/* StudyFlow – Smart Study Partner : Frontend Styles
   Premium white theme, blue accent, rounded cards, soft shadows, glass header. */

.sf-app {
	--sf-blue: #2F6BFF;
	--sf-blue-dark: #1E4FD6;
	--sf-blue-light: #EAF0FF;
	--sf-green: #21C08A;
	--sf-amber: #F5A524;
	--sf-red: #F5484E;
	--sf-bg: #F6F8FC;
	--sf-card: #FFFFFF;
	--sf-text: #1B2437;
	--sf-muted: #6B7590;
	--sf-border: #E7EBF3;
	--sf-radius: 16px;
	--sf-shadow: 0 8px 30px rgba(24, 39, 75, 0.08);

	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
	color: var(--sf-text);
	background: var(--sf-bg);
	border-radius: var(--sf-radius);
	padding: 20px;
	box-sizing: border-box;
}

.sf-app[data-theme="dark"] {
	--sf-bg: #10141F;
	--sf-card: #171C29;
	--sf-text: #F1F4FA;
	--sf-muted: #96A0B8;
	--sf-border: #262D3D;
	--sf-blue-light: #1B2540;
}

.sf-app *, .sf-app *::before, .sf-app *::after { box-sizing: border-box; }

.sf-app-inner { max-width: 1080px; margin: 0 auto; }

/* -------------------- Glass Top Bar -------------------- */
.sf-topbar {
	display: flex;
	justify-content: space-between;
	align-items: center;
	background: rgba(255, 255, 255, 0.65);
	backdrop-filter: blur(10px);
	-webkit-backdrop-filter: blur(10px);
	border: 1px solid var(--sf-border);
	border-radius: var(--sf-radius);
	padding: 14px 20px;
	margin-bottom: 16px;
	box-shadow: var(--sf-shadow);
	flex-wrap: wrap;
	gap: 10px;
}
.sf-topbar-left { display: flex; align-items: center; gap: 12px; }
.sf-logo-small { font-weight: 800; font-size: 17px; color: var(--sf-blue-dark); }
.sf-student-name { color: var(--sf-muted); font-size: 14px; }
.sf-topbar-right { display: flex; align-items: center; gap: 10px; }
.sf-streak-badge {
	background: linear-gradient(135deg, #FFF4E5, #FFE7C2);
	color: #B45B00;
	font-weight: 700;
	padding: 6px 12px;
	border-radius: 999px;
	font-size: 13px;
}
.sf-lang-switch {
	border: 1px solid var(--sf-border);
	border-radius: 10px;
	padding: 6px 10px;
	background: #fff;
	font-size: 13px;
	color: var(--sf-text);
}
.sf-icon-btn {
	background: #fff;
	border: 1px solid var(--sf-border);
	border-radius: 10px;
	width: 36px;
	height: 36px;
	cursor: pointer;
	font-size: 16px;
	transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.sf-icon-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(24,39,75,0.12); }

.sf-quote-strip {
	background: var(--sf-blue-light);
	color: var(--sf-blue-dark);
	border-radius: 12px;
	padding: 10px 16px;
	font-size: 13.5px;
	margin-bottom: 20px;
	font-style: italic;
}

/* -------------------- Cards -------------------- */
.sf-card {
	background: var(--sf-card);
	border: 1px solid var(--sf-border);
	border-radius: var(--sf-radius);
	padding: 20px;
	box-shadow: var(--sf-shadow);
	margin-bottom: 18px;
	animation: sfFadeIn 0.35s ease both;
}
.sf-card--center { text-align: center; }
.sf-card-header {
	display: flex;
	justify-content: space-between;
	align-items: center;
	flex-wrap: wrap;
	gap: 10px;
	margin-bottom: 14px;
}
.sf-card-header h3 { margin: 0; font-size: 16px; }
.sf-muted { color: var(--sf-muted); font-size: 13.5px; }

@keyframes sfFadeIn {
	from { opacity: 0; transform: translateY(6px); }
	to { opacity: 1; transform: translateY(0); }
}

