:root {
  --font-body: 'DM Sans', sans-serif;
  --font-display: 'Instrument Serif', serif;
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --space-1: 0.25rem; --space-2: 0.5rem; --space-3: 0.75rem;
  --space-4: 1rem; --space-5: 1.25rem; --space-6: 1.5rem;
  --space-8: 2rem; --space-10: 2.5rem; --space-12: 3rem;
  --radius-sm: 0.375rem; --radius-md: 0.5rem;
  --radius-lg: 0.75rem; --radius-xl: 1rem; --radius-full: 9999px;
  --transition: 180ms cubic-bezier(0.16, 1, 0.3, 1);
}

:root, [data-theme="light"] {
  --color-bg: #fdf6f9;
  --color-surface: #fff0f5;
  --color-surface-2: #ffffff;
  --color-surface-offset: #fce4ec;
  --color-border: rgba(194,24,91,0.15);
  --color-divider: rgba(194,24,91,0.1);
  --color-text: #2d1a22;
  --color-text-muted: #7a5060;
  --color-text-faint: #c4a0b0;
  --color-primary: #c2185b;
  --color-primary-hover: #ad1457;
  --color-primary-active: #880e4f;
  --color-primary-highlight: #fce4ec;
  --color-period: #e91e63;
  --color-period-bg: #fce4ec;
  --color-period-text: #880e4f;
  --color-predicted: #f8bbd0;
  --color-predicted-text: #ad1457;
  --color-fertile: #e8f5e9;
  --color-fertile-text: #2e7d32;
  --color-today-ring: #c2185b;
  --color-countdown: #c2185b;
  --color-error: #b71c1c;
  --color-success: #2e7d32;
  --shadow-sm: 0 1px 3px rgba(194,24,91,0.08);
  --shadow-md: 0 4px 16px rgba(194,24,91,0.12);
  --shadow-lg: 0 12px 32px rgba(194,24,91,0.16);
}

[data-theme="dark"] {
  --color-bg: #1a0d12;
  --color-surface: #251318;
  --color-surface-2: #2e1820;
  --color-surface-offset: #3a1f28;
  --color-border: rgba(233,30,99,0.2);
  --color-divider: rgba(233,30,99,0.12);
  --color-text: #f5dce6;
  --color-text-muted: #c4899f;
  --color-text-faint: #7a4d5e;
  --color-primary: #f06292;
  --color-primary-hover: #e91e63;
  --color-primary-active: #c2185b;
  --color-primary-highlight: #3a1f28;
  --color-period: #f06292;
  --color-period-bg: #3d1a28;
  --color-period-text: #f8bbd0;
  --color-predicted: #4a2030;
  --color-predicted-text: #f48fb1;
  --color-fertile: #1b2e1c;
  --color-fertile-text: #81c784;
  --color-today-ring: #f06292;
  --color-countdown: #f06292;
  --color-error: #ef9a9a;
  --color-success: #81c784;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg: 0 12px 32px rgba(0,0,0,0.5);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #1a0d12; --color-surface: #251318; --color-surface-2: #2e1820;
    --color-surface-offset: #3a1f28; --color-border: rgba(233,30,99,0.2);
    --color-divider: rgba(233,30,99,0.12); --color-text: #f5dce6;
    --color-text-muted: #c4899f; --color-text-faint: #7a4d5e;
    --color-primary: #f06292; --color-primary-hover: #e91e63;
    --color-primary-active: #c2185b; --color-primary-highlight: #3a1f28;
    --color-period: #f06292; --color-period-bg: #3d1a28; --color-period-text: #f8bbd0;
    --color-predicted: #4a2030; --color-predicted-text: #f48fb1;
    --color-fertile: #1b2e1c; --color-fertile-text: #81c784;
    --color-today-ring: #f06292; --color-countdown: #f06292;
    --color-error: #ef9a9a; --color-success: #81c784;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.3); --shadow-md: 0 4px 16px rgba(0,0,0,0.4);
    --shadow-lg: 0 12px 32px rgba(0,0,0,0.5);
  }
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: none; text-size-adjust: none; }
body { font-family: var(--font-body); font-size: var(--text-base); color: var(--color-text); background: var(--color-bg); min-height: 100dvh; -webkit-font-smoothing: antialiased; }
img, svg { display: block; max-width: 100%; }
input, button, select { font: inherit; color: inherit; }
button { cursor: pointer; background: none; border: none; }
a, button, input { transition: color var(--transition), background var(--transition), border-color var(--transition), box-shadow var(--transition); }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; border-radius: var(--radius-sm); }

