/* CSS Variables & Reset */

[hidden] {
    display: none !important;
}

:root {
    color-scheme: light;
    --primary: #14b98f;
    --primary-dark: #0e9b76;
    --secondary: #5a6a80;
    --danger: #dc2626;
    --success: #16a34a;
    
    --bg-main: #f4f6f9;
    --bg-card: #ffffff;
    --bg-hover: #eef1f5;
    --surface-elevated: #f0f3f7;
    --surface-muted: #eef1f5;
    --surface: #ffffff;
    --bg-secondary: #eef1f5;
    --input-bg: #ffffff;

    --link-color: #0f9b75;
    --accent: #14b98f;
    --accent-muted: #eaf6f1;
    
    --text-primary: #1c2430;
    --text-secondary: #5a6a80;
    --text-muted: #8893a3;
    --control-disabled-fg: #64748b;
    --text-on-primary: #f8fafc;
    --text-on-danger: #f8fafc;
    
    --border-color: #e3e8ef;
    --border-radius: 8px;

    /* Layout tokens (Simple Design System + 8px grid) */
    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 24px;
    --space-6: 32px;
    --space-7: 48px;

    /* Semantic padding aliases (8px grid) */
    --pad-control-y: var(--space-2);
    --pad-control-x: var(--space-3);
    --pad-control-y-lg: var(--space-3);
    --pad-control-x-lg: var(--space-4);
    --pad-surface: var(--space-4);
    --pad-overlay: var(--space-5);
    --pad-popover: var(--space-2);
    --pad-popover-body: var(--space-3);

    --z-base: 0;
    --z-above-base: 1;
    --z-sticky-cell: 2;
    --z-sticky-header: 3;
    --z-local-overlay: 10;
    --z-dropdown: 100;
    --z-sticky-chrome: 200;
    --z-dock: 500;
    --z-popover: 650;
    --z-banner: 800;
    --z-modal: 1100;
    --z-modal-popover: 1200;
    --z-toast: 1300;
    --z-view-as: 1400;
    --z-critical: 1500;
    /* Legacy aliases */
    --z-context-menu: var(--z-dock);
    --z-tab-warnings: var(--z-banner);
    --z-header-popover: var(--z-modal-popover);

    --text-h1: 3rem;
    --text-h2: 2.5rem;
    --text-h3: 2rem;
    --text-h4: 1.5rem;
    --text-h5: 1.25rem;
    --text-h6: 1.125rem;
    --text-body-xl: 1.125rem;
    --text-body-lg: 1rem;
    --text-body-md: 0.875rem;
    --text-body-sm: 0.75rem;
    --text-body-xs: 0.625rem;

    --leading-heading-tight: 1.1;
    --leading-heading: 1.2;
    --leading-body: 1.4;

    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;
    --radius-card: 10px;
    --radius-full: 9999px;

    --touch-min: 44px;

    --safe-top: env(safe-area-inset-top, 0px);
    --safe-right: env(safe-area-inset-right, 0px);
    --safe-bottom: env(safe-area-inset-bottom, 0px);
    --safe-left: env(safe-area-inset-left, 0px);

    --chip-bg: #e2e8f0;
    --chip-color: #1e293b;

    --bp-sm: 640px;
    --bp-md: 768px;
    --bp-lg: 900px;
    --bp-xl: 1100px;
    --bp-tablet: 1024px;

    --split-sidebar-min: 220px;
    --split-sidebar-max: 300px;
    --class-notes-sidebar-min: 280px;
    --class-notes-sidebar-max: 380px;
    --editor-prose-max: 48rem;

    --shadow-sm: 0 1px 4px rgba(12, 12, 13, 0.1), 0 1px 4px rgba(12, 12, 13, 0.05);
    --shadow-md: 0 4px 4px -1px rgba(12, 12, 13, 0.1), 0 4px 4px -1px rgba(12, 12, 13, 0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-dialog: 0 16px 32px -4px rgba(12, 12, 13, 0.1), 0 4px 4px -4px rgba(12, 12, 13, 0.05);
    
    --holiday-bg: #fef3c7;
    --holiday-border: #f59e0b;

    --top-bar-bg: rgba(255, 255, 255, 0.94);
    --top-bar-shadow: 0 4px 16px rgba(20, 30, 50, 0.08);
    --toolbar-section-border: #d4dbe4;
    --toolbar-field-bg: #ffffff;
    --toolbar-field-border: #d4dbe4;

    /* ClassManager redesign — skeuo chrome + calm chips */
    --brand-accent: #14b98f;
    --brand-accent-dark: #06241c;
    --shell-zone-track-bg: #eef1f5;
    --shell-zone-active-top: #14b98f;
    --shell-segment-active-bg: linear-gradient(180deg, #22d6a8, #12a37f);
    --shell-segment-inactive-bg: linear-gradient(180deg, #ffffff, #eef2f6);
    --lock-badge-bg: linear-gradient(180deg, #1ed3a4, #0e9b76);
    --lock-badge-text: #128a68;
    --chip-calm-fill-alpha: 0.14;
    --chip-calm-text: #243244;
    --chip-calm-subtext: #6b7689;
    --calendar-card-border: #e3e8ef;
    --calendar-grid-line: #eef1f5;