/* -------------------- Buttons -------------------- */
.sf-btn {
	border: none;
	border-radius: 12px;
	padding: 10px 18px;
	font-weight: 600;
	font-size: 14px;
	cursor: pointer;
	transition: transform 0.12s ease, box-shadow 0.12s ease, opacity 0.12s ease;
	display: inline-flex;
	align-items: center;
	justify-content: center;
	gap: 6px;
}
.sf-btn:active { transform: scale(0.97); }
.sf-btn--primary { background: linear-gradient(135deg, var(--sf-blue), var(--sf-blue-dark)); color: #fff; box-shadow: 0 6px 18px rgba(47,107,255,0.35); }
.sf-btn--primary:hover { opacity: 0.92; }
.sf-btn--outline { background: #fff; border: 1.5px solid var(--sf-border); color: var(--sf-text); }
.sf-btn--outline:hover { border-color: var(--sf-blue); color: var(--sf-blue); }
.sf-btn--small { padding: 7px 12px; font-size: 12.5px; border-radius: 10px; }
.sf-btn--large { padding: 13px 26px; font-size: 15px; }
.sf-btn--block { width: 100%; }
.sf-btn-row { display: flex; gap: 10px; flex-wrap: wrap; }

/* -------------------- Setup form -------------------- */
.sf-setup-card { max-width: 520px; margin: 0 auto; }
.sf-setup-header { text-align: center; margin-bottom: 10px; }
.sf-logo { font-size: 22px; font-weight: 800; color: var(--sf-blue-dark); }
.sf-tagline { color: var(--sf-muted); font-size: 13px; margin-top: 2px; }
.sf-guest-icon { font-size: 40px; margin-bottom: 10px; }

.sf-form-row { margin-bottom: 14px; display: flex; flex-direction: column; gap: 6px; }
.sf-form-row label { font-size: 13px; font-weight: 600; color: var(--sf-muted); }
.sf-form-row input[type="text"],
.sf-form-row input[type="date"],
.sf-form-row input[type="time"],
.sf-form-row input[type="number"],
.sf-form-row select {
	border: 1.5px solid var(--sf-border);
	border-radius: 10px;
	padding: 10px 12px;
	font-size: 14px;
	background: #fff;
	color: var(--sf-text);
	width: 100%;
}
.sf-form-row input:focus, .sf-form-row select:focus { outline: none; border-color: var(--sf-blue); box-shadow: 0 0 0 3px rgba(47,107,255,0.15); }
.sf-form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.sf-form-message { font-size: 13px; margin-top: 10px; min-height: 18px; }
.sf-form-message.success { color: var(--sf-green); }
.sf-form-message.error { color: var(--sf-red); }

/* -------------------- Stats grid -------------------- */
.sf-stats-grid {
	display: grid;
	grid-template-columns: repeat(4, 1fr);
	gap: 14px;
	margin-bottom: 18px;
}
.sf-stat-card {
	background: var(--sf-card);
	border: 1px solid var(--sf-border);
	border-radius: var(--sf-radius);
	padding: 16px;
	box-shadow: var(--sf-shadow);
	text-align: left;
}
.sf-stat-card--exam { background: linear-gradient(135deg, var(--sf-blue), var(--sf-blue-dark)); color: #fff; border: none; }
.sf-stat-card--exam .sf-stat-label { color: rgba(255,255,255,0.85); }
.sf-stat-label { font-size: 12.5px; color: var(--sf-muted); font-weight: 600; text-transform: uppercase; letter-spacing: 0.03em; }
.sf-stat-value { font-size: 26px; font-weight: 800; margin-top: 6px; }
.sf-stat-sub { font-size: 12px; opacity: 0.85; margin-top: 2px; }

/* -------------------- Two column layout -------------------- */
.sf-two-col { display: grid; grid-template-columns: 1.4fr 1fr; gap: 18px; align-items: start; }
.sf-stack { display: flex; flex-direction: column; }

