/* ─── commerce_international.css — Thème : Diplomatique, bleu marine, or ───── */
@import url('https://fonts.googleapis.com/css2?family=Cormorant+Garamond:ital,wght@0,300;0,400;0,600;0,700;1,300;1,400;1,600&family=Mulish:wght@300;400;500;600;700&family=Roboto+Mono:wght@400;500&display=swap');

:root {
  --navy:#0f1f3d; --navy-2:#1a3260; --navy-pale:#eff6ff;
  --gold:#c9922a; --gold-2:#d4a017; --gold-pale:#fefce8; --gold-mid:#fde68a;
  --white:#ffffff; --off-white:#f8fafc; --gray-50:#f1f5f9; --gray-100:#e2e8f0;
  --ink:#0a0f1e; --ink-mid:#2d4270; --ink-light:#5a7ab0;
  --teal:#0e7490; --teal-pale:#ecfeff; --red:#b91c1c; --red-pale:#fef2f2;
  --border:#d4dff0; --shadow:0 1px 3px rgba(15,31,61,.08);
  --font-display:'Cormorant Garamond',Georgia,serif;
  --font-body:'Mulish',sans-serif;
  --font-mono:'Roboto Mono',monospace;
  --sidebar-w:270px; --radius:6px;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
html{scroll-behavior:smooth;}

body{
  font-family:var(--font-body);background:var(--white);color:var(--ink);font-size:16.5px;line-height:1.78;
  background-image:radial-gradient(circle, var(--gray-100) 1px, transparent 1px);
  background-size:32px 32px;background-attachment:fixed;
}

.progress-bar{position:fixed;top:0;left:0;height:4px;width:0%;background:linear-gradient(90deg,var(--navy),var(--gold));z-index:200;transition:width .08s linear;}

.page-layout{display:flex;min-height:100vh;}

.sidebar{width:var(--sidebar-w);flex-shrink:0;background:var(--navy);position:sticky;top:0;height:100vh;overflow-y:auto;display:flex;flex-direction:column;scrollbar-width:thin;scrollbar-color:var(--navy-2) transparent;}
.sidebar-header{padding:30px 22px 22px;border-bottom:1px solid rgba(255,255,255,.08);position:relative;overflow:hidden;}
.sidebar-header::after{content:'🌐';position:absolute;right:-8px;top:-8px;font-size:4rem;opacity:.05;}
.sidebar-site-link{font-family:var(--font-mono);font-size:.6rem;letter-spacing:.15em;color:rgba(255,255,255,.3);text-decoration:none;display:block;margin-bottom:12px;}
.sidebar-title{font-family:var(--font-display);font-size:1.45rem;font-weight:600;color:#fff;line-height:1.2;font-style:italic;}
.sidebar-title em{color:var(--gold-2);}
.toc-nav{padding:12px 0 16px;flex:1;}
.toc-section-label{font-family:var(--font-mono);font-size:.58rem;letter-spacing:.2em;text-transform:uppercase;color:rgba(255,255,255,.25);padding:10px 22px 4px;}
.toc-link{display:block;padding:5px 22px 5px 26px;font-family:var(--font-body);font-size:.82rem;font-weight:400;color:rgba(255,255,255,.52);text-decoration:none;border-left:2px solid transparent;transition:all .15s;}
.toc-link:hover,.toc-link.active{color:#fff;border-left-color:var(--gold);background:rgba(201,146,42,.1);}
.toc-link.active{color:var(--gold-mid);}
.sidebar-subject-nav{padding:14px 22px;border-top:1px solid rgba(255,255,255,.08);}
.sidebar-subject-nav p{font-family:var(--font-mono);font-size:.58rem;letter-spacing:.15em;text-transform:uppercase;color:rgba(255,255,255,.22);margin-bottom:8px;}
.sidebar-subject-nav a{display:block;font-family:var(--font-body);font-size:.82rem;color:rgba(255,255,255,.38);text-decoration:none;padding:3px 0;transition:color .15s;}
.sidebar-subject-nav a:hover{color:var(--gold-mid);}
.sidebar-subject-nav a.current{color:var(--gold-mid);font-weight:600;}

.main{flex:1;min-width:0;padding:0 60px 100px;max-width:840px;background:var(--white);}

.page-header{padding:58px 0 40px;margin-bottom:52px;border-bottom:1px solid var(--border);position:relative;}
.page-header::after{content:'';position:absolute;bottom:0;left:0;width:120px;height:3px;background:linear-gradient(90deg,var(--navy),var(--gold));}
.subject-tag{font-family:var(--font-mono);font-size:.62rem;letter-spacing:.22em;text-transform:uppercase;color:var(--navy-2);margin-bottom:14px;}
h1.page-title{font-family:var(--font-display);font-size:3.6rem;font-weight:600;color:var(--ink);line-height:1.0;letter-spacing:-.01em;font-style:italic;}
.page-intro{margin-top:18px;font-size:1rem;color:var(--ink-mid);font-style:italic;max-width:540px;font-family:var(--font-display);}