    --notify-duration-in: 0.42s;
    --notify-duration-out: 0.32s;
    --notify-ease-in: cubic-bezier(0.16, 1, 0.3, 1);
    --notify-ease-out: cubic-bezier(0.4, 0, 1, 1);

    --btn-print-bg: #eff6ff;
    --btn-print-border: #93c5fd;
    --btn-print-color: #1d4ed8;
    --btn-print-hover-bg: #dbeafe;
    --btn-lang-bg: #f5f3ff;
    --btn-lang-border: #c4b5fd;
    --btn-lang-color: #5b21b6;
    --btn-lang-hover-bg: #ede9fe;
    --btn-theme-bg: #f1f5f9;
    --btn-theme-border: #cbd5e1;
    --btn-theme-color: #334155;
    --btn-theme-hover-bg: #e2e8f0;

    --print-section-options-accent: #2563eb;
    --print-section-options-tint: #eff6ff;
    --print-section-books-accent: #16a34a;
    --print-section-books-tint: #f0fdf4;
    --print-section-lessons-accent: #7c3aed;
    --print-section-lessons-tint: #f5f3ff;
    --print-section-data-accent: #dc2626;
    --print-section-data-tint: #fef2f2;

    --tab-print-inactive-bg: #f0fdfa;
    --tab-print-inactive-color: #0f766e;
    --tab-print-inactive-border: #99f6e4;
    --tab-print-hover-bg: #ccfbf1;
    --tab-print-active-bg: #0f766e;

    --status-success-bg: #ecfdf5;
    --status-success-color: #065f46;
    --status-success-border: #a7f3d0;
    --status-error-bg: #fef2f2;
    --status-error-color: #991b1b;
    --status-error-border: #fecaca;

    --badge-warn-bg: #fef3c7;
    --badge-warn-color: #b45309;

    --lock-btn-bg: #ffffff;
    --lock-btn-border: #cbd5e1;
    --lock-btn-hover-bg: #f1f5f9;
    --lock-status-free-bg: #f8fafc;
    --lock-status-free-border: #e2e8f0;
    --lock-status-held-bg: #ecfdf5;
    --lock-status-held-border: #a7f3d0;
    --lock-status-blocked-bg: #fef2f2;
    --lock-status-blocked-border: #fecaca;
    --lock-status-pending-bg: #fffbeb;
    --lock-status-pending-border: #fcd34d;
    --lock-status-waiting-bg: #eff6ff;
    --lock-status-waiting-border: #93c5fd;
    --banner-warn-bg: #fef3c7;
    --banner-warn-border: #f59e0b;
    --banner-warn-color: #78350f;
    --warn-badge-bg: #d97706;
    --warn-badge-fg: var(--text-on-primary);
    --banner-error-bg: #fee2e2;
    --banner-error-border: #f87171;
    --banner-error-color: #7f1d1d;
    --banner-info-bg: #eff6ff;
    --banner-info-border: #93c5fd;
    --banner-info-color: #1e40af;

    --banner-view-as-bg: #b45309;
    --banner-view-as-fg: #fffbeb;
    --banner-view-as-border: #92400e;
    --banner-view-as-exit-bg: #fffbeb;
    --banner-view-as-exit-fg: #92400e;
    --banner-view-as-exit-border: #fde68a;
    --banner-view-as-exit-hover-bg: #fef3c7;

    --font-main: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: ui-monospace, 'Cascadia Code', 'Segoe UI Mono', monospace;

    /* Sticky offsets: set from JS to match #appTopBar height */
    --app-chrome-sticky-top: 72px;
    /* Cohorts setup board: palette sticky top + viewport lock (set from JS) */
    --cohorts-palette-sticky-top: calc(var(--app-chrome-sticky-top) + 4.5rem);
    --cohorts-board-chrome-height: 12rem;
    /* Calendar month headers: app bar + floating visibility dock (set from JS) */
    --calendar-month-sticky-top: var(--app-chrome-sticky-top);
    /* One month ≈ one viewport below sticky chrome on the calendar tab */
    --calendar-month-gap: 20px;
    --calendar-month-view-height: calc(100dvh - var(--calendar-month-sticky-top) - var(--calendar-month-gap));

}

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

html {
    scrollbar-gutter: stable;
}

body {
    font-family: var(--font-main), 'Malgun Gothic', 'Apple SD Gothic Neo', 'Noto Sans KR', sans-serif;
    font-size: var(--text-body-lg);
    background: var(--bg-main);
    color: var(--text-primary);
    line-height: var(--leading-body);
    min-height: 100vh;
    overscroll-behavior: none;
}

.scroll-region {
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: contain;
}