper-2); }
.postcards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; margin-top: 44px; }
.postcard { position: relative; padding: 30px 24px 26px; background: var(--card); box-shadow: 0 10px 26px rgba(36,59,90,.1); }
.postcard:nth-child(1) { transform: rotate(-1.2deg); }
.postcard:nth-child(2) { transform: rotate(.8deg); }
.postcard:nth-child(3) { transform: rotate(-.5deg); }
.postcard::before { content: ""; position: absolute; top: 14px; right: 16px; width: 34px; height: 40px; border: 2px dotted var(--navy-2); background: var(--ice) var(--flake) center / 20px no-repeat; }
.pc-to { margin: 0 44px 12px 0; padding-bottom: 10px; border-bottom: 2px solid var(--navy); color: var(--navy); font-family: var(--gothic); font-size: 17px; font-weight: 900; line-height: 1.5; }
.postcard p:last-child { margin: 0; color: var(--text-soft); font-family: var(--hand); font-size: 15px; line-height: 1.95; }

/* ---------- mechanism ---------- */
.mech-lead { margin: 20px 0 40px; text-align: center; font-size: 16px; line-height: 2; }
.mech-lead strong { color: var(--accent); }
.receipts { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.receipt { position: relative; padding: 26px 24px 30px; background: #fff; border: 1px solid var(--line);
  -webkit-mask: radial-gradient(circle 7px at 50% 100%, transparent 98%, #000) 0 0 / 18px 100%; mask: radial-gradient(circle 7px at 50% 100%, transparent 98%, #000) 0 0 / 18px 100%; }
.rc-title { margin: 0 0 14px; padding-bottom: 10px; border-bottom: 2px dashed var(--line); font-family: var(--gothic); font-size: 17px; font-weight: 900; text-align: center; }
.receipt dl { margin: 0; }
.receipt dl div { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 10px 4px; border-bottom: 1px dotted var(--line); }
.receipt dt { font-weight: 700; }
.receipt dd { margin: 0; color: var(--text-soft); font-size: 14px; text-align: right; line-height: 1.5; }
.rc-total { margin: 16px 0 0; text-align: center; font-size: 13px; color: var(--text-soft); }
.rc-total b { display: block; color: var(--text); font-family: var(--gothic); font-size: 20px; }
.receipt.is-cp { background: #fffaf6; }
.is-cp .rc-title { color: var(--navy); }
.rc-ns dd { color: var(--accent); font-weight: 700; }
.is-cp .rc-total b { color: var(--accent); font-size: 24px; }
.rc-stamp { position: absolute; right: 14px; top: 10px; display: grid; place-items: center; width: 48px; height: 48px; border: 3px solid var(--accent); border-radius: 50%; color: var(--accent); font-family: var(--gothic); font-size: 13px; font-weight: 900; transform: rotate(-14deg); opacity: .8; }
.mech-foot { margin: 28px 0 0; text-align: center; font-family: var(--hand); font-size: 19px; font-weight: 600; color: var(--navy); }

/* ---------- overview ---------- */
.check-sec { background: var(--card); }
.check-list { margin: 36px 0 0; padding: 0; list-style: none; }
.check-list li { display: grid; grid-template-columns: 130px 1fr; gap: 18px; padding: 18px 0; border-bottom: 1px dashed var(--line); }
.ck-label { align-self: start; padding: 4px 0; border-radius: 4px; background: var(--navy); color: #fff; font-size: 13px; font-weight: 700; text-align: center; }
.check-list b { display: block; font-size: 16px; line-height: 1.6; }
.check-list p { margin: 4px 0 0; color: var(--text-soft); font-size: 13px; }
.note { margin: 16px 0 0; color: var(--text-soft); font-size: 13px; }

/* ---------- jaccs ---------- */
.jaccs-sec .center-text { margin: 18px 0 26px; color: var(--text-soft); }
.dot-list { margin: 0 0 26px; padding: 22px 26px; list-style: none; border-radius: 8px; background: var(--ice); }
.dot-list li { position: relative; padding: 4px 0 4px 24px; font-size: 15px; }
.dot-list li::before { content: ""; position: absolute; left: 0; top: 12px; width: 15px; height: 15px; background: var(--flake) center / contain no-repeat; }
.pay-tags { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.pay-tags p { margin: 0; padding: 18px 10px; border: 2px solid var(--navy); border-radius: 8px; background: #fff; text-align: center; font-family: var(--gothic); font-size: 19px; font-weight: 900; color: var(--navy); }
.pay-tags span { display: block; color: var(--text-soft); font-family: var(--sans); font-size: 12px; font-weight: 500; }
.important { margin: 24px 0 0; padding: 16px 20px; border-left: 5px solid var(--accent); background: var(--accent-pale); font-weight: 700; font-size: 15px; }
.important span { display: inline-block; margin-right: 10px; padding: 1px 8px; border-radius: 3px; background: var(--accent); color: #fff; font-size: 12px; }

