/* ═══════════════════════════════════════════
   NIHONGO STUDY GUIDE — SHARED STYLES
   ═══════════════════════════════════════════ */

/* ═══ THEME ═══ */
[data-theme="dark"]{--bg:#151218;--bg2:#1a1620;--bg3:#201c28;--surface:#1e1a26;--surface2:#252130;--border:#352f40;--text:#f0ece8;--text2:#a89e94;--text3:#6b6060;--shadow:rgba(0,0,0,.6);--input-bg:#1a1620;--overlay:rgba(0,0,0,.82);--card-hover:#252130;--auth-glass:rgba(30,22,38,0.75);--auth-glass-border:rgba(255,255,255,0.08);--auth-orb1:rgba(200,75,75,0.5);--auth-orb2:rgba(76,175,125,0.4);--auth-orb3:rgba(232,145,58,0.35);--auth-orb4:rgba(226,192,122,0.3);--auth-input:rgba(255,255,255,0.05);--auth-input-border:rgba(255,255,255,0.10);}
[data-theme="light"]{--bg:#faf8f5;--bg2:#f3efe8;--bg3:#ece6dc;--surface:#fff;--surface2:#faf7f2;--border:#e0d8cc;--text:#2c2420;--text2:#6b5e54;--text3:#9e928a;--shadow:rgba(0,0,0,.12);--input-bg:#fdfbf8;--overlay:rgba(0,0,0,.5);--card-hover:#f5f0ea;--auth-glass:rgba(255,255,255,0.60);--auth-glass-border:rgba(255,255,255,0.90);--auth-orb1:rgba(200,75,75,0.3);--auth-orb2:rgba(76,175,125,0.25);--auth-orb3:rgba(232,145,58,0.2);--auth-orb4:rgba(226,192,122,0.2);--auth-input:rgba(255,255,255,0.8);--auth-input-border:rgba(200,75,75,0.2);}
:root{--n5:#4CAF7D;--n4:#E8913A;--n3:#E05577;--n2:#4A6FA5;--n1:#8B6AAE;--accent:#C84B4B;--acc2:#d46a6a;--gold:#e2c07a;--correct:#4CAF7D;--wrong:#E05577;--radius:12px;--radius-lg:20px;}

/* ═══ RESET ═══ */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
html,body{height:100%;scroll-behavior:smooth;}
body{font-family:'Noto Sans JP',sans-serif;background:var(--bg);color:var(--text);min-height:100vh;overflow-x:hidden;}
body::before{content:'';position:fixed;inset:0;pointer-events:none;z-index:0;background:radial-gradient(ellipse 60% 40% at 15% 5%,#C84B4B0a,transparent 60%),radial-gradient(ellipse 45% 30% at 85% 85%,#E8913A07,transparent 60%);}

/* ═══ FLOATING KANJI BACKGROUND ═══ */
.kanji-bg{position:fixed;inset:0;z-index:0;overflow:hidden;pointer-events:none;}
.kanji-bg span{position:absolute;font-family:'Shippori Mincho',serif;color:#ffffff04;animation:floatK linear infinite;user-select:none;will-change:transform;}
[data-theme="light"] .kanji-bg span{color:#00000005;}
@keyframes floatK{0%{transform:translateY(110vh) rotate(0deg);opacity:0;}10%{opacity:1;}90%{opacity:1;}100%{transform:translateY(-10vh) rotate(20deg);opacity:0;}}