/* -------------------- Task list -------------------- */
.sf-task-list { display: flex; flex-direction: column; gap: 10px; }
.sf-task-item {
	display: flex;
	align-items: center;
	gap: 12px;
	border: 1px solid var(--sf-border);
	border-radius: 12px;
	padding: 12px 14px;
	transition: box-shadow 0.15s ease;
}
.sf-task-item:hover { box-shadow: 0 4px 14px rgba(24,39,75,0.08); }
.sf-task-item.completed { opacity: 0.55; }
.sf-task-item.completed .sf-task-title { text-decoration: line-through; }
.sf-task-checkbox {
	width: 22px; height: 22px; border-radius: 50%;
	border: 2px solid var(--sf-border); cursor: pointer;
	flex: 0 0 auto; display: flex; align-items: center; justify-content: center;
	font-size: 13px; color: #fff; background: #fff;
}
.sf-task-checkbox.checked { background: var(--sf-green); border-color: var(--sf-green); }
.sf-task-time { font-size: 12px; color: var(--sf-muted); min-width: 92px; }
.sf-task-body { flex: 1; }
.sf-task-title { font-weight: 600; font-size: 14px; }
.sf-task-sub { font-size: 12px; color: var(--sf-muted); }
.sf-task-tag { font-size: 11px; font-weight: 700; padding: 3px 9px; border-radius: 999px; text-transform: uppercase; letter-spacing: 0.03em; }
.sf-task-tag--study { background: var(--sf-blue-light); color: var(--sf-blue-dark); }
.sf-task-tag--revision { background: #FFF0DA; color: #B45B00; }
.sf-empty-state { text-align: center; color: var(--sf-muted); padding: 30px 10px; font-size: 14px; }

/* -------------------- Quote card -------------------- */
.sf-quote-card { background: linear-gradient(135deg, #F3F7FF, #FFFFFF); }
.sf-quote-text { font-size: 14.5px; font-style: italic; color: var(--sf-text); line-height: 1.55; margin: 0; }

/* -------------------- Mini timer -------------------- */
.sf-mini-timer { text-align: center; }
.sf-timer-display { font-size: 32px; font-weight: 800; color: var(--sf-blue-dark); margin-bottom: 10px; }
.sf-timer-controls { display: flex; gap: 10px; justify-content: center; }

/* -------------------- Subject manager -------------------- */
.sf-subject-list { display: flex; flex-direction: column; gap: 14px; }
.sf-subject-item { border: 1px solid var(--sf-border); border-radius: 14px; padding: 14px; }
.sf-subject-top { display: flex; justify-content: space-between; align-items: center; gap: 10px; flex-wrap: wrap; }
.sf-subject-name { font-weight: 700; font-size: 15px; }
.sf-subject-meta { font-size: 12px; color: var(--sf-muted); margin-top: 2px; }
.sf-subject-actions { display: flex; gap: 8px; }
.sf-badge { font-size: 11px; font-weight: 700; padding: 3px 8px; border-radius: 999px; }
.sf-badge--difficulty { background: #FDE7E7; color: #C23A3A; }
.sf-badge--priority { background: #E8F7EF; color: #1C9C6B; }

.sf-progress-bar-track { background: var(--sf-border); border-radius: 999px; height: 8px; margin: 10px 0; overflow: hidden; }
.sf-progress-bar-fill { background: linear-gradient(90deg, var(--sf-blue), var(--sf-green)); height: 100%; border-radius: 999px; transition: width 0.4s ease; }

.sf-chapter-list { margin-top: 8px; display: flex; flex-direction: column; gap: 6px; }
.sf-chapter-item { display: flex; align-items: center; gap: 10px; font-size: 13.5px; padding: 6px 0; border-top: 1px dashed var(--sf-border); }
.sf-chapter-item:first-child { border-top: none; }
.sf-chapter-item.completed .sf-chapter-name { text-decoration: line-through; color: var(--sf-muted); }
.sf-chapter-name { flex: 1; }
.sf-add-chapter-link { font-size: 12.5px; color: var(--sf-blue); cursor: pointer; font-weight: 600; margin-top: 6px; display: inline-block; }
.sf-delete-link { font-size: 12px; color: var(--sf-red); cursor: pointer; }