/* LOGIN */
.login-screen { min-height: 100dvh; display: flex; align-items: center; justify-content: center; background: linear-gradient(135deg, #fce4ec 0%, #fdf6f9 50%, #f8bbd0 100%); padding: var(--space-4); }
[data-theme="dark"] .login-screen { background: linear-gradient(135deg, #1a0d12 0%, #251318 50%, #2e1820 100%); }
.login-card { background: var(--color-surface-2); border-radius: var(--radius-xl); padding: var(--space-10) var(--space-8); max-width: 380px; width: 100%; box-shadow: var(--shadow-lg); border: 1px solid var(--color-border); }
.login-logo { text-align: center; margin-bottom: var(--space-8); }
.login-logo svg { margin: 0 auto var(--space-4); }
.login-logo h1 { font-family: var(--font-display); font-size: var(--text-xl); color: var(--color-primary); margin-bottom: var(--space-2); }
.login-logo p { color: var(--color-text-muted); font-size: var(--text-sm); }
.login-form { display: flex; flex-direction: column; gap: var(--space-4); }
.login-form label { font-size: var(--text-sm); font-weight: 500; color: var(--color-text-muted); }
.login-form input { width: 100%; padding: var(--space-3) var(--space-4); border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-surface); font-size: var(--text-base); letter-spacing: 0.2em; text-align: center; }
.login-form input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 3px var(--color-primary-highlight); }
.login-error { color: var(--color-error); font-size: var(--text-sm); text-align: center; padding: var(--space-2); background: rgba(183,28,28,0.08); border-radius: var(--radius-sm); }

/* BUTTONS */
.btn-primary { width: 100%; padding: var(--space-3) var(--space-6); background: var(--color-primary); color: #fff; border-radius: var(--radius-md); font-weight: 600; font-size: var(--text-sm); border: none; cursor: pointer; }
.btn-primary:hover { background: var(--color-primary-hover); }
.btn-primary:active { background: var(--color-primary-active); }
.btn-secondary { width: 100%; padding: var(--space-3) var(--space-6); background: var(--color-surface-offset); color: var(--color-primary); border-radius: var(--radius-md); font-weight: 600; font-size: var(--text-sm); border: 1px solid var(--color-border); cursor: pointer; }
.btn-secondary:hover { background: var(--color-primary-highlight); }
.icon-btn { padding: var(--space-2); border-radius: var(--radius-md); color: var(--color-text-muted); display: flex; align-items: center; justify-content: center; min-width: 44px; min-height: 44px; }
.icon-btn:hover { background: var(--color-surface-offset); color: var(--color-primary); }

/* HEADER */
.app-header { position: sticky; top: 0; z-index: 100; background: var(--color-surface-2); border-bottom: 1px solid var(--color-divider); box-shadow: var(--shadow-sm); }
.header-inner { max-width: 800px; margin: 0 auto; padding: var(--space-3) var(--space-4); display: flex; align-items: center; justify-content: space-between; }
.header-logo { display: flex; align-items: center; gap: var(--space-2); font-family: var(--font-display); font-size: var(--text-lg); color: var(--color-primary); }
.header-actions { display: flex; align-items: center; gap: var(--space-1); }

/* STATUS BANNER */
.status-banner { max-width: 800px; margin: var(--space-4) auto 0; padding: 0 var(--space-4); }

/* MAIN */
.main-content { max-width: 800px; margin: 0 auto; padding: var(--space-4); display: flex; flex-direction: column; gap: var(--space-6); }