/* ═══ AUTH MODAL ═══ */
#authModal{display:flex;position:fixed;inset:0;z-index:950;align-items:flex-start;justify-content:center;padding:16px;padding-top:60px;background:var(--overlay);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);opacity:0;pointer-events:none;visibility:hidden;transition:opacity .25s,visibility .25s;overflow-y:auto;}
#authModal.visible{opacity:1;pointer-events:all;visibility:visible;}
.auth-modal-close{position:absolute;top:12px;right:12px;width:32px;height:32px;border-radius:50%;background:var(--surface2);border:1px solid var(--border);color:var(--text2);font-size:16px;cursor:pointer;display:flex;align-items:center;justify-content:center;transition:all .2s;z-index:10;}
.auth-modal-close:hover{border-color:var(--wrong);color:var(--wrong);}
.auth-box{position:relative;z-index:10;width:100%;max-width:440px;padding:40px 36px 32px;border-radius:28px;background:var(--auth-glass);border:1px solid var(--auth-glass-border);backdrop-filter:blur(40px) saturate(180%);-webkit-backdrop-filter:blur(40px) saturate(180%);box-shadow:0 32px 80px rgba(0,0,0,0.4),0 0 0 1px rgba(255,255,255,0.05) inset,0 2px 0 rgba(255,255,255,0.12) inset;animation:authCardIn .6s cubic-bezier(.22,1,.36,1);margin-bottom:40px;flex-shrink:0;}
[data-theme="light"] .auth-box{box-shadow:0 24px 64px rgba(200,75,75,0.15),0 0 0 1px rgba(255,255,255,0.9) inset,0 2px 0 rgba(255,255,255,1) inset;}
@keyframes authCardIn{from{transform:translateY(32px) scale(0.96);opacity:0;}to{transform:none;opacity:1;}}
.auth-box::before{content:'';position:absolute;top:0;left:16px;right:16px;height:1px;border-radius:50%;background:linear-gradient(90deg,transparent,rgba(255,255,255,0.5),transparent);}
.auth-logo{text-align:center;margin-bottom:28px;}
.auth-logo-jp{font-family:'Noto Serif JP',serif;font-size:26px;font-weight:700;background:linear-gradient(135deg,var(--n5) 0%,var(--accent) 50%,var(--n3) 100%);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;letter-spacing:1px;}
.auth-logo-sub{font-family:'Space Mono',monospace;font-size:9px;color:var(--text3);letter-spacing:4px;text-transform:uppercase;margin-top:5px;}
.auth-tabs{display:flex;background:rgba(0,0,0,0.15);border-radius:50px;padding:4px;margin-bottom:24px;}
[data-theme="light"] .auth-tabs{background:rgba(0,0,0,0.06);}
.auth-tab{flex:1;padding:9px;background:none;border:none;color:var(--text3);font-family:'Space Mono',monospace;font-size:11px;letter-spacing:1px;text-transform:uppercase;cursor:pointer;border-radius:50px;transition:all .25s;}
.auth-tab.active{color:#fff;background:linear-gradient(135deg,var(--accent),var(--acc2));box-shadow:0 4px 16px rgba(200,75,75,0.45);}
.auth-field{margin-bottom:14px;position:relative;}
.auth-label{display:flex;align-items:center;gap:6px;font-size:10px;letter-spacing:1.5px;text-transform:uppercase;color:var(--text3);font-family:'Space Mono',monospace;margin-bottom:6px;}
.auth-input{width:100%;background:var(--auth-input);border:1px solid var(--auth-input-border);border-radius:14px;padding:13px 16px;color:var(--text);font-family:'Noto Sans JP',sans-serif;font-size:14px;outline:none;transition:all .25s;backdrop-filter:blur(10px);}
[data-theme="light"] .auth-input{background:rgba(255,255,255,0.85);border-color:rgba(200,75,75,0.15);color:#2c2420;}
.auth-input:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(200,75,75,0.2);}
.auth-input::placeholder{color:var(--text3);opacity:0.6;}
.auth-btn{width:100%;padding:14px;border:none;border-radius:14px;background:linear-gradient(135deg,var(--accent),var(--acc2));color:#fff;font-family:'Space Mono',monospace;font-size:13px;cursor:pointer;transition:all .3s;margin-top:6px;font-weight:700;letter-spacing:1px;box-shadow:0 8px 32px rgba(200,75,75,0.4);}
.auth-btn:hover{transform:translateY(-2px);box-shadow:0 12px 40px rgba(200,75,75,0.55);}
.auth-error{border-radius:12px;padding:12px 16px;font-size:13px;font-weight:600;line-height:1.6;margin-bottom:14px;display:none;text-align:center;backdrop-filter:none;-webkit-backdrop-filter:none;}
.auth-error.show{display:block;}
[data-theme="dark"] .auth-error.error{background:rgba(255,71,87,0.2);border:1px solid rgba(255,71,87,0.5);color:#ff6b7a;}
[data-theme="light"] .auth-error.error{background:#fde8ea;border:1px solid #f5a3aa;color:#b52533;}
[data-theme="dark"] .auth-error.success{background:rgba(0,196,154,0.2);border:1px solid rgba(0,196,154,0.5);color:#2ee6b6;}
[data-theme="light"] .auth-error.success{background:#e2f8f1;border:1px solid #82d9b8;color:#0a7a5c;}
.auth-divider{display:flex;align-items:center;gap:12px;margin:16px 0;}
.auth-divider-line{flex:1;height:1px;background:var(--auth-input-border);}
.auth-divider-text{font-size:10px;color:var(--text3);font-family:'Space Mono',monospace;letter-spacing:1px;}
.auth-guest-btn{width:100%;padding:12px;border:1px solid var(--auth-input-border);border-radius:14px;background:var(--auth-input);color:var(--text2);font-family:'Space Mono',monospace;font-size:11px;letter-spacing:1px;cursor:pointer;transition:all .25s;display:flex;align-items:center;justify-content:center;gap:8px;}
.auth-google-btn{width:100%;padding:12px;border:1px solid var(--auth-input-border);border-radius:14px;background:var(--auth-input);color:var(--text2);font-family:'Space Mono',monospace;font-size:11px;letter-spacing:1px;cursor:pointer;transition:all .25s;display:flex;align-items:center;justify-content:center;gap:8px;margin-bottom:8px;}
.auth-google-btn:hover{border-color:var(--accent);color:var(--text);}
.auth-google-btn svg{flex-shrink:0;}
.auth-guest-btn:hover{border-color:var(--accent);color:var(--text);}
.auth-btn:disabled,.auth-guest-btn:disabled,.auth-google-btn:disabled{opacity:0.7;cursor:not-allowed;transform:none !important;}