/* -------------------- Modal -------------------- */
.sf-modal { display: none; position: fixed; inset: 0; background: rgba(15, 20, 33, 0.5); z-index: 9999; align-items: center; justify-content: center; padding: 16px; }
.sf-modal.open { display: flex; }
.sf-modal-box { background: #fff; border-radius: var(--sf-radius); padding: 24px; width: 100%; max-width: 440px; position: relative; box-shadow: 0 20px 60px rgba(0,0,0,0.25); }
.sf-modal-close { position: absolute; top: 14px; right: 16px; border: none; background: none; font-size: 22px; cursor: pointer; color: var(--sf-muted); }

/* -------------------- Focus timer -------------------- */
.sf-focus-card { text-align: center; max-width: 480px; margin: 0 auto; }
.sf-timer-modes { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; margin-bottom: 14px; }
.sf-timer-mode { border: 1.5px solid var(--sf-border); background: #fff; border-radius: 10px; padding: 8px 14px; cursor: pointer; font-weight: 600; font-size: 13px; }
.sf-timer-mode.active { background: var(--sf-blue-light); border-color: var(--sf-blue); color: var(--sf-blue-dark); }
.sf-custom-timer-inputs { display: flex; gap: 12px; justify-content: center; margin-bottom: 14px; font-size: 13px; }
.sf-custom-timer-inputs input { width: 70px; margin-left: 6px; padding: 6px; border-radius: 8px; border: 1px solid var(--sf-border); }

.sf-big-timer { margin: 20px 0; }
.sf-big-timer-ring { position: relative; width: 220px; height: 220px; margin: 0 auto; }
.sf-ring-svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.sf-ring-bg { fill: none; stroke: var(--sf-border); stroke-width: 8; }
.sf-ring-fg { fill: none; stroke: var(--sf-blue); stroke-width: 8; stroke-linecap: round; stroke-dasharray: 339.3; stroke-dashoffset: 0; transition: stroke-dashoffset 1s linear; }
.sf-big-timer-display { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center; font-size: 40px; font-weight: 800; color: var(--sf-blue-dark); }
.sf-focus-phase { margin-top: 10px; font-weight: 600; color: var(--sf-muted); }
.sf-timer-controls--big { justify-content: center; margin-top: 10px; }
.sf-focus-sessions-today { margin-top: 16px; font-size: 13.5px; color: var(--sf-muted); }

/* -------------------- Progress page -------------------- */
.sf-range-tabs { display: flex; gap: 6px; }
.sf-tab { border: 1px solid var(--sf-border); background: #fff; border-radius: 999px; padding: 6px 14px; font-size: 12.5px; font-weight: 600; cursor: pointer; }
.sf-tab.active { background: var(--sf-blue); color: #fff; border-color: var(--sf-blue); }
#sf-hours-chart { width: 100%; height: auto; }
.sf-progress-bars { display: flex; flex-direction: column; gap: 14px; }
.sf-progress-row .sf-subject-top { margin-bottom: 4px; }

/* -------------------- Date nav -------------------- */
.sf-date-nav { display: flex; align-items: center; gap: 8px; }
.sf-date-nav input[type="date"] { border: 1px solid var(--sf-border); border-radius: 8px; padding: 6px 10px; }

/* -------------------- Responsive -------------------- */
@media (max-width: 820px) {
	.sf-two-col { grid-template-columns: 1fr; }
	.sf-stats-grid { grid-template-columns: repeat(2, 1fr); }
	.sf-form-grid { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
	.sf-app { padding: 12px; }
	.sf-stats-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
	.sf-stat-value { font-size: 20px; }
	.sf-topbar { padding: 10px 14px; }
	.sf-card { padding: 16px; }
	.sf-big-timer-ring { width: 170px; height: 170px; }
	.sf-big-timer-display { font-size: 30px; }
}