/* COUNTDOWN */
.countdown-section { background: var(--color-surface-2); border-radius: var(--radius-xl); padding: var(--space-8) var(--space-6); text-align: center; box-shadow: var(--shadow-md); border: 1px solid var(--color-border); }
.countdown-display { display: flex; flex-direction: column; align-items: center; gap: var(--space-3); }
.countdown-label { font-size: var(--text-sm); color: var(--color-text-muted); font-weight: 500; text-transform: uppercase; letter-spacing: 0.08em; }
.countdown-number { font-size: clamp(3rem, 8vw, 5rem); font-weight: 800; color: var(--color-countdown); line-height: 1; font-variant-numeric: tabular-nums; }
.countdown-sublabel { font-size: var(--text-base); color: var(--color-text-muted); }
.countdown-on-period { font-size: var(--text-lg); font-weight: 700; color: var(--color-countdown); }
.status-chip { display: inline-flex; align-items: center; gap: var(--space-2); padding: var(--space-2) var(--space-4); border-radius: var(--radius-full); font-size: var(--text-sm); font-weight: 600; }
.status-chip.on-period { background: var(--color-period-bg); color: var(--color-period-text); }
.status-chip.not-period { background: var(--color-fertile); color: var(--color-fertile-text); }
.fertile-notice { font-size: var(--text-sm); color: var(--color-fertile-text); background: var(--color-fertile); padding: var(--space-2) var(--space-4); border-radius: var(--radius-full); font-weight: 500; }

/* CALENDAR */
.calendar-section { background: var(--color-surface-2); border-radius: var(--radius-xl); padding: var(--space-6); box-shadow: var(--shadow-md); border: 1px solid var(--color-border); }
.calendar-nav { display: flex; align-items: center; justify-content: space-between; margin-bottom: var(--space-4); }
.calendar-nav h2 { font-family: var(--font-display); font-size: var(--text-lg); color: var(--color-text); }
.nav-btn { width: 44px; height: 44px; border-radius: var(--radius-md); display: flex; align-items: center; justify-content: center; font-size: 1.5rem; color: var(--color-primary); background: var(--color-surface-offset); border: 1px solid var(--color-border); cursor: pointer; }
.nav-btn:hover { background: var(--color-primary-highlight); }
.calendar-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 3px; }
.cal-day-header { text-align: center; font-size: var(--text-xs); font-weight: 600; color: var(--color-text-muted); padding: var(--space-2) 0; text-transform: uppercase; letter-spacing: 0.05em; }
.cal-day { aspect-ratio: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; border-radius: var(--radius-md); cursor: default; position: relative; min-width: 0; }
.cal-day .day-num { font-size: var(--text-xs); font-weight: 500; line-height: 1; }
.cal-day .period-day-num { font-size: clamp(0.6rem, 1.5vw, 0.7rem); color: var(--color-period-text); font-weight: 700; margin-top: 2px; }
.cal-day.empty { background: transparent; }
.cal-day.period-day { background: var(--color-period-bg); }
.cal-day.period-day .day-num { color: var(--color-period-text); font-weight: 700; }
.cal-day.today { outline: 2px solid var(--color-today-ring); outline-offset: -2px; }
.cal-day.today .day-num { color: var(--color-primary); font-weight: 800; }
.cal-day.predicted-day { background: var(--color-predicted); }
.cal-day.predicted-day .day-num { color: var(--color-predicted-text); }
.cal-day.fertile-day { background: var(--color-fertile); }
.cal-day.fertile-day .day-num { color: var(--color-fertile-text); }
.calendar-legend { display: flex; flex-wrap: wrap; gap: var(--space-4); margin-top: var(--space-4); padding-top: var(--space-4); border-top: 1px solid var(--color-divider); }
.legend-item { display: flex; align-items: center; gap: var(--space-2); font-size: var(--text-xs); color: var(--color-text-muted); }
.legend-dot { width: 12px; height: 12px; border-radius: var(--radius-sm); flex-shrink: 0; }
.period-dot { background: var(--color-period-bg); border: 1.5px solid var(--color-period); }
.today-dot { background: transparent; border: 2px solid var(--color-today-ring); }
.predicted-dot { background: var(--color-predicted); }
.fertile-dot { background: var(--color-fertile); border: 1.5px solid var(--color-fertile-text); }