/* Password visibility toggle */
.auth-input-wrap{position:relative;}
.auth-input-wrap .auth-input{padding-right:44px;}
.auth-pass-toggle{position:absolute;right:10px;top:50%;transform:translateY(-50%);background:none;border:none;font-size:16px;cursor:pointer;padding:4px;color:var(--text3);transition:color .2s;line-height:1;}
.auth-pass-toggle:hover{color:var(--text);}

/* Password strength meter */
.pw-strength{margin-top:6px;margin-bottom:2px;}
.pw-strength-bar{height:4px;border-radius:4px;background:var(--auth-input-border);overflow:hidden;margin-bottom:4px;}
.pw-strength-fill{height:100%;border-radius:4px;transition:width .3s,background .3s;width:0%;}
.pw-strength-fill.weak{width:25%;background:#E05577;}
.pw-strength-fill.fair{width:50%;background:#E8913A;}
.pw-strength-fill.good{width:75%;background:#4CAF7D;}
.pw-strength-fill.strong{width:100%;background:#C84B4B;}
.pw-strength-text{font-family:'Space Mono',monospace;font-size:10px;letter-spacing:.5px;}
.pw-strength-text.weak{color:#E05577;}
.pw-strength-text.fair{color:#E8913A;}
.pw-strength-text.good{color:#4CAF7D;}
.pw-strength-text.strong{color:#C84B4B;}

/* Auth warning alert */
[data-theme="dark"] .auth-error.warn{background:rgba(255,159,67,0.2);border:1px solid rgba(255,159,67,0.5);color:#ffb563;}
[data-theme="light"] .auth-error.warn{background:#fff3e0;border:1px solid #f5c27a;color:#a86200;}
.auth-alert-btn{display:inline-block;margin-top:6px;padding:4px 12px;border-radius:50px;border:1px solid currentColor;background:none;color:inherit;font-family:'Space Mono',monospace;font-size:10px;cursor:pointer;letter-spacing:.5px;transition:all .2s;}
.auth-alert-btn:hover{background:rgba(255,255,255,0.1);}

/* Rate limit warning */
.auth-rate-limit{display:none;font-family:'Space Mono',monospace;font-size:11px;color:var(--n4);text-align:center;padding:8px;margin-bottom:8px;background:rgba(255,159,67,0.08);border-radius:10px;}

/* Loading spinner */
.spinner{display:inline-block;width:14px;height:14px;border:2px solid rgba(255,255,255,0.3);border-top-color:#fff;border-radius:50%;animation:spin .6s linear infinite;vertical-align:middle;margin-right:4px;}
@keyframes spin{to{transform:rotate(360deg);};}

/* Forgot password */
.auth-back-btn{background:none;border:none;color:var(--text2);font-family:'Space Mono',monospace;font-size:11px;cursor:pointer;letter-spacing:.5px;display:flex;align-items:center;gap:4px;margin-bottom:16px;transition:color .2s;}
.auth-back-btn:hover{color:var(--accent);}
.forgot-msg{display:none;font-size:12px;line-height:1.6;padding:10px 14px;border-radius:10px;text-align:center;margin-bottom:12px;}
.auth-forgot-link{background:none;border:none;color:var(--accent);font-family:'Space Mono',monospace;font-size:11px;cursor:pointer;letter-spacing:.5px;opacity:.8;transition:opacity .2s;margin-top:4px;}
.auth-forgot-link:hover{opacity:1;}

