/* Coach — mobile-first, iPad Safari friendly, light/dark aware. */
:root {
  --bg: #f6f4ee; --card: #ffffff; --ink: #1f2328; --muted: #6b7280; --line: #e5e1d8;
  --accent: #1f6f5f; --accent-ink: #ffffff; --soft: #e8f1ee; --warn: #b45309; --danger: #b91c1c;
  --coach: #f0f6f4; --user: #fff7e6; --radius: 14px; --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #14171a; --card: #1d2126; --ink: #e8e6e1; --muted: #9aa3ad; --line: #2c333a; --accent: #4fb39b; --accent-ink: #0d1412; --soft: #1f2d29; --coach: #1b2622; --user: #2a2418; }
}
* { box-sizing: border-box; }
html, body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--font); font-size: 17px; -webkit-text-size-adjust: 100%; }
a { color: var(--accent); }
button, .btn { font: inherit; border: 1px solid var(--line); background: var(--card); color: var(--ink); border-radius: 999px; padding: 10px 16px; cursor: pointer; min-height: 44px; }
button.primary, .btn.primary { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); font-weight: 600; }
button:disabled { opacity: .5; }
input, select, textarea { font: inherit; color: var(--ink); background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 12px; width: 100%; }
textarea { resize: none; line-height: 1.35; }
.wrap { max-width: 860px; margin: 0 auto; padding: 16px; }
header.top { display: flex; align-items: center; gap: 12px; padding: 10px 16px; border-bottom: 1px solid var(--line); background: var(--card); position: sticky; top: 0; z-index: 5; padding-top: calc(10px + env(safe-area-inset-top)); }
header.top .brand { font-weight: 800; letter-spacing: .3px; text-decoration: none; color: var(--ink); font-size: 20px; }
header.top .spacer { flex: 1; }
header.top nav a { margin-left: 12px; font-size: 15px; text-decoration: none; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin-bottom: 14px; }
.muted { color: var(--muted); }
.small { font-size: 14px; }
h1 { font-size: 24px; margin: 8px 0 12px; } h2 { font-size: 18px; margin: 18px 0 8px; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { border: 1px solid var(--line); background: var(--card); border-radius: 999px; padding: 8px 14px; min-height: 40px; font-size: 15px; cursor: pointer; }
.chip.on { background: var(--soft); border-color: var(--accent); color: var(--accent); font-weight: 600; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 10px; }
.subject { display: block; text-decoration: none; color: var(--ink); background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px; }
.subject .em { font-size: 28px; } .subject .nm { font-weight: 600; margin-top: 4px; }
.list a { display: block; padding: 12px 0; border-bottom: 1px solid var(--line); text-decoration: none; color: var(--ink); }
.list a:last-child { border-bottom: 0; }
.tag { display: inline-block; font-size: 12px; padding: 2px 8px; border-radius: 999px; background: var(--soft); color: var(--accent); margin-right: 6px; }
/* chat */
.chat { display: flex; flex-direction: column; min-height: calc(100vh - 60px); }
.messages { flex: 1; padding: 12px 12px 8px; display: flex; flex-direction: column; gap: 10px; max-width: 860px; width: 100%; margin: 0 auto; }
.msg { border-radius: var(--radius); padding: 12px 14px; line-height: 1.45; max-width: 92%; overflow-wrap: anywhere; }
.msg.user { background: var(--user); align-self: flex-end; white-space: pre-wrap; }
.msg.coach { background: var(--coach); align-self: flex-start; }
.msg.coach p:first-child { margin-top: 0; } .msg.coach p:last-child { margin-bottom: 0; }
.msg.coach pre { overflow-x: auto; background: rgba(0,0,0,.06); padding: 10px; border-radius: 8px; }
.msg.coach table { border-collapse: collapse; } .msg.coach td, .msg.coach th { border: 1px solid var(--line); padding: 4px 8px; }
.msg .att { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 6px; }
.msg .att img { max-height: 160px; border-radius: 8px; border: 1px solid var(--line); }
.msg .att .file { font-size: 13px; padding: 4px 8px; border-radius: 8px; background: rgba(0,0,0,.06); }
.status { font-size: 13px; color: var(--muted); padding: 0 16px 4px; max-width: 860px; margin: 0 auto; width: 100%; min-height: 18px; }
.composer { position: sticky; bottom: 0; background: var(--card); border-top: 1px solid var(--line); padding: 10px 12px calc(10px + env(safe-area-inset-bottom)); }
.composer .inner { max-width: 860px; margin: 0 auto; display: flex; flex-direction: column; gap: 8px; }
.composer .row { display: flex; gap: 8px; align-items: flex-end; }
.composer textarea { flex: 1; min-height: 46px; max-height: 40vh; }
.composer .icon { width: 46px; min-width: 46px; height: 46px; padding: 0; display: inline-flex; align-items: center; justify-content: center; font-size: 22px; }
.previews { display: flex; gap: 6px; flex-wrap: wrap; }
.previews .pv { position: relative; font-size: 13px; background: var(--soft); border-radius: 8px; padding: 6px 28px 6px 8px; }
.previews .pv button { position: absolute; right: 2px; top: 2px; min-height: 0; padding: 0 6px; border: 0; background: transparent; }
.modes { display: flex; gap: 6px; overflow-x: auto; -webkit-overflow-scrolling: touch; padding-bottom: 2px; }
.modes .chip { white-space: nowrap; }
.login { max-width: 380px; margin: 12vh auto; }
.bar { height: 8px; background: var(--line); border-radius: 4px; overflow: hidden; } .bar > i { display: block; height: 100%; background: var(--accent); }
table.data { width: 100%; border-collapse: collapse; font-size: 15px; } table.data td, table.data th { text-align: left; padding: 6px 4px; border-bottom: 1px solid var(--line); vertical-align: top; }
.err { color: var(--danger); }
.katex-display { overflow-x: auto; }