/* ---------- flow ---------- */
.flow-sec { background: var(--paper-2); }
.precheck { margin: 34px 0 28px; padding: 18px 22px; border: 2px dashed var(--accent); border-radius: 8px; background: #fff; }
.precheck b { color: var(--accent); }
.precheck p { margin: 4px 0 0; font-size: 14px; }
.flow-list { margin: 0; padding: 0; list-style: none; }
.flow-list li { display: grid; grid-template-columns: 56px 1fr; gap: 18px; margin-bottom: 14px; padding: 22px 22px 22px 18px; border-radius: 8px; background: #fff; }
.fl-no { display: grid; place-items: center; width: 52px; height: 52px; border-radius: 50%; background: var(--navy); color: #fff; font-family: var(--gothic); font-size: 24px; font-weight: 900; }
.flow-list h3 { margin-bottom: 4px; font-size: 18px; color: var(--navy); }
.flow-list p { margin: 0; color: var(--text-soft); font-size: 14px; }
.flow-list li.is-key { outline: 3px solid var(--accent); }
.flow-list li.is-key .fl-no { background: var(--accent); }
.fl-key { margin-top: 10px !important; padding: 8px 14px; border-radius: 6px; background: var(--accent-pale); color: var(--accent-dark) !important; font-weight: 700; }

/* ---------- caution ---------- */
.caution-sec { padding-top: 70px; }
.caution-list { margin: 26px 0 0; padding: 0; list-style: none; }
.caution-list li { position: relative; padding: 10px 0 10px 22px; border-bottom: 1px dotted var(--line); color: var(--text-soft); font-size: 14px; }
.caution-list li::before { content: "※"; position: absolute; left: 0; top: 10px; }
.caution-list strong { color: var(--accent); }

/* ---------- closing ---------- */
.closing { padding: 90px 16px; background:
  radial-gradient(circle at 20% 30%, rgba(255,255,255,.4) 0 1.4px, transparent 2.4px) 0 0 / 56px 56px,
  linear-gradient(180deg, #2e4d74, #1f3452); color: #fff; text-align: center; }
.closing h2::before { display: none; }
.closing-flake { display: block; width: 34px; height: 34px; margin: 0 auto 14px; color: #c9d8e8; }
.closing-hand { margin: 0 0 12px; font-family: var(--hand); font-size: 18px; color: #f3dcae; }
.closing h2 { margin-bottom: 30px; color: #fff; }
.closing-period { margin: 24px 0 0; font-size: 13px; opacity: .9; }

/* ---------- social / footer ---------- */
.social { padding: 30px 16px; background: var(--paper-2); text-align: center; font-size: 14px; }
.site-footer { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 32px; padding: 32px clamp(16px, 4vw, 56px); background: #fff; color: #646a75; font-size: 13px; }
.site-footer img { height: 20px; width: auto; opacity: .85; }
.site-footer p { margin: 0; }
.site-footer a { color: var(--navy); }

/* ---------- responsive ---------- */
@media (max-width: 760px) {
  .sp { display: inline; }
  .pc { display: none; }
  .header-tag { display: none; }
  section { padding: 64px 0; }
  .hero { padding: 50px 16px 100px; }
  .hero-card { padding-top: 70px; }
  .stamp { width: 74px; height: 88px; top: -20px; font-size: 10px; }
  .stamp svg { width: 30px; height: 30px; }
  .hero-to { font-size: 15px; }
  .hero-lead { font-size: 15px; }
  .letter { font-size: 15px; line-height: 2.1; }
  .postcards, .receipts, .pay-tags { grid-template-columns: 1fr; }
  .postcard:nth-child(n) { transform: none; }
  .check-list li { grid-template-columns: 1fr; gap: 8px; }
  .ck-label { justify-self: start; padding: 2px 14px; }
  .flow-list li { grid-template-columns: 1fr; gap: 10px; }
  .fl-no { width: 42px; height: 42px; font-size: 20px; }
  .site-footer { justify-content: center; text-align: center; }
}