/* ═══ SHARED: APP HEADER ═══ */
header{padding:13px 18px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--border);background:var(--bg);backdrop-filter:blur(20px);position:sticky;top:0;z-index:100;gap:10px;}
.logo{display:flex;align-items:center;gap:8px;cursor:pointer;text-decoration:none;}
.logo-jp{font-family:'Noto Serif JP',serif;font-size:22px;font-weight:700;background:linear-gradient(135deg,var(--n5),var(--accent),var(--n3));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;}
.logo-en{font-family:'Space Mono',monospace;font-size:8px;color:var(--text3);letter-spacing:3px;text-transform:uppercase;margin-top:2px;}
.header-right{display:flex;align-items:center;gap:8px;}
.user-badge{display:flex;align-items:center;gap:7px;background:var(--surface);border:1px solid var(--border);border-radius:50px;padding:4px 12px 4px 5px;cursor:pointer;transition:all .2s;}
.user-badge:hover{border-color:var(--accent);}
.user-avatar{width:24px;height:24px;border-radius:50%;background:linear-gradient(135deg,var(--accent),var(--n3));display:flex;align-items:center;justify-content:center;font-size:10px;font-weight:700;color:#fff;font-family:'Space Mono',monospace;}
.user-name{font-size:11px;font-family:'Space Mono',monospace;color:var(--text);}
.icon-btn{width:34px;height:34px;border-radius:50%;border:1px solid var(--border);background:var(--surface);color:var(--text2);cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:15px;transition:all .2s;flex-shrink:0;}
.icon-btn:hover{border-color:var(--accent);color:var(--text);}
.stat-pill{display:flex;align-items:center;gap:5px;background:var(--surface);border:1px solid var(--border);border-radius:50px;padding:5px 11px;font-size:11px;font-family:'Space Mono',monospace;color:var(--text2);}
.stat-dot{width:6px;height:6px;border-radius:50%;}
.dropdown{position:relative;}
.dropdown-menu{position:absolute;top:calc(100% + 6px);right:0;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);min-width:200px;box-shadow:0 12px 40px var(--shadow);z-index:200;overflow:hidden;}
.dropdown-menu.hidden{display:none;}
.dd-item{display:flex;align-items:center;gap:8px;width:100%;padding:11px 14px;background:none;border:none;color:var(--text);font-size:13px;cursor:pointer;transition:background .15s;text-align:left;}
.dd-item:hover{background:var(--card-hover);}
.dd-sep{height:1px;background:var(--border);margin:4px 0;}

/* ═══ SECTION NAV BAR ═══ */
.section-nav{display:flex;align-items:center;gap:0;background:var(--surface);border-bottom:2px solid var(--border);padding:0 18px;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:none;}
.section-nav::-webkit-scrollbar{display:none;}
.section-nav a{display:flex;align-items:center;gap:6px;padding:12px 16px;font-family:'Space Mono',monospace;font-size:12px;font-weight:500;letter-spacing:.3px;color:var(--text3);text-decoration:none;white-space:nowrap;border-bottom:2px solid transparent;margin-bottom:-2px;transition:all .2s;}
.section-nav a:hover{color:var(--text);background:var(--card-hover);}
.section-nav a.active{color:var(--accent);border-bottom-color:var(--accent);font-weight:700;}
.section-nav .snav-icon{font-size:14px;line-height:1;}
@media(max-width:768px){
  .section-nav{display:none;}
}

main{flex:1;padding:18px;max-width:1100px;margin:0 auto;width:100%;}

/* ═══ SHARED: UTILITY ═══ */
.section-title{font-family:'Noto Serif JP',serif;font-size:24px;margin-bottom:5px;}
.section-sub{color:var(--text2);font-size:13px;margin-bottom:16px;}
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:20px;}
#toast{position:fixed;bottom:30px;left:50%;transform:translateX(-50%) translateY(20px);background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:12px 24px;font-size:13px;box-shadow:0 8px 30px var(--shadow);z-index:9999;opacity:0;pointer-events:none;transition:opacity .25s,transform .25s;}
#toast.show{opacity:1;transform:translateX(-50%) translateY(0);}

@media(max-width:600px){
  header{padding:10px 13px;}
  .logo-jp,.logo-en{display:none;}
  .header-right .stat-pill{display:none;}
  .user-name{display:none;}
}