@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300;400;500;700&family=Space+Grotesk:wght@400;500;700&display=swap');

:root {
  --momiji: #e8453c;
  --momiji-dark: #c0312a;
  --momiji-soft: rgba(232,69,60,0.1);
  --momiji-glow: rgba(232,69,60,0.25);
  --bg: #0d0d0f;
  --surface: #17171b;
  --surface2: #1f1f25;
  --surface3: #26262e;
  --border: rgba(255,255,255,0.07);
  --text: #f0f0f0;
  --text-muted: #888;
  --text-dim: #555;
  --radius: 16px;
  --radius-sm: 10px;
}

[data-theme="light"] {
  --bg: #f5f5f7;
  --surface: #ffffff;
  --surface2: #f0f0f2;
  --surface3: #e5e5ea;
  --border: rgba(0,0,0,0.08);
  --text: #1a1a1a;
  --text-muted: #555;
  --text-dim: #999;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Noto Sans JP', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 20px;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: radial-gradient(ellipse 50% 60% at 50% 40%, rgba(232,69,60,0.07) 0%, transparent 60%);
  pointer-events: none;
}

.container { width: 100%; max-width: 400px; position: relative; z-index: 1; }

.nav-header { margin-bottom: 24px; }
.back-link { color: var(--text-dim); text-decoration: none; font-size: 13px; font-weight: 500; transition: color 0.2s; }
.back-link:hover { color: var(--momiji); }

/* AUTH CARD */
.auth-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 32px 28px;
  text-align: center;
}

.auth-icon { font-size: 36px; margin-bottom: 8px; }

h1 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 24px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 24px;
}

/* TABS */
.auth-tabs {
  display: flex;
  background: var(--surface2);
  border-radius: var(--radius-sm);
  padding: 4px;
  margin-bottom: 24px;
  gap: 4px;
}

.tab-btn {
  flex: 1;
  background: none;
  border: none;
  padding: 10px;
  font-family: 'Noto Sans JP', sans-serif;
  font-weight: 700;
  font-size: 14px;
  color: var(--text-dim);
  cursor: pointer;
  border-radius: 8px;
  transition: all 0.2s;
}

.tab-btn.active {
  background: var(--surface3);
  color: var(--momiji);
}

/* FORM */
.form-group { margin-bottom: 12px; text-align: left; }

input {
  width: 100%;
  padding: 12px 16px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: 'Noto Sans JP', sans-serif;
  font-size: 14px;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

input:focus {
  border-color: var(--momiji);
  box-shadow: 0 0 0 3px var(--momiji-soft);
}

input::placeholder { color: var(--text-dim); }

#submit-btn {
  width: 100%;
  padding: 13px;
  background: var(--momiji);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-family: 'Noto Sans JP', sans-serif;
  font-weight: 700;
  font-size: 15px;
  cursor: pointer;
  margin-top: 8px;
  transition: all 0.2s;
  box-shadow: 0 4px 14px var(--momiji-glow);
}

#submit-btn:hover {
  background: var(--momiji-dark);
  transform: translateY(-1px);
  box-shadow: 0 6px 18px var(--momiji-glow);
}

#submit-btn:active { transform: translateY(0); }

.error-text {
  color: var(--momiji);
  font-size: 13px;
  margin-top: 14px;
  min-height: 18px;
  font-weight: 700;
}

/* NAV */
.menu-icon {
  position: fixed; top: 20px; left: 20px;
  width: 42px; height: 42px;
  display: flex; align-items: center; justify-content: center;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 50%; font-size: 18px; cursor: pointer; z-index: 1000;
  color: var(--text-muted); transition: all 0.2s;
}
.menu-icon:hover { border-color: var(--momiji); color: var(--text); }

.nav-menu {
  position: fixed; top: 0; left: -270px; width: 260px; height: 100%;
  background: var(--surface); border-right: 1px solid var(--border);
  padding-top: 80px; transition: left 0.3s cubic-bezier(.4,0,.2,1); z-index: 999;
}
.nav-menu.active { left: 0; }
.nav-menu a {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 24px; text-decoration: none;
  color: var(--text-muted); font-weight: 500; font-size: 14px;
  border-left: 3px solid transparent; transition: all 0.2s;
}
.nav-menu a:hover { background: var(--surface2); color: var(--text); border-left-color: var(--momiji); }
.nav-account {
  display: flex; align-items: center; gap: 10px;
  padding: 14px 24px 14px 21px; color: var(--text);
  font-weight: 700; font-size: 14px;
  border-left: 3px solid var(--momiji); background: var(--surface2);
}
.nav-avatar {
  width: 26px; height: 26px; min-width: 26px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 12px; font-weight: 700; color: white;
}
.nav-settings-link {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 24px; text-decoration: none;
  color: var(--text-muted); font-weight: 500; font-size: 14px;
  border-left: 3px solid transparent; transition: all 0.2s;
}
.nav-settings-link:hover { background: var(--surface2); color: var(--text); border-left-color: var(--momiji); }