.section{margin-bottom:64px;scroll-margin-top:28px;}
h2.section-title{font-family:var(--font-display);font-size:2rem;font-weight:600;color:var(--ink);margin-bottom:22px;padding-bottom:10px;border-bottom:2px solid var(--navy);display:flex;align-items:baseline;gap:14px;font-style:italic;}
h2.section-title .num{font-family:var(--font-mono);font-size:.72rem;color:white;background:var(--navy);padding:3px 9px;border-radius:3px;font-weight:400;font-style:normal;}
h3.sub-title{font-family:var(--font-display);font-size:1.35rem;font-weight:600;color:var(--navy-2);margin:30px 0 12px;font-style:italic;}
p{margin-bottom:.92em;}ul,ol{padding-left:1.4em;margin-bottom:.9em;}li{margin-bottom:.28em;}

.box{padding:17px 21px 15px;margin:20px 0;border-radius:var(--radius);box-shadow:var(--shadow);}
.box-label{font-family:var(--font-display);font-size:.72rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;display:block;margin-bottom:8px;font-style:normal;}
.box.def{background:var(--navy-pale);border:1px solid #bfdbfe;border-left:5px solid var(--navy);}
.box.def .box-label{color:var(--navy);}
.box.theorem{background:var(--gold-pale);border:1px solid var(--gold-mid);border-left:5px solid var(--gold);}
.box.theorem .box-label{color:var(--gold);}
.box.prop{background:var(--teal-pale);border:1px solid #a5f3fc;border-left:5px solid var(--teal);}
.box.prop .box-label{color:var(--teal);}
.box.corollary{background:var(--red-pale);border:1px solid #fecaca;border-left:5px solid var(--red);}
.box.corollary .box-label{color:var(--red);}
.box.example{background:var(--gray-50);border:1px solid var(--gray-100);}
.box.example .box-label{color:var(--ink-mid);}
.box.remark{background:var(--off-white);border:1px dashed var(--border);}
.box.remark .box-label{color:var(--ink-light);}

.proof-toggle{display:inline-flex;align-items:center;gap:6px;font-family:var(--font-display);font-style:italic;font-size:.9rem;color:var(--navy);border:1px solid var(--navy);padding:4px 14px;border-radius:var(--radius);cursor:pointer;background:transparent;margin-top:8px;transition:all .18s;user-select:none;}
.proof-toggle:hover{background:var(--navy);color:#fff;}
.proof-toggle .arrow{transition:transform .2s;font-style:normal;}
.proof-toggle.open .arrow{transform:rotate(90deg);}
.proof-content{max-height:0;overflow:hidden;transition:max-height .3s ease;}
.proof-content.open{max-height:900px;}
.proof-inner{margin-top:12px;padding:14px 18px;background:var(--gray-50);border:1px solid var(--border);border-radius:var(--radius);color:var(--ink-mid);font-size:.94rem;font-style:italic;}
.qed{float:right;color:var(--navy);font-family:var(--font-display);font-style:normal;}

.formula-block{text-align:center;padding:20px 16px;margin:18px 0;background:var(--off-white);border:1px solid var(--border);border-radius:var(--radius);overflow-x:auto;box-shadow:var(--shadow);}

.math-table{width:100%;border-collapse:collapse;margin:16px 0;font-size:.91rem;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);}
.math-table th{background:var(--navy);color:#fff;padding:10px 14px;text-align:left;font-family:var(--font-display);font-size:1rem;font-style:italic;}
.math-table td{padding:9px 14px;border-bottom:1px solid var(--border);vertical-align:top;}
.math-table tr:nth-child(even) td{background:var(--gray-50);}
.math-table td:first-child{font-family:var(--font-display);font-style:italic;color:var(--navy-2);}
code{font-family:var(--font-mono);font-size:.82em;background:var(--navy-pale);color:var(--navy);padding:2px 6px;border-radius:3px;border:1px solid #bfdbfe;}
.two-col{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:14px 0;}
.two-col .box{margin:0;}

.mobile-header{display:none;position:sticky;top:0;z-index:50;background:var(--navy);padding:12px 18px;align-items:center;justify-content:space-between;}
.mobile-menu-btn{background:none;border:none;color:var(--gold-mid);font-size:1.3rem;cursor:pointer;}
.mobile-title{font-family:var(--font-display);font-size:1.1rem;color:#fff;font-style:italic;}
.mobile-drawer{display:none;position:fixed;inset:0;z-index:100;}
.mobile-drawer.open{display:flex;}
.drawer-overlay{position:absolute;inset:0;background:rgba(0,0,0,.5);}
.drawer-panel{position:relative;z-index:1;width:270px;background:var(--navy);height:100%;overflow-y:auto;padding:16px 0;}
@media(max-width:960px){.sidebar{display:none;}.mobile-header{display:flex;}.main{padding:0 22px 70px;}h1.page-title{font-size:2.6rem;}.two-col{grid-template-columns:1fr;}}