/* LOG SECTION */
.log-section h2, .history-section h2 { font-family: var(--font-display); font-size: var(--text-lg); color: var(--color-text); margin-bottom: var(--space-4); }
.log-card { background: var(--color-surface-2); border-radius: var(--radius-xl); padding: var(--space-6); box-shadow: var(--shadow-md); border: 1px solid var(--color-border); }
.log-row { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-4); margin-bottom: var(--space-4); }
@media (max-width: 480px) { .log-row { grid-template-columns: 1fr; } }
.log-field { display: flex; flex-direction: column; gap: var(--space-2); }
.log-field label { font-size: var(--text-sm); font-weight: 500; color: var(--color-text-muted); }
.log-field input { padding: var(--space-3) var(--space-4); border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-surface); font-size: var(--text-sm); color: var(--color-text); }
.log-field input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 3px var(--color-primary-highlight); }
.log-actions { display: flex; flex-direction: column; gap: var(--space-3); }
.log-message { margin-top: var(--space-3); padding: var(--space-3); border-radius: var(--radius-md); font-size: var(--text-sm); text-align: center; }
.log-message.success { background: rgba(46,125,50,0.1); color: var(--color-success); }
.log-message.error { background: rgba(183,28,28,0.1); color: var(--color-error); }

/* HISTORY */
.history-list { display: flex; flex-direction: column; gap: var(--space-3); }
.history-item { background: var(--color-surface-2); border-radius: var(--radius-lg); padding: var(--space-4) var(--space-5); display: flex; align-items: center; justify-content: space-between; border: 1px solid var(--color-border); box-shadow: var(--shadow-sm); }
.history-item-info { display: flex; flex-direction: column; gap: var(--space-1); }
.history-item-dates { font-size: var(--text-sm); font-weight: 600; color: var(--color-text); }
.history-item-meta { font-size: var(--text-xs); color: var(--color-text-muted); }
.history-item-actions { display: flex; gap: var(--space-2); }
.delete-btn { padding: var(--space-2); border-radius: var(--radius-sm); color: var(--color-text-faint); font-size: var(--text-xs); }
.delete-btn:hover { color: var(--color-error); background: rgba(183,28,28,0.08); }
.history-empty { text-align: center; padding: var(--space-8); color: var(--color-text-muted); font-size: var(--text-sm); }

/* MODAL */
.modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.5); display: flex; align-items: center; justify-content: center; z-index: 200; padding: var(--space-4); backdrop-filter: blur(4px); }
.modal-card { background: var(--color-surface-2); border-radius: var(--radius-xl); padding: var(--space-6); width: 100%; max-width: 400px; box-shadow: var(--shadow-lg); border: 1px solid var(--color-border); }
.modal-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: var(--space-6); }
.modal-header h3 { font-family: var(--font-display); font-size: var(--text-lg); color: var(--color-text); }
.modal-body { display: flex; flex-direction: column; gap: var(--space-4); }
.setting-field { display: flex; flex-direction: column; gap: var(--space-2); }
.setting-field label { font-size: var(--text-sm); font-weight: 500; color: var(--color-text-muted); }
.setting-field input { padding: var(--space-3) var(--space-4); border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-surface); font-size: var(--text-base); color: var(--color-text); }
.setting-field input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 3px var(--color-primary-highlight); }

/* TOAST */
.toast { position: fixed; bottom: var(--space-6); left: 50%; transform: translateX(-50%); background: var(--color-text); color: var(--color-bg); padding: var(--space-3) var(--space-6); border-radius: var(--radius-full); font-size: var(--text-sm); font-weight: 500; z-index: 300; box-shadow: var(--shadow-lg); white-space: nowrap; }

/* UTILITY */
.hidden { display: none !important; }